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Tutorial (pdf version) - Natural Resource Ecology Laboratory

1. 56 January 2001 CENTURY Tutorial Wos ATIS Wos D IN 92 S d NE LBEOOOQAA 51009 3sSdwvoowvad 5 NE BOCOM 9 9999 S d NE LIBIOOOAA 2L OOOAA SSHONTHE dyad 9301915394 1008 9791534 3ovJdadns lapauugns aug 140 amp L anfi S do NEEL BLOONS nae aoe 2100842 aal 51008 454902 202924 951207 S d NE LISOONN TH jenuus AGOTA uaganpa4g uaugJg gurjjenuuy CX eB 000M 3o8v1 uaganpalg 10034 aui 25 OO Eg NIC LIBHOEH e PE SSeS SEE S3HONVHE am eadusa WAL unmgeidimalg AWON uiufirq ua TN 4 51009 S d NE LSANITTH 5997 57 CENTURY Tutorial PRECIPITATIOH HTERCEPTIOH EVAP SOIL WATER 0 15 cm ASMOS a SOIL WATER 15 30 ASMOS ur 2 pact 30 45 ASMOS 13 45 60 ASMOS 4 SOIL WATER 50 90 ASMOS 5 STREAM FLOW STRE AM 1 DEEP SOIL STOR AGE AS
2. 10101 2 31405 03805 1105 230 2 THNIIN L 15 UI enuuy ZNN LINL unnenarnma a msi Jo 10 c HALOS d JINY DHO d 430 Janis iz TIOS z gv d 211091134 6 d 2110911314 2 15 M0138 INS qa dans urit d 3 N oumb 26 gt 9 IE 3 ielgAnTOG 2 0909025 d n d qvad GNI OI c SANUS d YAONJA 153AuHVH N 18 61 January 2001 CENTURY Tutorial 10 4402 yaya 5401964 10 aug sous N32 ur nudis 10 se 144 5 T743 HIH 2 Wy 15 5 3H2v 11 E H3A x1 TH3 S 8 E 9 235 T 5 i AU 0 235 Ve bursa LFTHSNIIN 5 qar tf IN EJIE NOS JAIS SV d 5132 Was MOTS E zi3tWos 31H 20 Ns EJ d LH add UIE 2921415 5 5 nouo Avo138 fe 2 dev L3 Ao1318 E LOL334 nne or WUE akel
3. 20 Moy L 4 THYNLINYLS 0009 0001 JAIS SV d S d N 05 01 SLNSIMINN MOTS AYTAY A 036 JINVYOHO Tos TWILNA LOd OH 108 09 TAGOW CENTURY Tutorial January 2001 1 3 Soil Organic Matter Model The soil organic matter model simulates SOM dynamics for soil active slow and passive pools while dead litter material 15 represented using aboveground and belowground structural and metabolic pools Figure 1 2 The active pool approximately 296 of the total SOM pool includes soil microbes and microbial products with short turnover times 1 3 months The slow SOM pool 45 to 60 of total soil SOM includes resistant plant material derived from structural plant material and stabilized soil microbial products that have turnover times ranging from 10 to 50 years depending on the climate The passive pool 45 to 50 of total SOM includes physically and chemically stabilized SOM that is very resistant to decomposition turnover times from 400 to 4000 years The structural material includes cellulose hemi cellulose and lignin fraction of plant material resistant to decomposition while the metabolic material is readily decomposable Plant litter material 1s split into structural and metabolic material as a function of the lignin to nitrog
4. view a lis CENTURY output file open the application in which you wish to view the file and select the File Open option from the main menu Use the drop down arrow to the right of the Look in text box to locate the directory where your CENTURY output is located If you do not see any files with a lis extension listed you will need to change the file type for the listing being displayed To do this select the drop down arrow to the right of the Files of Type text box and click on the Files option in the drop down list Once you have located your output file click on it to highlight the filename and then select the Open button to open the selected file 6 2 Using Microsoft Excel Using a spreadsheet application such as Microsoft Excel gives you the added capability of creating graphs of the CENTURY output variable values so that you can easily view the trends that occur over the length of the simulation To open a lis CENTURY output file in Microsoft Excel select the File Open option from the main menu Click on the down arrow to the right of the Files of Type text box and select the Files option from the drop down list Use the drop down arrow to the right of the Look in text box to locate the directory where your CENTURY output is located Locate the lis file you wish to examine click on it to highlight the filename and then select the Open button This will bring up the Text Import Wizard In Step 1 select the
5. Appendix 3 14 Appendix 3 CENTURY Parameterization Workbook 7 HARVEST SENESCENCE PARAMETERS The user controls the amount of C and nutrients allocated to grain effects of water stress on harvest and N volatilized at harvest or senescence through the following parameters See parameter definitions and Fig 3 15 the Century User s Manual Tall Winter Short Alfalfa Soy Corn 57272 B himax mem p e ppp ema ws pem e emm es ws o e os eem wes ees ess oo 8 SHOOT AND ROOT DEATH RATES AND NUTRIENT RETRANSLOCATION PARAMETERS The user controls the maximum monthly shoot death rate senescence month shoot death rate the influence of shading on death rate shoot fall rate maximum root death rate and the fraction of nutrients retranslocated from leaves at death See Fig 3 16 the Century Users s Manual arase umsat pe T NEN DET oe ie fsdeth 1 mem s feo mee es foo foo fo fo eo d fo Appendix 3 15 Appendix 3 CENTURY Parameterization Workbook 9 SYMBIOTIC BIOLOGICAL FIXATION N fixation is parameterized as snfxmx 2 maximum g N fixed per g C NPP This can be approximated as symbiotic N fixation annual NPP g C Remember to set this to the maximum value it will be reduced if nitrogen availability is high enough Enter the value used below snfxmx
6. 1 SDRMAE 1 Annual accumulator of N removed from standing dead during grazing fire for grass crop g m2 SECNDY 1 Secondary N g m2 SHRMAK 1 Annual accumulator of N removed from shoots during grazing fire for grass crop g m2 SNFXAC 1 Annual accumulator for symbiotic N fixation for grass crop system SNFXAC 2 Annual accumulator for symbiotic N fixation for forest system SOILNM 1 Annual accumulator for net mineralization of N in soil compartments soil organic matter belowground litter dead coarse roots g m2 SOM1K 1 1 N in surface microbe pool g m2 SOM1E 2 1 N in active soil organic matter g m2 Appendix 2 11 Appendix 2 CENTURY Output Variables by Category SOM2E 1 N in slow pool soil organic matter g m2 N in passive soil organic matter g m2 SOMSE 1 Sum of N in SOMIE SOM2E and g m2 SOMTE 1 Total N in soil organic matter including belowground structural metabolic STDEDE 1 N in standing dead for grass crop g m2 STREAM 2 N from mineral leaching of stream flow base flow storm flow g m2 STREAM 6 N from organic leaching of stream flow base flow storm flow g m2 STRMNR 1 1 Net mineralization for for surface structural litter STRMNR 2 1 Net mineralization for for soil structural litter STRUCE 1 1 Surface litter structural g m2 STRUCE 2 1 Soil litter structural g m2 SUM
7. 10 Appendix 2 CENTURY Output Variables by Category CENTURY Output Variables By Category CO2 Output Variables AMT1C2 Annual accumulator for surface CO2 loss due to microbial respiration during litter decomposition AMT2C2 Annual accumulator for soil CO2 loss due to microbial respiration during litter decomposition AS11C2 Annual accumulator for CO2 loss due to microbial respiration during soil organic matter decomposition of surface SOMI to SOM2 AS21C2 Annual accumulator for CO2 loss due to microbial respiration during soil organic matter decomposition of soil SOM1 to SOM2 and SOM3 AS2C2 Annual accumulator for CO2 loss due to microbial respiration during soil organic matter decomposition of SOM2 to soil SOM1 and SOMS AS3C2 Annual accumulator for CO2 loss due to microbial respiration during soil organic matter decomposition of to soil SOMI AST1C2 Annual accumulator for CO2 loss due to microbial respiration during litter decomposition of surface structural into SOM1 and SOM2 AST2C2 Annual accumulator for CO2 loss due to microbial respiration during litter decomposition of soil structural into SOM1 and SOM2 CO2CCE 1 1 1 In a grassland crop system the calculated effect on minimum C N ratios of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CCE 1 1 2 In a grassland crop system the calculated effect on minimum C P ratios of doubling the atmospheric CO2 concentration fro
8. EPRODC 2 Actual monthly P uptake for grass crop g m2 month EPRODF 2 Actual monthly P uptake forest system g m2 month ERETA 2 Annual accumulator of P returned to system during grazing fire for grass crop g m2 year ERMVST 2 Amount of P removed as straw during harvest for grass crop g m2 month ESRSNK 2 P source sink g m2 EUPACC 2 Growing season accumulator for P uptake by grass crop or tree g m2 EUPAGA 2 Aboveground growing season accumulator for P uptake by plants for grass crop g m2 EUPBGA 2 Belowground growing season accumulator for P uptake by plants for grass crop g m2 EUPPRT 1 2 Growing season accumulator for P uptake by forest leaf component g m2 EUPPRT 2 2 Growing season accumulator for P uptake by forest fine root component g m2 EUPPRT 3 2 Growing season accumulator for P uptake by forest fine branch component g m2 EUPPRT 4 2 Growing season accumulator for P uptake by forest large wood component g m2 Appendix 2 14 Appendix 2 CENTURY Output Variables by Category EUPPRT 5 2 Growing season accumulator for P uptake by forest coarse root component g m2 FBRCHE 2 P in forest system fine branch component g m2 FERTOT 2 Accumulator for P fertilizer FORSTG 2 Retranslocation P storage pool for forest FROOTE 2 P in forest system fine root component g m2 FRSTE 2 Sum of P in forest system live components RLEAVE 2 FROO
9. TENOS D M ZS Nos 035405 pos 12101 2305 d IHUN 1105 0401 2 THN unnezie jung jenuug ZNAN LINL ame SIno 10 10 qu acgvogs A 03805 ATSNOYLS E did lt m d qavi 4 a be d LN TH Vd BF hos EAMES d d 38021IN 329 NS Wier E ZILIN DIOLS z ger songs d LIN 16 d 14 d Wuniomils MO138 32V NS iOS One oj d dn ong zu Ves 3 ielgAnTOG 0909025 d m d CANTE EIS C1 SANUS d YAONJA 153AuvVH 15 CENTURY Tutorial January 2001 1 4 Soil Water and Temperature Model The CENTURY model uses a simplified water budget model to calculate monthly bare soil evaporation interception and transpiration water loss stored soil water snow water content stream flow and saturated water flow between soil layers Figure 1 6 Interception and bare soil water loss are calculated as fractions of the monthly precipitation and are subtracted from monthly precipitation before the water 15 added to the soil Bare soll water loss 1s a function of aboveground biomass decreasing with increasing biomass
10. Appendix 2 CENTURY Output Variables by Category DSTRUC 2 Delta 13C value for soil structural C for stable isotope labeling LHZCAC Accumulator for C inputs to 0 20 cm layer from the lower horizon pools associated with soil erosion g m2 METABC 1 Metabolic C in surface litter g m2 2 Metabolic C in soil litter g m2 METCIS 1 1 Metabolic surface litter unlabeled C g m2 METCIS 1 2 Metabolic surface litter labeled C g m2 METCIS 2 1 Metabolic soil litter unlabeled C g m2 METCIS 2 2 Metabolic soil litter labeled C g m2 SCLOSA Accumulated C lost from soil organic matter by erosion total C for entire simulation g m2 SCLOSS Total loss from soil organic matter by erosion for current month g m2 SOM1C 1 C in surface microbe pool g m2 SOM1C 2 C in active soil organic matter g m2 SOMICI 1 1 Unlabeled C in surface microbe pool g m2 SOMICI 1 2 Labeled C in surface microbe pool g m2 SOMICI 2 1 Unlabeled C in active soil organic matter g m2 SOM1CI 2 2 Labeled C in active soil organic matter g m2 SOM2C C in slow pool soil organic matter g m2 SOM2CI 1 Unlabeled C in slow pool soil organic matter g m2 SOM2CI 2 Labeled C in slow pool soil organic matter g m2 SOMSC C in passive soil organic matter g m2 Unlabeled C in passive soil organic matter g m2 SOMSCI 2 Labeled C in passive soil organic mat
11. C in forest system leaf component g m2 RLVACC Growing season accumulator for C production forest system leaf compartment RLVCIS 1 Unlabeled C in forest system leaf component g m2 RLVCIS 2 Labeled in forest system leaf component g m2 RLWACC Growing season accumulator for C production in forest system large wood component g m2 y RLWCIS 1 Unlabeled C in forest system large wood component g m2 RLWCIS 2 Labeled C in forest system large wood component g m2 RLWODC C in forest system large wood component g m2 SUMRSP Monthly maintenance respiration in the forest system g m2 TCREM Total C removed during forest removal events g m2 Appendix 2 7 Appendix 2 CENTURY Output Variables by Category WILIG Lignin content of dead fine branches fraction lignin in WOOD1 W2LIG Lignin content of dead large wood fraction lignin in WOOD2 W3LIG Lignin content of dead coarse roots fraction lignin in WOODS WDICIS 1 Unlabeled C in forest system WOOD dead fine branch material g m2 WD1CIS 2 Labeled C in forest system WOOD dead fine branch material g m2 WD2CIS 1 Unlabeled C in forest system WOOD2 dead large wood material g m2 WD2CIS 2 Labeled in forest system WOOD2 dead large wood material g m2 WDS3CIS 1 Unlabeled C in forest system WOOD3 dead coarse root material g m2 WDS3CIS 2 Labeled C in forest system WOODS dead coarse root material g m2
12. SIMNR 1 2 Net mineralization for P for surface microbes 1 1 2 SIMNR 2 2 Net mineralization for P for active pool SOM1E 2 2 S2MNR 2 Net mineralization for P for slow pool SOM2E 2 SS3MNR 2 Net mineralization for P for passive pool 2 SDRMAE 2 Annual accumulator of P removed from standing dead during grazing fire for grass crop g m2 SECNDY 2 Slowly sorbed P g m2 SHRMAE 2 Annual accumulator of P removed from shoots during grazing fire for grass crop g m2 SOILNM 2 Annual accumulator for net mineralization of P in soil compartments soil organic matter belowground litter dead coarse roots g m2 SOM1K 1 2 P in surface microbe pool g m2 SOM1E 2 2 P in active soil organic matter g m2 SOM2E 2 P in slow pool soil organic matter g m2 SOMS3E 2 P in passive soil organic matter g m2 SOMSE 2 Sum of P in SOMIE and g m2 SOMTE 2 Total P in soil organic matter including belowground structural metabolic STDEDE 2 P in standing dead for grass crop g m2 Appendix 2 16 Appendix 2 CENTURY Output Variables by Category STREAM 8 P from mineral leaching of stream flow base flow storm flow g m2 STREAM 7 P from organic leaching of stream flow base flow storm flow g m2 STRMNR 1 2 Net mineralization for P for surface structural litter STRMNR 2 2 Net mineralization for P for soil struc
13. This paper presents a description of the model the method used to test and validate the model and a summary of the application of the model for an environmental impact assessment Figure 1 1 shows that the major structural components of the CENTURY model are the plant production soil organic matter and the soil water and temperature submodels The plant production submodel calculates potential plant production and nutrient demand as a function of monthly average soil temperature and precipitation reduces plant production based on available soil nutrients and allocates new C N and P to the different live plant compartments The monthly soil water flow model calculates water balance soil water storage soil water drainage and stream flow while monthly average soil temperature is calculated as a function of aboveground plant biomass Monthly precipitation stored soil water and soil temperature control the rate of decomposition of the soil organic matter pools and the release of nutrients from the SOM pools The soil organic matter submodel simulates the dynamics of carbon and soil nutrients for the different SOM pools Decomposition of the SOM pools results in the release of soil nutrients from the SOM pools which is then available for plant uptake Dead plant material from the plant production submodel flows into the surface and belowground litter pools which are inputs to the SOM model January 2001 CENTURY Tutorial Aj
14. g m2 CGRACC Accumulator for grain and tuber production g m2 CGRAIN Economic yield of C in grain tubers g m2 CINPUT Annual C inputs CISGRA 1 Unlabeled C in grain g m2 CISGRA 2 Labeled C in grain g m2 CPRODC Total monthly C production g m2 month CRETA Annual accumulator of C returned to system during grazing fire g m2 year CRMVST Amount of C removed through straw during harvest g m2 month Appendix 2 4 Appendix 2 CENTURY Output Variables by Category CRPVAL numerical representation of the current crop used for sorting output by crop created by a system of assigning values to characters as in A 1 B 2 etc and 170 1 2 0 2 etc and adding the values together example AB2 3 2 HARMTH 0 in non harvest months 1 in a harvest month HI Harvest index CGRAIN AGLIVC at harvest PTAGC Growing season accumulator for potential aboveground C production g m2 y PTBGC Growing season accumulator for potential belowground C production g m2 y SDREMA Annual accumulator of C removed from standing dead during grazing fire g m2 SDRMAI 1 Annual accumulator of unlabeled C removed from standing dead during grazing fire g m2 SDRMAI 2 Annual accumulator of labeled C removed from standing dead during grazing fire g m2 SHREMA Annual accumulator of C removed from shoots during grazing fire g m2 SHRMAI 1 Annual accumulator of unlabeled C removed from s
15. levels on grasslands around the world Parton et al 1995 with a detailed analysis for the US Great Plains region Burke et al 1991 Schimel et al 1990 The combined effect of future environmental change and improved land use practices on soil carbon storage and plant production has been evaluated for the US Corn Belt Donigian et al 1995 while Paustian et al 1996 have used CENTURY to evaluate soil carbon storage in the US resulting from the conservation reserve program Vegetation Ecosystem Modeling and Assessment VEMAP program VEMAP 1996 has used the CENTURY model to evaluate the impact of climate change and increased levels on the natural ecosystem in the US using a 0 5 x 0 5 degree resolution and compared model results with two other biogeochemistry models The model has also been used to simulate ecosystem dynamics at the 0 5 x 0 5 degree scale for global ecosystems Schimel et al 1996 We are currently developing a daily version of the model Parton et al 1998 which simulates all of the ecosystem dynamics using more mechanistic soil water and temperature submodels and also simulates daily trace gas fluxes N20 NOx and CH3 15 CENTURY Tutorial January 2001 1 7 DAYCENT Model Description DAYCENT Parton et al 1998 DelGrosso et al 2001 Kelly et al 2000 1s the daily time step version of the CENTURY ecosystem model Simulation of trace gas fluxes through soils requires finer time scale resolution becau
16. to change to Execute GOMT number NXYR Changes to the next year If in the last year of the block changes to the first year of the block None Execute NXYR GOYR Changes to the given year in the current block A year number in the current block Execute GOYR number CPYR Copies all events in the current year to the given year year number in the current block to copy to Execute CPYR number 45 CENTURY Tutorial January 2001 NBLK Changes to the next block If this block has not yet been set up the user may set up the block by answering the set of block questions concerning the last year of simulation the number of years in the repeating sequence the data output interval value the month to start writing output the weather choice and the comment Execute NBLK GBLK Changes to the given block number if that block has already been set up If the block has not been set up the user may set up the block by answering the set of block questions concerning the last year of simulation the number of years in the repeating sequence the data output interval value the month to start writing output the weather choice and the comment The block number to change to Execute GBLK number ABLK Adds a new block by having the user answer the block questions concerning the last year of simulation the number of years in the repeating sequence the data output interval value the month
17. 0 50 Fine root dead fine Set all the corresponding cis 2 pools to 0 0 if you are not simulating isotope labeling Source for woody debris data Appendix 3 10 Appendix 3 CENTURY Parameterization Workbook 4 MINERAL INITIAL PARAMETERS minerl 1 n 1 These set the initial N g m in each soil layer If you have no data or estimates for this use 1 for the layers that include the top 20 cm of soil minerl 1 n 2 These set the initial P g m in each soil layer If you have no data or estimates for this use 1 for the layers that include the top 20 cm of soil minerl 1 n 3 These set the initial S g m in each soil layer If you have no data or estimates for this use 1 for the layers that include the top 20 cm of soil 5 WATER INITIAL PARAMETERS This is not necessary if you include an equilibrium block in your Schedule file But if you want to include precise initial conditions then enter measured or estimated values for rwcf 1l n These parameters set the initial relative water content RWC for each soil layer RWC WP FC WP where W is the measured soil water content WP is the soil water content at wilting point and FC is the soil water content at field capacity snlq is the liquid water in the snowpack cm H O snow is the snowpack water content cm H O 6 OTHER PARAMETERS Check the parameters listed below and be sure they are set to the indicated values wllig 0 0 w2lig 0 0 w3
18. 0 92 tmin 1915 13 50 8 33 8 17 0 78 1 67 7 00 9 72 8 33 5 39 0 28 6 06 8 78 tmax 1915 4 44 8 56 4 33 16 33 17 50 21 06 26 83 26 06 22 89 18 89 10 78 8 50 1916 1 57 0 31 0 37 1 68 8 07 2 90 4 27 2 84 1 06 2 64 2 06 3 06 tmin 1916 16 50 9 50 4 89 2 28 1 56 6 28 10 56 9 89 3 33 2 44 9 28 14 78 tmax 1916 0 61 8 67 14 22 14 33 20 28 25 44 32 39 27 28 24 56 14 78 8 78 1 56 To generate the weather statistical values choose 13 from the main menu weather statistics Then enter the name of the actual weather file without the wth extension Enter the name of the actual weather file 33 CENTURY Tutorial January 2001 FILE100 will generate the weather statistics and place the new monthly values for PRECIP PRCSTD PRCSKW TMN2M TMX2M into the named lt site gt 100 file Missing values in the weather file given as 99 99 are ignored when statistics are calculated FILE100 will then ask for the name of a lt site gt 100 file to write the values to Enter the site file name Enter the site file name without the 100 extension The user may name new lt gt 100 file to save these changes to Enter a new site filename to save changes to or return to save to original filename 100 5 1 8 XXXX 100 Backup File In the event that FILE100 should abort from the program at some point the user should attempt to locate the XXXX 100 backup file in the current directory This file should contain the orig
19. 10192 aug sanus ur usBnugiu jo san sjood ayy G aunBi4 15 H 2INVOHO OS 035405 N eHO 105 12301 41405 N 105 2701 L THNIN L uoneziEedauny Hy jenuu LIN LANL ame ja dua anys ud Jo Jadu E CLS Sa N ESNMWES 3HOH2IIN qov HNS EY T HOILVZIETIEV CJF 7 7 Dens DEus O HERLIN IYHNLOMHLS 2UIOBHWV LAW 2I IO HV LHIN 32v Juris AO 13H MO 14a 3294405 HOLLVXI3 H JILOIGIN AS NON fe ox urmBr q aP IFE DERESE EN i Jscscis N m owad 15 Y GUS Ase OTAOW AH 153A HvH LOHI H NOILYXI4 N JILOIBSIN AS rer Ol HOILVZIETLEV TOA 60 January 2001 CENTURY Tutorial SAL au 0 4405 yaya 510496 Jale aug sous ur sruaudsaud jo pue sood 8 7 aniJ E NERIS TATIANE 5 d 43H23 v T1 Oreo d 93911520 d2 2 z 3ENOS 935405 01
20. 56 to continue using the current weather data without rewinding Note that these choices 5 F C are fixed and may not be changed by the user Enter the comment Enter any comment desired up to 50 characters 40 CENTURY Tutorial January 2001 Once these questions have been answered the empty grid is displayed Block 1 Year 1 of 2 Start 1920 End 1950 Comment W F Jan Feb Mar Apr May Jun Jul Sep Oct Nov Dec TLST System commands FILL NEXT NXTA GOMT NXYR GOYR CPYR NBLK GBLK ABLK DBLK CBLK TIME PREV DRAW DRWA HELP SAVE QUIT Current date January of Year 1 User command The first line of the grid shows the current block the current year out of the total number of years to be set up in this block the block starting and ending years and the block s comment The possible event commands are listed along the left hand edge under the month line and the system commands are displayed along the bottom The last line displays the current month and year EVENT100 then waits for a response from the user Any event command entered at this time would be scheduled in the month currently shown The general format for entering a command is command lt addtl gt where command is one of the four letter commands and addtl is any additional information needed for that command In general an event command is undone by entering command X Text may be typed in either lower upper or mixed case EVENT100 will conver
21. Delimited radio button Then press the Next button to go to Step 2 In Step 2click on the Tab checkbox to remove the check mark next to the Tab option then click on the Space checkbox to select the Space option At this point you can select the Finish button Microsoft Excel will open your lis file parsing the output into columns with headings displaying the output variable names 6 3 Create a Graph of Your CENTURY Output in Microsoft Excel Save your lis file as a Microsoft Excel worksheet by selecting File Save As from the main menu Click on the down arrow to the right of the Save As Type text box Select the Microsoft Excel Workbook xls option from the drop down list If desired edit the filename in the File name text box Click the Save button The lis CENTURY output file will remain in your CENTURY directory Any changes you make to the output listing in Excel will not effect the lis output file 51 CENTURY Tutorial January 2001 To quickly graph all of the output data from your lis file listing select all of the data by clicking on the time variable name and holding down the Ctrl Shift keys while pressing the End key Select Insert Chart from the main menu or click on the Chart Wizard button in the Excel toolbar This will bring up the Chart Wizard In Step 1 of the Chart Wizard click on the Standard Types tab Select the XY Scatter option and click on the bottom right button in the Chart sub typ
22. If you want to use you own FC and WP values set swflag 1 and enter appropriate WP and FC values for awilt 1 10 and afiel 1 10 If you want to use an equation consult the Century User s Manual for the interpretation of different values of swflag we usually recommend swflag 2 1 CONTROLS ON PHOSPHORUS SORPTION Set the value for sorpmx to the maximum P sorption capacity for the soil 0 20 cm expressed as P sorbed m extreme values are 1 3 for sands and 10 20 for high sorption capacity clays sorpmx Set the value for pslsrb to the ratio between sorbed P and total sorbed labile P extreme values are 5 for sands to 95 for highly sorbing clays pslsrb Source for P sorption data LG s EXTERNAL NUTRIENT INPUT PARAMETERS The lt site gt 100 file includes parameters for atmosphereic N and S deposition described below Parameters controlling P and S inputs from weathering are in the fix 100 file 1 h NITROGEN Enter your best estimates for rates of nitrogen input below Atmospheric deposition wet dry gNm Non symbiotic biological N fixation g N m yr Symbiotic biological N fixation g N m Appendix 3 4 Appendix 3 For deposition and each input 1 Have input epnfa 1 epnfa 2 epnfs 1 epnfs 2 2 Have input epnfa 2 epnfa 1 epnfs 2 epnfs 1 l i SULFUR CENTURY Parameterization Workbook non symbiotic fixation you have two choices for be fixed constan
23. WOODIC C in WOODI dead fine branch component of forest system g m2 WOOD2C C in WOOD2 dead large wood component of forest system g m2 WOODSC C in WOOD3 dead coarse roots component of forest system g m2 WOODC Sum of in dead components of forest system g m2 Appendix 2 8 Appendix 2 CENTURY Output Variables by Category Nitrogen Output Variables AGLIVE 1 in aboveground live for grass crop g m2 AMINRL 1 Mineral N in layer 1 before uptake by plants BGLIVE 1 N in belowground live for grass crop g m2 N in forest system coarse root component g m2 CRPSTG 1 Retranslocation storage pool for grass crop g m2 EGRACC 1 Accumulator of N in grain tuber production for grass crop g m2 EGRAIN 1 Economic yield of N in grain tubers for grass crop g m2 ELIMIT Indicator of the limiting element 1 if N is the limiting element 2 if P is the limiting element 3 if S is the limiting element EPRODC 1 Actual monthly uptake for grass crop g m2 month EPRODFY 1 Actual monthly uptake in forest system g m2 month ERETA 1 Annual accumulator of N returned to system during grazing fire for grass crop g m2 year ERMVST 1 Amount of N removed as straw during harvest for grass crop g m2 month ESRSNK 1 source sink g m2 EUPACC 1 Growing season accumulator for N uptake by grass crop or tree g m2 1 Aboveground g
24. a tallgrass prairie Pages 353 370 in G Giovannozzi Sermanni and P Nannipieri editors Current perspectives in environmental biogeochemistry C N R I P R A Viterbo Italy 494 Palm C A M van Noordwijk P L Woomer J Alegre L Arevalo C Castilla D G Cordeiro K Hairiah J Kotto Same A Moukam W J Parton A Riese V Rodrigues and S M Sitompul Carbon losses and sequestration following land use change in the humid tropics American Society of Agronomy Special Publication submitted Parfitt R L B K G Theng J S Whitton and T G Shepherd 1997 Effects of clay minerals and land use on organic matter pools Geoderma 75 1 12 Parfitt R L 1995 Simulation of changes in soil organic matter and nutrient pools using the Century model for 1 the Puruki catchment and the Purutaka catchment for the last 85 years 2 Woodhill AK287 Manaaki Whenua Landcare Research PB 11052 Palmerston North Parton W J D S Schimel C V Cole and D S Ojima 1987 Analysis of factors controlling soll organic matter levels in Great Plains grasslands Soil Science Society of America Journal 51 1173 1179 465 Parton W J J W B Stewart and C V Cole 1988 Dynamics of C N P and grassland soils a model Biogeochemistry 5 109 131 472 Appendix 1 5 Appendix 1 Literature on CENTURY model Parton W J C V Cole J W B Stewart D S Ojima and D S Schimel 1989 Simulating regional patterns of soil C N and P dynamics i
25. cerfor 1 Simulate tissue chemistry as fixed with no retranslocation or response to nutrient availability Record the values for cerfor below C N C P c s VARIABLE EXPRESSION i 1 i 2 1 3 1 i litter conc 2 i root conc 3 i branch conc 4 i wood conc 5 i root conc Set all values for forrtf equal to O0 2 Use fixed tissue chemistry no response to nutrient availability but simulate retranslocation of nutrients from senescent leaves before litterfall Record the values for cerfor below C N C P c s VARIABLE EXPRESSION i 1 i 2 1 3 1 1 leaf conc 2 i root conc cerfor 50 fine 3 i branch conc 4 1 wood conc cerfor 50 coarse Set values for forrtf as forrtf 1 1 leaf litter forrtf 2 1 leaf litter P green lea green lea Fh Fh Fh o forrtf 3 1 leaf litter S green lea Appendix 3 19 Appendix 3 CENTURY Parameterization Workbook 3 Use both variable tissue chemistry and retranslocation Based on data from fertilization trials site comparisons literature and or educated guesses widen the allowable range for one or more of the biomass fractions Foliar N content has the most extensive data but this option can be implemented for any or all biomass pool s and nutrient s Assign the minimum C E ratio maximum nutrient content to cerfor 1 the maximum C E ratio minimum nutrient content to cerfor 2 and the init
26. continue to be shown until the user enters Q to quit or until the end of the option 1s reached 5 1 3 Changing an Option The user may change values of parameters within an existing option After entering 3 for changing the program will display each option which exists in the file and ask if the user would like to change that option Current option is W1 Wheat type one Is this an option you wish to change A response of Y or y will cause the program to move on to the change phase If no option 1s responded to with a yes answer the program will return to the previous menu of five actions Once an affirmative response has been given the user will be asked for a new abbreviation and description Enter a new abbreviation or a return to use the existing abbreviation A new abbreviation must be unique to that file and no more than 5 characters if a duplicate 1s entered the user will be asked to enter another abbreviation Enter a new description return to use the existing description The description may not be longer than 65 characters 29 CENTURY Tutorial January 2001 Then for each value in that option the program will display the existing value for that parameter and ask the user for a new value Commands F L lt new value return Name PRDX 1 Previous value 300 Enter response The user may enter any of these possible responses as shown on the Command line see the definition
27. current month Addtl The acceptable abbreviations come from the irri 100 file Mark IRRI Unmark IRRI X Output The year month and the word IRRI followed on the next line by the irrigation method selected GRAZ Schedules a grazing event in the current month Addtl The acceptable abbreviations come from the graz 100 file Mark GRAZ Unmark GRAZ X Output The year month and the word GRAZ followed on the next line by the grazing type selected ERODSchedules an erosion event in the current month The amount of soil loss kg m2 month Mark EROD amount Unmark EROD 0 Output The year month and the word EROD followed on the next line by the amount 48 CENTURY Tutorial January 2001 FIRE Schedules a fire in the current month Addtl The acceptable abbreviations come from the fire 100 file Mark FIRE addtl Unmark FIRE X Output The year month and the word FIRE followed on the next line by the type of fire selected TREE Selects a tree type Addtl The acceptable abbreviations come from the tree 100 file Mark TREE addtl Unmark TREE X Output The year month and the word TREE followed on the next line by the type of tree selected TREM Schedules a tree removal event in the current month Addtl The acceptable abbreviations come from the trem 100 file Mark TREM Unmark TREM X Output The year month and the word TREM followed on the next lin
28. day length while for drought deciduous systems leaf drop occurs when monthly soil water content is below the wilting point Typical values for wooddr 1 for are 0 95 for temperature deciduous and 0 3 for drought deciduous but use estimates that best represent your system 11 forest systems leafdr 1 leafdr 7 leafdr 2 leafdr 8 leafdr 3 leafdr 9 leafdr 4 leafdr 10 leafdr 5 leafdr 11 leafdr 6 leafdr 12 Sources for litterfall seasonality information Appendix 3 22 Appendix 3 CENTURY Parameterization Workbook 6 b ROOT AND WOOD DEATH RATES Turnover of other pools is constant through the year and is in the parameter wooddr Monthly fine root death rate wooddr 2 is equal to annual fine root production fine root biomass 12 Monthly fine branch death rate wooddr 3 is equal to annual f branch litterfall f branch biomass 12 Monthly large wood death rate wooddr 4 is equal to annual l wood litterfall l wood biomass 12 may also be estimated as approximately the rate of whole tree mortality per month Monthly coarse root death rate wooddr 5 is very difficult to estimate directly It is typically similar in magnitude to large wood death wooddr 3 Enter the value used here Sources 6 c LEAF AREA CONTROLS Set the leaf area to biomass ratio based on biomass not carbon btolai leaf area projected leaf dry mass m g S
29. each month In deciduous forests 80 of first month production goes to leaves and a given percentage of leaves senesce and fall at the end of the growing season which occurs when the days are shortening and temperatures are dropping into the fall seasonal range In a drought deciduous forest allocation is fixed throughout the year and a given percentage of leaves senesce and fall at the end of the growing season which is marked when the soil moisture reaches wilting point In general if the large majority of the canopy is deciduous say 80 or greater one of the deciduous system options will be adequate otherwise use the evergreen option For evergreen or semi evergreen systems decid 0 For deciduous systems decid 1 For drought deciduous systems decid 2 2 MAXIMUM PRODUCTION There are two maximum production values one for gross production and the other for net production Either of these can be disabled by setting it to a very high value e g 10000 and allowing the other to control production Maximum production is rarely directly observed in either the model or reality and must be inferred Maximum gross production This is expressed as the theoretical maximum gross production per month in terms of total organic matter produced NOT in terms of carbon Common values are 1200 1500 prdx 2 Appendix 3 17 Appendix 3 CENTURY Parameterization Workbook Maximum net production This is expres
30. for for surface metabolic litter METMNR 2 1 Net mineralization for N for soil metabolic litter MINERL 1 1 Mineral content for layer 1 g m2 MINERL 2 1 Mineral N content for layer 2 g m2 MINERL 8 1 Mineral content for layer 3 g m2 MINERL 4 1 Mineral N content for layer 4 g m2 MINERL 5 1 Mineral content for layer 5 g m2 MINERL 6 1 Mineral content for layer 6 g m2 MINERL 7 1 Mineral N content for layer 7 g m2 MINERL 8 1 Mineral N content for layer 8 g m2 Appendix 2 10 Appendix 2 CENTURY Output Variables by Category MINERL 9 1 Mineral content for layer 9 g m2 MINERL 10 1 Mineral content for layer 10 g m2 MINERL NLAYER 1 1 Deep storage layer for N leached NFIX Amount of symbiotic N fixation g m2 month NFIXAC Accumulator for amount of symbiotic N fixation g m2 month Parent material N g m2 RLEAVE 1 in forest system leaf component g m2 RLWODEX 1 N in forest system large wood component g m2 Mineral ratio used to control soil N fixation using a regression equation based on Kansas data SIMNR 1 1 Net mineralization for for surface microbes 1 1 1 SIMNR 2 1 Net mineralization for N for active pool SOM1E 2 1 S2MNR 1 Net mineralization for for slow pool SOM2E 1 SS3MNR 1 Net mineralization for for passive pool
31. for in your site 100 file If you have estimates of parent material P and S and atmospheric deposition of S you can use the following table to parameterize parent i and pparm i this scheme is not necessarily appropriate for detailed examination of long term P dynamics and pedogenesis First run the model for 3 years using mean weather and monthly output Calculate the average value of defac then complete Phosphorus Sulfur 1 2 3 Atmospheric deposition wet dry g m Literature source b Weathering inputs that occur within the rooting zone m Literature source source TOTAL INPUTS a b Po lt site gt 100 pparm 1 lt d e fix 100 Set the flag for texture effect on parent P mineralization for no effect TEXEPP 1 0 0 Sources for P and S input data Appendix 3 28 Appendix 4 CENTURY Command Lines CENTURY Command Lines Installing the PC Version of CENTURY The file cent40 exe 1s an installation file that will install CENTURY its associated utility programs sample parameter and schedule files and the Windows Help file version of the manual on your PC To run the installation file select Start Run from the Windows Start menu and use the Browse button to locate the cent40 exe file which you have downloaded Once you have located the cent40 exe file select the Run button to start the installation process and follow the instructions on the scree
32. for most crops 0 for grass 5 C E RATIOS CENURY allows for flexibility in the ranges of C E ratios as above ground biomass increases following parameters pramn i j and pramx i j control the maximum and minimum C E ratios P or S for shoots when plant biomass is above and below biomax The following table shows values that we have used for pramn and pramx biomax 400 for most grasses and crops See Fig 3 13 in the Century User s Manual ue unt m meer E T grass Ed ENERO mamas s s me fiso prama e 5 Appendix 3 13 Appendix 3 CENTURY Parameterization Workbook prbmn i j and prbmx i j control the minimum and maximum C E E P or S of roots We believe these parameters are mainly a function of plant type and commonly use a slope of 0 0 However users have the option of making C N of roots vary with precipitation see parameter definitions _ __ __ fo o_o emus e eene s s m emus ojo fo jefe emen fo a o_o 6 LIGNIN CONTENTS Ihe lignin content of above and below ground material can be constant or made a function of annual rainfall See parameter definitions This table shows values we have used Tall Winter Short 1 1 Soy Corn grass TA bean
33. have done one per line For example if you want to make two runs using the c3grs sch and c4grs sch schedule files and save the results to the c3grs bin and c4grs bin files respectively create the DOS batch file as follows century s c3grs n c3grs century s c4grs n c4grs Save the DOS batch file with a bat extension To run the DOS batch file type the DOS batch filename at the DOS prompt For example if you have saved your DOS batch file as century bat to run it you would type century bat at that DOS prompt in your run directory NOTE Each binary file that you have CENTURY create must have a unique filename and the file must not exist in the run directory prior to executing the batch file 64 CENTURY Tutorial January 2001 8 3 Combining the Above Options You can combine the two options listed above to further automate CENTURY runs Use a DOS batch file and the command line parameter option for LIST100 to do CENTURY runs and create ASCII output files for the runs The CENTURY command lines and the LIST100 command lines should be entered into the DOS batch file on separate lines one per line The LIST100 command lines must follow the CENTURY command lines For example century s c3grs n c3grs 1151100 c3grs c3grs list txt century s c4grs n c4grs list100 c4grs c4grs var_list txt The following events will occur when running this batch file 1 CENTURY will run using the c3grs sch schedule file and it will create a bin
34. large wood component g m2 y CPRODA Annual accumulator of C production in crop grassland forest net primary production g m2 year CPRODF Total monthly forest C production g m2 month CROOTC C in forest system coarse root component g m2 CRTACC Growing season accumulator for C production in forest system coarse root component g m2 y CRTCIS 1 Unlabeled C in forest system coarse root component g m2 CRTCIS 2 Labeled C in forest system coarse root component g m2 Appendix 2 6 Appendix 2 CENTURY Output Variables by Category FBRACC Growing season accumulator for C production in forest system fine branch component g m2 y FBRCHC in forest system fine branch component g m2 FBRCIS 1 Unlabeled C in forest system fine branch component g m2 FBRCIS 2 Labeled C in forest system fine branch component g m2 FCACC Growing season accumulator for C production in forest system g m2 y FROOTC C in forest system fine root component g m2 FRSTC Sum of C in forest system live components RLEAVC FROOTC FBRCHC RLWODC CROOTO g m2 FRTACC Growing season accumulator for C production in forest system fine root component g m2 FRTCIS 1 Unlabeled C in forest system fine root component g m2 FRTCIS 2 Labeled C in forest system fine root component g m2 FSYSC Total C forest system 1 sum of soil organic matter trees dead wood forest litter RLEAVC
35. m2 CLTFAC 1 Effect of cultivation on decomposition for SOM1 CLTEFF 1 if cultivation occurs in the current month 1 otherwise CLTFAC 2 Effect of cultivation on decomposition for SOM2 CLTEFF 2 if cultivation occurs in the current month 1 otherwise CLTFAC 8 Effect of cultivation on decomposition for SOM3 CLTEFF 3 if cultivation occurs in the current month 1 otherwise CLTFAC 4 Effect of cultivation on decomposition for structural CLTEFF 4 if cultivation occurs in the current month 1 otherwise CSRSNK 1 Unlabeled C source sink g m2 CSRSNK 2 Labeled C source sink g m2 DBLIT Delta 13C value for belowground litter for stable 1sotope labeling DMETC 1 Delta 13C value for metabolic surface C for stable isotope labeling DMETC 2 Delta 13C value for metabolic soil C for stable isotope labeling DSLIT Delta 13C value for surface litter for stable 1sotope labeling DSOMIC 1 Delta 13C value for SOM1C 1 for stable isotope labeling DSOMI1C 2 Delta 13C value for SOM1C 2 for stable isotope labeling DSOM2C Delta 13C value for SOM2C for stable isotope labeling DSOMSC Delta 13C value for for stable isotope labeling DSOMSC Delta 13C value for soil organic matter for stable isotope labeling DSOMTC Delta 13C value for total soil C for stable isotope labeling DSTRUC 1 Delta 13C value for surface structural C for stable isotope labeling Appendix 2 18
36. of that parameter enter D find a specific parameter in that enter F see a help message enter H list the next 12 parameters 00000 01001 enter L quit retaining the old values for this and the remaining parameters im thissOption Si enter Q take the old value J 2 enter return entera new value enter a new value The command and previous value lines will continue to be shown until the user enters Q to quit or until the end of the file is reached Finally the user 1s asked if changes made should be saved Do you want to save the changes made MU UN If this is answered with y or Y the changed values will be saved Otherwise the changes will be lost 5 1 4 Changing the lt site gt 100 File Making changes to the lt site gt 100 file is different in that the parameters in this file are subdivided for easier review After selecting lt site gt 100 from the main menu enter the name of the site file without the 100 extension The user may name a new lt site gt 100 file to save these changes to Enter a new site filename to save changes to or a return to save to original filename 100 The program will then display the existing abbreviation and description and allows the user to provide new ones Enter a new abbreviation or a return to use the existing abbreviation Enter an abbreviat
37. potential in Rocky Mountain tundra and forest implications for aquatic systems Biogeochemistry 27 61 82 698 Bradley R I and T R Mayr Modelling soil organic matter change in English and Welsh soils using the CENTURY model In prep Bromberg J G R McKeown L Knapp T G F Kittel D S Ojima and D S Schimel 1996 Integrating GIS and the CENTURY model to manage and analyze data Pages 429 431 in GIS and Environmental Modeling Progress and Research Issues Burke I C D S Schimel C M Yonker W J Parton L A Joyce and W K Lauenroth 1990 Regional modeling of grassland biogeochemistry using GIS Landscape Ecology 4 45 54 573 Burke I C T G F Kittel W K Lauenroth P Snook C M Yonker and W J Parton 1991 Regional analysis of the Central Great Plains sensitivity to climate variability Bioscience 41 685 692 628 Burke I C W K Lauenroth W J Parton and C V Cole 1994 Interactions of landuse and ecosystem structure and function a case study in the Central Great Plains Pages 19 95 in G E Likens and P M Groffman editors Integrated regional models interactions between humans and their environment Chapman and Hall New York New York USA Carter M R W J Parton I C Rowland J E Schultz and G R Steed 1993 Simulation of soil organic carbon and nitrogen changes in cereal and pasture systems of Southern Australia Australian Journal of Soil Research 31 481 491 662 Cole C V I C Burke W J P
38. rces1 1 i a 2 0 ema eed 97 Sources for soil nutrient data 3 55 INITIAL PARAMETERS This parameterization is not necessary for annual grasses or crops and is only necessary for perennial grasses and crops if ivauto 0 you are simulating a forest or perennial grass or crop proper initialization of these pools is not essential if you include an equilibrium block in your schedule file If you have biomass and nutrient concentration estimates and want to set initial conditions calculate as indicated below Appendix 3 8 Appendix 3 CENTURY Parameterization Workbook 3 a GRASS CROP ORGANIC MATTER INITIAL PARAMETERS Carbon pools if you have actual carbon data rather than just biomass use them BIOMASS FRACTION EXPRESSION VARIABLE VALUE aboveground biomass 0 50 aglcis 1 Set all the corresponding cis 2 pools to 0 0 if you are not simulating isotope labeling Nutrient pools P and S calculations are necessary only if nelem 2 or 3 Calculate each as biomass concentration N P S FRACTION VARIABLE i 1 2 i 3 belowground bgliv i 3 b FOREST ORGANIC MATTER INITIAL PARAMETERS Carbon pools if you have actual carbon data rather than just biomass use them BIOMASS FRACTION EXPRESSION VARIABLE VALUE COARSE ROOT biomass 0 50 crtcis 1 EI Set all the corresponding cis 2 pools to 0 0 if you are not simulating isotope labeling Appendix 3 9 Appe
39. selected output variables from the binary file produced by a CENTURY run To run LIST100 enter the following command line at the DOS prompt in your working directory 1151100 and follow the on screen prompts For example to create an ASCII text file called yields lis of variables from the testrun bin file type 115100 List100 Binary to Ascii Utility Enter name of binary input file no bin Type testrun to indicate the testrun bin file Enter name of ASCII output file no lis Type yields to indicate that the name of the new output file is to be yields lis Enter starting time return for time file begins Type return or a year Enter ending time return for time file ends Type return or a year Enter variables per line return to quit Type crmvst return cgrain return lt return gt to indicate that these two variables in addition to the time should be written to the ASCII file Execution success Typing dir will show that the 18 file has been created The testrun bin file still exists and LIST100 may be used again to create another ASCII text file from the CENTURY binary output 50 CENTURY Tutorial January 2001 6 Viewing CENTURY Output Listing from LIST100 6 1 Using a text editor The lis output file created by LIST100 can be viewed using any text editor such as DOS Edit or Windows Notepad or word processor such as Microsoft Word or Word Perfect
40. 00 file there may be several cultivation options defined such as plowing or rod weeder For each option the parameters are defined to simulate that particular option Each data input file is named with a 100 extension to designate it as a CENTURY file These files can be updated and new options created through the FILE100 program The timing variables and schedule of when events are to occur during the simulation are maintained in the schedule file named with a sch extension This file can be created and updated through the EVENT100 program 20 January 2001 CENTURY Tutorial NISMS aut pue suueJBoud diusuane a4 aug AMOI NAS 241 euep ajl 0019 113 pue 5 Feels JUERO 108 540 45 25 OOLLSIT 00LLN3A3 21 CENTURY Tutorial January 2001 When running CENTURY the directory from which you will be running your simulations must contain the following files century exe the CENTURY executable The parameter files these files contain options which used by the schedule file to set the values for the events in your simulation The files crop 100 cult 100 fert 100 fire 100 graz 100 harv 100 irri 100 omad 100 tree 100 trem 100 can have one or many options in the file The option from the file that will be used in your mode
41. 06 0 8 1 12 14 h Figure 1 3 Impact of sail temperature a and rainfall b on decomposition January 2001 CENTURY Tutorial 15 Jaseg DE FEX TO NOLYZTILY TOA Girona dad SXUA 0150434 J3IH3HdSOlN I Y zig 2r TOSV LIN 138 HOILLVXI3 2ILOIBIN AS T38 qov FANS apatugns 10 15 3H2v11 JES qzw HNS DEJ PL anfi 1032405 FINOS 035 0 105 2301 231N05 N 110 uoneziEeJauny NAN jenuu LIN LINL UDEA ame dura Jo 10 pu IN EF 6 18 O HS ISN Lond 15 2I TOSY L3IN J a abem bF aes ies DATES SATE Ne N owad ZI BIO 15 Far og HOILVZLTLLV TOA 5 32v duris NWO opel USA MWe Te AOI January 2001 CENTURY Tutorial sruaudsaud aug 49 Moj 5 ENSIS THINN rnmaoo 03920 inr d
42. 2 fixed g C NPP 10 DOUBLED CO PARAMETERS CENTURY allows simulations to be conducted assuming a doubling of atmospheric CO concentration from 350 ppm to 700 ppm The following parameters control the effects of doubled CO on NPP transpiration C E ratios and root shoot ratios co2ipr 1 is the multiplier that represents the effect of doubled CO on NPP co2ipr 1 1 for C4 and 1 3 for C3 co2itr 1 is the multiplier that represents the effect of doubled CO on transpiration rate co2itr 1 0 6 co2ice 1 i j is the multiplier that represents the effect of doubled CO on minimum and maximum C E ratios co2ice 1 i j 1 0 co2irs 1 is the multiplier that represents the effect of doubled CO on root shoot ratio co2irs 1 lt 1 3 Appendix 3 16 Appendix 3 CENTURY Parameterization Workbook tree 100 The CENTURY installation package contains tree 100 parameterizations for deciduous coniferous and tropical systems that have been used in the past suggest that you use one of those files as a starting point and use the following procedure to modify parameters as needed to represent the trees in your particular system See Appendix 2 10 in the Century User s Manual for definitions of the parameters in this file 1 FOREST TYPE Decide whether to simulate your forest as evergreen deciduous or drought deciduous In evergreen systems allocation is fixed through the year and leaf fall is calculated
43. 5 941 950 Rasmussen P E and W J Parton 1994 Long term effects of residue management in wheat fallow I Inputs yield and soil organic matter Soil Science Society of America Journal 58 523 530 694 Ruimy Field D Herbert Kelly McMurtrie W J Parton L L Pierce and CMEAL participants Forest and grassland responses to elevated atmospheric CO2 resource use factors from four ecosystem models Ecological Applications submitted Ryan MeMurtrie G I Hunt Jr J D Aber A D Friend Rastetter and W M Pulliam 1996 Comparing models of ecosystem function for temperate conifer forests II Simulations of the effect of climate change Pages 263 387 in A I Breymeyer D O Hall J M Melillo and G I ren editors Global change effects on coniferous forests and grasslands SCOPE volume 56 John Wiley amp Sons Chichester West Sussex England Sanford R L Jr W J Parton D S Ojima and D J Lodge 1991 Hurricane effects on soil organic matter dynamics and forest production in the Luquillo Experimental Forest Puerto Rico results of simulation modeling Biotropica 23 364 372 630 Schiere M 2000 Soil fertility on Linosa quantifying the changes in soil organic matter on the semi arid Mediterranean island of Linosa Dissertation Wageningen Agricultural University Firenze Italy Schimel D S W J Parton T G F Kittel D S Ojima and C V Cole 1990 Gr
44. A 5 E 5 50440 5 1 34 20109413 9 snp aug sani 1004 au 474 SROs 28 8405 2198 405 SoS proc E30 uanEzyE aun z JEn uu CE NLS NL an padua TAIN BIW Los para 10 py Ce 5 Iraans fe 4 5 5 5 Irans ope abep bry 93 Ie IVA ON JH 1 82909015 5 imn 30 5 62 CENTURY Tutorial January 2001 8 Advanced Options 8 1 Run LIST100 Using Command Line Parameters LIST100 can be run using command line parameters and an ASCII text input file This option is useful if you want to look at the same output parameters for several runs It can be especially useful when you have a long list of output parameters that you wish to extract from the CENTURY binary output file Use the following command line to run LIST100 using command line parameters 1151100 binary filename list filename variables filename start time end time The binary filename refers to the bin file that CENTURY creates The list filename is the name of the file that you want LIST100 to create The variables filename is an ASCII text file tha
45. CENTURY Tutorial Supplement to CENTURY User s Manual Bill Parton Dennis Ojima Steve Del Grosso Cindy Keough Table of Contents CENTURY Model Overview 1 1 Introduction 12 CENTURY Model Description 1 3 Organic Matter Model 1 4 Water and Temperature Model 1 5 Plant Production and Management Model 1 6 Use and Testing of the CENTURY Model 1 7 DAYCENT Model Description Downloading and Installing the PC Version of CENTURY CENTURY Associated Files and Utility Programs Preparing for a CENTURY Simulation Running CENTURY and its Utility Programs 5 1 FILE100 5 1 1 Reviewing All Options 5 1 2 Adding an Option 5 1 3 Changing an Option 5 1 4 Changing the lt site gt 100 File 5 1 5 Deleting an Option 5 1 6 Comparing Options 5 1 7 Generating Weather Statistics 5 1 8 XXXX 100 Backup File 5 2 EVENT100 5 2 1 The Concept of Blocks 5 2 2 Defaults and Old Values 5 2 9 What EVENT100 Needs 5 2 4 Using EVENT100 5 2 5 Explanation of Event Commands 5 2 6 Explanation of System Commands 5 2 7 The 1 Option Reading from a Previous Schedule File 5 3 CENTURY 5 4 LIST100 Viewing CENTURY Output Listing from LIST100 6 1 Using a text editor 6 2 Using Microsoft Excel 6 8 Create a Graph of Your CENTURY Output in Microsoft Excel CENTURY Output Variables 12 15 16 18 20 24 26 27 28 28 29 32 32 38 34 35 36 37 42 45 48 49 51 51 51 51 54 Advance
46. D J S Baron D S Ojima and W Parton 1997 The effects of land use and temperature change on ecosystem processes in the South Platte River Basin Supplement to Bulletin of the Ecological Society of America Vol 78 Holland E A W J Parton J K Detling and D L Coppock 1992 Physiological responses of plant populations to herbivory and their consequences for ecosystem nutrient flow American Naturalist 140 685 706 647 Howard P J A P J Loveland R I Bradley F T Dry D M Howard and D C Howard 1995 The carbon content of soil and its geographical distribution in Great Britain Soil Use and Management 11 9 15 Thori T I C Burke W K Lauenroth and D P Coffin 1995 Effects of cultivation and abandonment on soil organic matter in Northeastern Colorado Soil Science Society of America Journal 59 1112 1119 Jackson R B H J Schenk E G Jobbagy J Canadell G D Colello R E Dickinson T Dunne C B Field P Friedlingstein M Heimann K Hibbard D W Kicklighter A Kleidon R P Neilson W J Parton O E Sala and M T Sykes Belowground consequences of vegetation change and its treatment in models Ecological Applications submitted Keating B A I Vallis W J Parton V R Catchpoole R C Muchow and M J Robertson 1994 Modelling and its application to nitrogen management and research for sugarcane Pages 131 142 in Proceedings of Australian Society of Sugar Cane Technologists 707 Kelly R H I C Burk
47. E and g m2 SOMTE 3 Total S in soil organic matter including belowground structural metabolic STDEDE 8 5 in standing dead for grass crop g m2 Appendix 2 23 Appendix 2 CENTURY Output Variables by Category STREAM 4 5 from mineral leaching of stream flow base flow storm flow g m2 STREAM 8 S from organic leaching of stream flow base flow storm flow g m2 STRMNR 1 3 Net mineralization for S for surface structural litter STRMNR 2 3 Net mineralization for S for soil structural litter STRUCE 1 3 Surface litter structural S g m2 STRUCE 2 3 Soil litter structural 5 g m2 SUMNRS 8 Annual accumulator for net mineralization of S from all compartments except structural and wood g m2 y TCERAT 8 Total C S ratio in soil organic matter including belowground structural metabolic TEREM 8 Total S removed during forest removal events g m2 TMINRL 3 Total mineral S summed across layers g m2 TNETMN 3 Annual accumulator of net mineralization for S from all compartments g m2 y TOTALE 8 Total S including source sink W1MNR 8 S mineralized from the WOOD1 dead fine branch component of a forest system g m2 W2MNR 3 S mineralized from the WOOD2 dead large wood component of a forest system g m2 W3MNR 3 S mineralized from WOODS dead coarse root component of a forest system g m2 WOODIE 3 WOOD1 dead fine branch
48. IL CARBON POOLS This parameterization is necessary only if ivauto 0 Two procedures are described one for grassland cropped soils and one for forest soils Choose the appropriate procedure but note that precise initialization of these pools is not necessary if your schedule file includes an equilibrium block Grassland cropped soils Enter the initial litter and soil carbon storages Enter total in top 20 cm Subdivisions by pedogenic horizons are not required but may help set apportioning to CENTURY SOM pools Observed soil carbon storages a Litter g C m b Mineral soil g C m c TOTAL a b g Cm Calculate apportioning of SOM into CENTURY pools I Based on simple horizons 2 2 somlci 2 1 som2ci 1 som3ci 1 clittr 1 1 ee MM ens qe oo M poe a Appendix 3 6 Appendix 3 CENTURY Parameterization Workbook Forest soils Enter the initial forest floor and soil carbon storages For mineral Soil enter total in top 20 cm for organic soils enter 0 20 cm totals as forest floor divided by horizons Forest floor excludes woody debris This parameterization can be done using simple horizons or subhorizons Observed soil carbon storages Simple Horizons Sub Horizons a Forest floor C m al layer 01 a2 H layer 02 b Mineral soil C m bl A b2 B Bt E b3 Bh c TOTAL a b g Cm Calculate apportioning of SOM into CENTURY pools I Based on simple hori
49. MOSIB BASEF L Figure 7 5 January 2001 SHOW SNOW PET EN BARE SOIL EVAPORATION Atmosphere TRANSPIRATION TRAM AB Aboveground Biomass 9 m LE AF Live Leaf Biomass 9 PET Monthly Potential Evapotranspi ration crm PRECIP Precipitation cm Average Air Temperature CT STORMF Storm Flow BASEF Base Flow AVH20 2 Available HO in 60 depth 20 3 Available HO in plant rooting depth em Flow diagram far the water submodel The structure represents model set up to operate with NLAYER set to 5 58 January 2001 CENTURY Tutorial 0 1402 540426 aug says ur uagaea sso pue sjood au e sani WE 3 25405 ONL 5 3 DINOS SINT patre H HOV T1 aane redu mysmia 10 adn Dens 3 OOS 2 380 2IIN rey iX 2 2 2 nod owo T3 WO 38 jov duris 3374 uris agg a 2 apua g sjuargn y 2 ame janua 15 cd 59 January 2001 CENTURY Tutorial sag aul p quna
50. NCENTURY Use the dir command ensure that you are in the correct directory If you enter the command dir exe you should the CENTURY executable and its utility programs listed Appendix 4 1 Appendix 4 CENTURY Command Lines century exe event100 exe file100 exe list100 exe The usual sequence of events when running CENTURY 1 Create the desired parameterizations in the 100 files using FILE100 Use 00 to create the schedule file for your simulation Run the CENTURY simulation Use LIST100 to extract the desired output from the binary output file produced by your CENTURY run FILE100 The FILE100 program 1s designed to help the user create new options or change values in existing options in any of the 100 data files used with EVENT100 and CENTURY This utility also provides parameter definitions units and valid values or ranges To run FILE100 make sure the executable program file100 exe the 100 data files and the def parameter definition files are in the same directory To start the program enter file100 at the DOS prompt and follow the on screen menus EVENT100 EVENT 100 is the scheduling preprocessor for the CENTURY Soil Organic Matter Model This preprocessor allows the user to schedule management events and crop growth controls at specific times during the simulation and produces an ASCII output file which is read in by CENTURY EVENT100 uses a grid like display to allow
51. NRS 1 Annual accumulator for net mineralization of N from all compartments except structural and wood g m2 y 1 Total C N ratio in soil organic matter including belowground structural metabolic TCNPRO Total C N ratio for grass crop or tree production TEREM 1 Total N removed during forest removal events g m2 TMINRL 1 Total mineral N summed across layers g m2 TNETMN 1 Annual accumulator of net mineralization for N from all compartments g m2 y TOTALE 1 Total N including source sink VOLEX Volatilization loss as a function of mineral N remaining after uptake by grass crop or tree g m2 VOLEXA Accumulator for N volatilization as a function of N remaining after uptake by grass crop or tree total N for entire simulation g m2 VOLGM Volatilization loss of N as a function of gross mineralization Appendix 2 12 Appendix 2 CENTURY Output Variables by Category VOLGMA Accumulator for N volatilized as a function of gross mineralization total N for entire simulation g m2 VOLPL Volatilization of N from plants during harvest for grass crop VOLPLA Accumulator for N volatilized from plant at harvest for grass crop total N for entire simulation g m2 W1MNR 1 N mineralized from the WOOD dead fine branch component of a forest system g m2 W2MNR 1 N mineralized from the WOOD2 dead large wood component of a forest system g m2 W3MNR 1 N mineral
52. TE 2 FBRCHE 2 RLWODE 2 CROOTE 2 g m2 FSYSE 2 Total P in forest system i e sum of soil organic matter trees dead wood forest litter GROMIN 2 Gross mineralization of P LHZEAC 2 Accumulator for P inputs to 0 20 cm layer from the lower horizon pools associated with soil erosion g m2 1 2 Metabolic P in surface litter g m2 METABE 2 2 Metabolic P in soil litter g m2 METMNR 1 2 Net mineralization for P for surface metabolic litter METMNR 2 2 Net mineralization for P for soil metabolic litter MINERL 1 2 Mineral P content for layer 1 g m2 MINERL 2 2 Mineral P content for layer 2 g m2 MINERL 8 2 Mineral P content for layer 3 g m2 MINERL 4 2 Mineral P content for layer 4 g m2 MINERL 5 2 Mineral P content for layer 5 g m2 MINERL 6 2 Mineral P content for layer 6 g m2 MINERL 7 2 Mineral P content for layer 7 g m2 MINERL 8 2 Mineral P content for layer 8 g m2 9 2 Mineral P content for layer 9 g m2 Appendix 2 15 Appendix 2 CENTURY Output Variables by Category MINERL 10 2 Mineral P content for layer 10 g m2 MINERL NLAYER 1 2 Deep storage layer for P leached OCCLUD Occluded P g m2 PARENT 2 Parent material P g m2 PLABIL Accumulator of labile phosphate in all layers RLEAVE 2 P in forest system leaf component g m2 RLWODE 2 in forest system large wood component g m2
53. URY Tutorial January 2001 After entering up to five options the differences between the options are displayed For example the differences between two wheat crops may be Difference Abbrev Name Value W2 HIMAX 0 35 W3 HIMAX 0 42 Difference Abbrev Name Value W2 EFRGRN 1 0 65 W3 1 0 75 Note that format differences are not displayed There is no difference for example between 1 00 and 1 After four differences are displayed on the screen the user may continue to see more differences if they exist or quit Hit lt return gt to continue Q to quit 5 1 7 Generating Weather Statistics If the user has access to actual weather data for a minimum ten year period those weather values may be used to generate precipitation means standard deviations and skewness values minimum temperature means and maximum temperature means These statistical values can then be used to drive the stochastic weather generator in CENTURY These statistical values are maintained in the lt site gt 100 file The name of the actual weather file must have a maximum of eight characters with a wth extension The format of the file is the standard format as required by CENTURY a four character name field prec tmin or tmax two spaces a four character year field 12 number fields of the format 7 2 such that the length of each line is 94 characters For example prec 1915 0 31 255 5 07 1101 8 87 553 1 61 8 83 B55 3253 0 99
54. abeled CO2 respiration from decomposition g m2 Appendix 2 2 Appendix 2 CENTURY Output Variables by Category RESP 2 Annual labeled CO2 respiration from decomposition g m2 11C2 1 Accumulator for unlabeled CO2 loss due to microbial respiration during soil organic matter decomposition of surface SOM1 to SOM2 11C2 2 Accumulator for labeled CO2 loss due to microbial respiration during soil organic matter decomposition of surface SOM1 to SOM2 21C2 1 Accumulator for unlabeled CO2 loss due to microbial respiration during soil organic matter decomposition of soil SOM1 to SOM2 and SOM3 21C2 2 Accumulator for labeled CO2 loss due to microbial respiration during soil organic matter decomposition of soil SOM1 to SOM2 and SOM3 2C2 1 Accumulator for unlabeled CO2 loss due to microbial respiration during soil organic matter decomposition of SOM2 to soil SOM1 and SOM3 52 2 2 Accumulator for labeled CO2 loss due to microbial respiration during soil organic matter decomposition of SOM2 to soil SOM1 and SOMS 3C2 1 Accumulator for unlabeled CO2 loss due to microbial respiration during soil organic matter decomposition of SOMS to soil SOM1 3C2 2 Accumulator for labeled CO2 loss due to microbial respiration during soil organic matter decomposition of to soil SOMI ST1C2 1 Accumulator for unlabeled CO2 loss due to microbial respiration during litter decomposition of surface structural into SOM1 a
55. additional it is simply marked or unmarked Mark FRST Unmark FRST Output The year month and the word FRST LAST Marks the current month as the last month of growing for crops Addtl This command has no additional it is simply marked or unmarked Mark LAST Unmark LAST Output The year month and the word LAST SENMMarks the current month as the month of senescence for crops Addtl This command has no additional it is simply marked or unmarked Mark SENM Unmark SENM Output The year month and the word 42 CENTURY Tutorial January 2001 FERT Schedules a fertilization event in the current month Addtl The acceptable abbreviations come from the fert 100 file Mark FERT addtl Unmark FERT X Output The year month and the word FERT followed on the next line by the fertilization method selected CULT Schedules a cultivation event in the current month Addtl The acceptable abbreviations come from the cult 100 file Mark CULT addtl Unmark CULT X Output The year month and the word CULT followed on the next line by the cultivation method selected OMADSchedules an organic matter addition event in the current month Addtl The acceptable abbreviations come from the omad 100 file Mark OMAD addtl Unmark OMAD X Output The year month and the word followed on the next line by the type of organic matter addition selected IRRI Schedules an irrigation event in the
56. alue eese enter a new value The command and previous value lines will continue to be shown until the user enters Q to quit or until the end of the subheading is reached 31 CENTURY Tutorial January 2001 After selecting choice 0 Return to the main menu from the subheadings menu the user is asked 1f the changes made should be saved Do you want to save the changes made MU UN If this is answered with y or Y the changed values will be saved Otherwise the changes will be lost 5 1 5 Deleting an Option The user may choose to delete one or more options from that 100 file After entering 4 for delete each abbreviation and description of each option found is shown Current option is W1 Wheat type one Is this an option you wish to delete If the user responds with a Y a double check is made to insure that no error was made Are you sure you want to delete W1 Wheat type one If the answer 16 again Y or y the option 1s completely deleted from the 100 file and is not recoverable 5 1 6 Comparing Options The user may choose to compare options from that 100 file After entering 5 for compare all abbreviations found in the file are shown WI W2 We G1 G2 G4 G5 SYBN Current limit of options to compare is 5 The user is then asked to enter all of the options up to 5 that should be compared at one time Enter an option to compare lt return gt to quit 32 CENT
57. and complete the table DEBRIS COMPONENT TURNOVER TIME yr EXPRESSION decw FINE BRANCH 2 5 turnover 1 defac LARGE WOOD 2 5 turnover decw2 defac BELOWGROUND 2 5 turnover decw3 defac anerb 5 BIOMASS AND WOODY DEBRIS BIOMASS AND NPP DATA Enter below your best estimates for biomass pool sizes chemistry annual production and turnover comments on estimating values follow BIOMASS NPP LITTER FRACTION g m g m SN LEAF XXXXXXX LITTER XXXXXXX XXXXXXX COARSE ROOT FINE ROOT Large wood is branch and stem wood 10 cm diameter Fine roots are 2 mm diameter Measured wood litterfall collected in traps usually indicates fine branch litterfall and can be used as an estimate of fine branch production in older forests Large wood litterfall is rarely measured and must be estimated from guesses about turnover time and tree longevity Coarse root production is likewise rarely measured often even biomass data are lacking Educated guesses as to biomass and turnover rates must be used in these cases Sources for biomass and production data Appendix 3 21 Appendix 3 CENTURY Parameterization Workbook 5 b PRODUCTION ALLOCATION PATTERN CENTURY allows for different C allocation patterns for juvenile and mature forests Age indicator i is 1 for early forest 2 for late forest If you are simulating only 1 types of forest set s
58. art year 0 End year 1899 Output starting year 1800 Output month 9 Output interval 1 Then the simulation might initiate an agricultural agent and examine seasonal trends with monthly output Start year 1900 End year 1919 Output starting year 1900 Output month 1 Output interval 0 0833 The weather choice may also be different in each block The user should not only consider the events but also the output file requirements and weather source changes when determining what blocks a particular simulation will consist of 5 2 2 Defaults and Old Values Where a default or old value is shown the user may accept this value by merely hitting the Enter key Any other value should be explicitly entered by typing it in 36 CENTURY Tutorial January 2001 5 2 3 What EVENT100 Needs run the EVENT100 event scheduler the user will need the EVENT100 executable program and the twelve 100 data files EVENT100 uses these data files to limit the user s entries to those that exist Therefore the user should set up any necessary options of specific 100 file entries before beginning work in EVENT100 5 2 4 Using EVENT100 To use EVENT100 make sure that the executable program event100 exe and the 100 data files are in the same directory To start the program enter event100 at the DOS prompt After showing the program title several initial questions need to be answered CENTURY Events Scheduler Enter the name of the
59. arton D S Schimel D S Ojima and J W B Stewart 1988 Analysis of historical changes in soil fertility and organic matter levels of the North American Great Plains Pages 436 438 in Challenges in dryland agriculture a global perspective Proceedings of the International Conference on Dryland Farming Amarillo Bushland Texas USA 570 Cole C V J W B Stewart D S Ojima W J Parton and D S Schimel 1989 Modelling land use effects of soil organic matter dynamics in the North American Great Plains Pages 89 98 in M Clarholm and L Bergstr m editors Ecology of arable land Kluwer Academic Publishers Amsterdam Netherlands 554 Cole C V K Paustian E T Elliott A K Metherell D S Ojima and W J Parton 1993 Analysis of agroecosystem carbon pools Water Air and Soil Pollution 70 357 371 660 Appendix 1 1 Appendix 1 Literature on CENTURY model Crist T O and J A Williams Simulation of topographic and daily variation in colony activity of Pogonomyrmex Occidentalis Hymenoptera Formicidae using a soil temperature model Environmental Entomology submitted Del Grosso S J W J Parton Mosier D S Ojima C S Potter W Borken R Brumme K Butterbach Bahl Crill K Dobbie and Smith 2000 General oxidation model and comparisons of CH4 oxidation in natural and managed systems Global Biogeochemical Cycles 14 999 1019 Del Grosso S J W J Parton A R Mosier D S Ojima Ku
60. ary output file named c3grs bin 2 LIST100 will run extracting output values from the c3grs bin file and creating the c3grs lis ASCII file using the list of variable names in the var list txt file 3 CENTURY will run using the c4grs sch schedule file and it will create a binary output file named c4grs bin 4 LIST100 will run extracting output values from the c4grs bin file and creating the c4grs lis ASCII file using the list of variable names in the list txt file The DOS batch file could also be created as century s c3grs n c3grs century s c4grs n c4grs list100 c3grs c3grs var_list txt list100 c4grs c4grs var_list txt The order of event execution in this case will be as follows 1 CENTURY will run using the c3grs sch schedule file and it will create a binary output file named c3grs bin 2 CENTURY will run using the c4grs sch schedule file and it will create a binary output file named c4grs bin 3 LIST100 will run extracting output values from the c3grs bin file and creating the c3grs lis ASCII file using the list of variable names in the var list txt file 4 LIST100 will run extracting output values from the c4grs bin file and creating the c4grs lis ASCII file using the list of variable names in the var list txt file 65 CENTURY Tutorial January 2001 66 Appendix 1 Literature on CENTURY model Literature on CENTURY model Baron J D S Ojima E A Holland and W J Parton 1994 Analysis of nitrogen saturation
61. assland biogeochemistry links to atmospheric processes Climatic Change 17 13 25 592 Schimel D S T G F Kittel and W J Parton 1991 Terrestrial biogeochemical cycles global interactions with the atmosphere and hydrology Tellus 43A B 188 203 620 Schimel D S T G F Kittel D S Ojima F Giorgi Metherell Pielke Cole and J G Bromberg 1994 Models methods and tools for regional models of the response of ecosystems to global climate change Pages 227 238 in R C Wood and J Dumanski editors Proceedings international workshop on sustainable land management for the 21st century Agricultural Institute of Canada Ottawa Schimel D S Braswell E A Holland McKeown D S Ojima T H Painter W J Parton and A R Townsend 1994 Climatic edaphic and biotic controls over storage and turnover of carbon in soils Global Biogeochemical Cycles 8 279 293 710 Appendix 1 8 Appendix 1 Literature on CENTURY model Schimel D S B H Braswell R McKeown D S Ojima W J Parton and W Pulliam 1996 Climate and nitrogen controls on the geography and timescales of terrestrial biogeochemical cycling Global Biogeochemical Cycles 10 677 692 Seastedt T R C C Coxwell D S Ojima and W J Parton 1994 Controls of plant and soil carbon in a semihumid temperate grassland Ecological Applications 4 344 353 Smith P J U Smith D S Powlson J R M Arah O G Chertov K Coleman U Franko S Frol
62. atio material The nutrient content of structural material is quite low and nutrients are immobilized into microbial biomass during decomposition of structural material while slow and active SOM have high nutrient contents and release nutrients mineralize while they are being decomposed A complete description of the soil nutrient model is presented by Parton et al 1988 January 2001 CENTURY Tutorial apauigns 105 aue Joy moj 5 qa3H2v11 250 5 2 HZFOLINOS SINT pc papes OCH H2v11 uonennna Sunes 10 3 JINVOD HO CO HOS 2 3808 32v duris DE M uiti ASIN CALS 3 2 3 5 LAW WHOLITHLS ONNOH OAAO THH ONNOY WO 138 32v durs oge N ae IIE DATSE 2 x APMED Ryuajodoyauag QOM OH9MO HH DNIONY LS ISANGO 3 ang adua a 15 CENTURY Tutorial January 2001 m r2 y 05640 465aian I 097 x 15 7 effect of temperature on decomposition 1 un un 10 15 20 25 30 35 40 a Soil Temperature a ta a th T y 141 30 Jexp 8 5x effect of moisture on decomposition 0 0 0 2 04
63. ation and grazing on plant production and the seasonal patterns for live and dead biomass The model has been used to simulate the long term 30 60 year dynamics of soil organic matter and plant production for corn winter and spring wheat systems in Australia Carter et al 1993 Probert et al 1997 Canada Liang et al 1996 Sweden Paustian et al 1992 and sites in Oregon and Nebraska Metherell et al 1994 Parton and Rasmussen 1994 The model was used to correctly simulate the impact of adding different amounts and types of organic matter pea vine saw dust straw green manure and manure straw burning the use of different fertilizer levels different tillage practices stubble mulch conventional plow and no till and wheat pasture rotations on soil temperature soil water dynamics soil C and N levels plant production soil NOs leaching and soil N mineralization Paustian et al 1992 Probert et al 1997 The forest model has been evaluated for tropical temperate and boreal systems and used to simulate the response of forests to different natural disturbances and management practices Sanford et al 1991 Kelly et al 1998 Peng et al 1998 The CENTURY model has been used extensively to simulate the effect of environmental changes and management practices on natural and managed ecosystems at the site regional and global level The grassland model has been used to simulate the impact of climate change and increased atmospheric
64. centration from 350 ppm to 700 ppm CO2CCE 2 2 3 In a forest system the calculated effect on maximum C 5 ratios of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CPR 1 In a grassland crop system the calculated effect on production of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CPR 2 In a forest system the calculated effect on production of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CRS 1 In a grassland crop system the calculated effect on root shoot ratio of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CRS 2 In a forest system the calculated effect on root shoot ratio of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CTR 1 In a grassland crop system the calculated effect on transpiration rate of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CTR 2 In a forest system the calculated effect on transpiration rate of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm MT1C2 1 Accumulator for unlabeled surface CO2 loss due to microbial respiration during litter decomposition MT1C2 2 Accumulator for labeled surface CO2 loss due to microbial respiration during litter decomposition MT2C2 1 Accumulator for unlabeled soil CO2 loss due to respiration MT2C2 2 Accumulator for labeled soil CO2 loss due to respiration RESP 1 Annual unl
65. chedule file and store the results in a file named test bin you would enter the following at the command line century s c3grs n test The installation also includes two Windows Help files One is the complete text of the CENTURY User s Manual The other contains information about the CENTURY input parameters and output variables 19 CENTURY Tutorial January 2001 3 CENTURY Associated Files and Utility Programs The CENTURY environment Figure 3 1 consists of the CENTURY model and three utility programs FILE100 EVENT100 and LIST100 The FILE100 program assists the user in creating and updating any of the twelve data files used by CENTURY The EVENT100 program creates the scheduling file which contains the vegetation types and events that are to occur during the simulation The LIST100 program extracts selected output variables from the CENTURY binary output file and creates an ASCII listing of the variables values for the output intervals specified 1n the schedule file This listing can be viewed using any text editor or imported into a spreadsheet application for examination and graphing The CENTURY model obtains input values by reading up to twelve data files Each file contains a certain subset of variables for example the cult 100 file contains the values related to cultivation Within each file there may be multiple options in which the parameters are defined for multiple variations of the event For example within the cult 1
66. component of forest system g m2 WOOD2K 8 S in WOOD2 dead large wood component of forest system g m2 WOOD38K 8 S in WOODS dead coarse roots component of forest system g m2 WOODE 3 Sum of S in wood components of forest system g m2 Appendix 2 24 Appendix 2 CENTURY Output Variables by Category Water and Temperature Output Variables ADEFAC Average annual value of DEFAC the decomposition factor which combines the effects of temperature and moisture The effect of soil anaerobic conditions on decomposition used as a multiplier on all belowground decomposition flows ASMOSY 1 Soil water content of layer 1 cm ASMOS 2 Soil water content of layer 2 cm ASMOSY 3 Soil water content of layer 3 cm ASMOS 4 Soil water content of layer 4 cm ASMOSY 5 Soil water content of layer 5 cm 5 5 6 Soil water content of layer 6 cm ASMOS 7 Soil water content of layer 7 cm ASMOS 8 Soil water content of layer 8 cm ASMOS 9 Soil water content of layer 9 cm ASMOS 10 Soil water content of layer 10 cm ASMOS NLAYER 1 Soil water content in deep storage layer cm 2 Water available to grass crop tree for growth in soil profile sum of layers 1 through NLAYPG cm 20 AVH20O 2 Water available to grass crop tree for survival in soil profile sum of all layers in profile 1 through NLAYER cm 20 AVH20OX 3 Water in the first 2 so
67. d Options 8 1 Run LIST100 Using Command Line Parameters 8 2 Run CENTURY Using a DOS Batch File 8 8 Combining the Above Options Appendices Appendix 1 Literature on CENTURY model Appendix 2 CENTURY Output Variables By Category CO2 Output Variables Crop and Grass Output Variables Forest Output Variables Nitrogen Output Variables Phosphorus Output Variables Soil Output Variables Sulfur Output Variables Water and Temperature Output Variables Appendix 3 CENTURY Parameterization Workbook lt site gt 100 crop 100 tree 100 fix 100 Appendix 4 CENTURY Command Lines il 63 63 64 65 Appendix 1 1 Appendix 2 1 Appendix 2 1 Appendix 2 4 Appendix 2 6 Appendix 2 9 Appendix 2 14 Appendix 2 18 Appendix 2 22 Appendix 2 27 Appendix 3 1 Appendix 3 1 Appendix 3 12 Appendix 3 17 Appendix 3 26 Appendix 4 1 Figures Figure 1 1 Overall flow diagram for the CENTURY model 2 Figure 1 2 Flow diagram for the soil carbon submodel 4 Figure 1 3 Impact of soil temperature a and rainfall b on decomposition 5 Figure 1 4 Flow diagram for the nitrogen submodel 6 Figure 1 5 Flow diagram for the phosphorus submodel 7 Figure 1 6 Flow diagram for the water flow submodel 9 Figure 1 7 Flow diagram for the grassland crop submodel 11 Figure 1 8 Flow diagram for the tree growth submodel 12 Figure 1 9 General flow diagram for the DAYCENT model 15 Figure3 1 CENTURY model environment showing the relationship between programs and the fil
68. e and W K Lauenroth 1996 Soil organic matter and nutrient availability responses to reduced plant inputs in shortgrass steppe Ecology 77 2516 2527 Kelly R H W J Parton G J Crocker P R Grace J M lschens Poulton and D D Richter 1997 Simulating trends in soil organic carbon in long term experiments using the Century model Geoderma 81 75 90 Appendix 1 3 Appendix 1 Literature on CENTURY model Kelly R H W J Parton M D Hartman L K Stretch D S Ojima D S Schimel 2000 Intra and interannual variability of ecosystem processes in shortgrass steppe Journal of Geophysical Research Atmospheres 105 20 093 20 100 Kittel T G F D S Ojima D S Schimel McKeown J G Bromberg T H Painter Rosenbloom W J Parton and F Giorgi 1996 Model GIS integration and data set development to assess terrestrial ecosystem vulnerability to climate change Pages 293 297 in GIS and Environmental Modeling Progress and Research Issues Lauenroth W K D L Urban D P Coffin W J Parton H H Shugart T B Kirchner and T M Smith 1993 Modeling vegetation structure ecosystem process interactions across sites and ecosystems Ecological Modelling 67 49 80 656 Lyon D C A Monz R Brown and A K Metherell Soil organic matter changes over two decades of winter wheat fallow cropping in western Nebraska E A Paul and C V Cole editors Soil organic matter in temperate agricultural ecosystem
69. e Time variable listing from your lis file It will be the first column of data Click on the first Time value in the column of data Use your mouse to drag the thumb in the scroll bar to the right of the spreadsheet to the bottom of the page Press and hold the Shift key while clicking on the last value in the Time column Then click on the button to the right of the text box in the reduced Chart Wizard dialog box to restore the Chart Wizard dialog box to its original size Finally select the Y values for your graph Click on the button to the right of the Y Values text box Locate the column of output data for the variable name you selected as the Name for the series you are graphing Click on the first output value for the selected variable Use your mouse to drag the thumb in the scroll bar to the right of the spreadsheet to the bottom of the page Press and hold the Shift key while clicking on the last value in the selected variable s column of output data Then click on the button to the right of the text box in the reduced Chart Wizard dialog box to restore the Chart Wizard dialog box to its original size At this point you can click the Finish button to display the graph 52 CENTURY Tutorial January 2001 If you want to display more than one data series on the graph right click on the graph and select the Source Data option from the popup menu or select the Chart Source Data option from the main Excel menu Click on the Series
70. e by the type of tree removal selected TFST Marks the current month as the first month of growth for forest Addtl This command has no additional it is simply marked or unmarked Mark TFST Unmark TFST Output The year month and the word TFST TLST Marks the current month as the last month of growth for forest Addtl This command has no additional it is simply marked or unmarked Mark TLST Unmark TLST Output The year month and the word TLST 44 CENTURY Tutorial January 2001 5 2 6 Explanation of System Commands Each system command 15 described in the following format XXXX The command name and explanation What additional information the command needs Execute How the command should be entered FILL Copies the last event command and addtl if applicable to the number of months specified The number of months to fill into 1 11 Execute FILL number NEXT Changes to the next month If the current month is December changes to January of the next year If the current year is the last year changes to January of the first year Addtl None Execute NEXT NXTA NeXT Auto Toggle switch command that when on automatically does a NEXT command after each event command is entered The default 1s off NEXT command is not done automatically after each event command None Execute NXTA GOMTChanges to the given month in the current year The month number 1 12
71. e is calculated from the parameter radlp as a function of C E ratios of the surface active SOM pool You can either set it up as fixed values or let it float When using fixed values for radlp it is a prescribed value that is generally higher when leaf litter is of lower initial quality Typical fixed values for different systems are mm mme nmm 3 ol ee _ 2 s fo foie Sid Typical floating values for different systems are mmn 55 om pm a maso ___ 9 Appendix 3 27 Appendix 3 CENTURY Parameterization Workbook 3 PHOSPHORUS AND SULFUR If you are only modeling see nelem in your lt site gt 100 file then these parameters are irrelevant If you do want to model P and S then there are 2 ways to supply P inputs and 3 ways to supply S inputs and S can be supplied by weathering of parent material in which case you should appropriately adjust parent 2 and parent 3 in your Site 100 file and pparm 2 and pparm 3 in the fix 100 file parent i controls the amount of P or S in parent material and pparm i controls the weathering rate in units of the fraction of parent material weathered to mineral form per year and S can be supplied as fertilizer inputs in which case you should make an appropriate option in the fert 100 file Atmospheric S inputs are accounted
72. e roots and coarse roots for a forested system lignin content of vegetation aboveground and belowground for grasses split into leaves branches large wood fine roots and coarse roots for a forested system Work through the CENTURY Parameterization Workbook to help you create the parameterization for your site and crop and or tree The CENTURY Parameterization Workbook 15 a supplement to the CENTURY User s Manual The workbook is designed to lead you through the full parameterization of CENTURY for a particular site adjusting the appropriate parameters that control short term and long term behavior goal 1s to help you work through the maze of parameters and understand how they can be estimated from real world data Another tool that will help you set input parameter values for your CENTURY simulation is the Excel workbook century curves xls This spreadsheet contains interactive graphs for several of the CENTURY curves You can modify the input parameter values for a given curve for example the temperature growth curve and see how the parameter values you have selected effect the shape of the curve as computed by the CENTURY model 24 CENTURY Tutorial January 2001 Decide what types of events you want to simulate For example do you want to include fire in your simulation of the system Is the system tilled Is fertilizer added how many gN m 2 Do you want to simulate grazing What type of harvest is conducted How many cm of
73. e section of the dialog box You should see the text Scatter with data points connected by lines without markers as the description for the type of graph that will be created Press the Finish button to display the graph The following directions will lead you step by step through the process of creating an XY graph for one of your lis file output variables Select Insert Chart from the main menu or click on the Chart Wizard button 1n the Excel toolbar This will bring up the Chart Wizard In Step 1 of the Chart Wizard click on the Standard Types tab Select the XY Scatter option and click on the bottom right button in the Chart sub type section of the dialog box You should see the text Scatter with data points connected by lines without markers as the description for the type of graph that will be created Click the Next button to go to Step 2 Select the Series tab Click on the button to the right of the Name text box The button looks like small spreadsheet with red black and white cells After clicking on the button the Chart Wizard dialog box will be reduced in size Decide which variable you would like to graph and click on its name in the spreadsheet listing of your lis file Then click on the button to the right of the text box in the reduced Chart Wizard dialog box to restore the Chart Wizard dialog box to its original size To set the X values for your graph click on the button to the right of the X Values text box Locate th
74. e structure 19 Figure 7 1 Flow diagram for the grassland crop submodel 50 Figure 7 2 Flow diagram for the forest production submodel 51 Figure 7 8 Flow diagram for the water submodel The structure represents model set up to operate with NLAYER set to 5 52 Figure 7 4 The pools and flows of carbon the CENTURY model The diagram shows the major factors which control the flows 53 Figure 7 5 pools and flows of nitrogen in the CENTURY model The diagram shows the major factors which control the flows 54 Figure 7 6 pools and flows of phosphorus in the CENTURY model The diagram shows the major factors which control the flows 55 Figure 7 7 The pools and flows of sulphur in the CENTURY model The diagram shows the major factors which control the flows 56 iii 1 CENTURY Tutorial January 2001 1 CENTURY Model Overview 1 1 Introduction This document presents information about the monthly version of the CENTURY Model Version 4 0 We will also present an overview about the status on the DAYCENT model which simulates plant soil systems using a daily time step The DAYCENT model is capable of simulating detailed daily soil water and temperature dynamics and trace gas fluxes CH4 0 NOx and which are not simulated in CENTURY Version 4 0 The CENTURY model is a generalized plant soil ecosystem model that simulates plant production soil carbon dynamics soil nutrient dynamics and soil water and temperature The
75. en ratio L N of the litter more structural with higher L N ratios The CENTURY model assumes that decomposition of plant residues and the SOM pools 1s microbially mediated with an associated microbial respiration loss Microbial respiration losses from decomposition of active SOM increase with the soil sand content from 30 to 8096 as sand content increases to 9096 while microbial respiration losses are approximately 50 for decomposition of all of the other litter and SOM pools Each of the litter and soil SOM pools have pool specific maximum decomposition rates with the maximum rate being reduced by an abiotic soil decomposition factor that is controlled by the soil moisture and soil temperature Figure 1 3 The soil temperature function increases exponentially with increasing temperature while the soil moisture function increases as the ratio of stored water plus current rainfall to potential evapotranspiration increases the curve is most sensitive to changes in the ratio below 0 6 decomposition rate of structural litter is also a function of the fraction of the structural material that 1s lignin lower for higher fractions and the lignin fraction of plant material 15 assumed to flow directly to slow SOM as plant structural material decomposes The model also assumes that the fraction of the passive pool formed during the decomposition of active and slow SOM increases with clay content The net effect of the soil texture contro
76. er SOM dynamics for grassland agricultural forest and savanna systems Figure 1 1 The savanna system simulates the growth of trees and grasses crop growth can also be represented separately and includes competition for light nutrients and water The grass crop and forest systems have different plant production submodels that are linked to common soil organic and nutrient cycling submodels The model was developed with the bias that growth of cropland grassland and forest systems can be increased by adding soil nutrients The model structure reflects this bias with the soil nutrient cycling and soil organic matter dynamics being represented in great detail while plant growth is represented using relatively simple submodels The soil organic matter and nutrient submodels represent the flow of C P and S in plant litter and different organic and inorganic soil pools with mineralization of soil nutrients primarily resulting from turnover of soil organic matter pools The plant production model calculates plant production and allocation of nutrients to live aboveground and belowground compartments as a function of climatic factors and available soil nutrients CENTURY Tutorial January 2001 The model uses a monthly time step The major input variables include 1 monthly precipitation 2 monthly average maximum and minimum air temperature 3 soil texture 4 lignin N S and P content of plant material and 5 soil and atmospheric N inputs
77. et the allometric controls on LAI as follows maxlai maximum allowable LAI m m klai large wood mass g C m at which half of the maximum LAI is achieved g C m Source for LAI data 6 d SAPWOOD ALLOMETRIES Set the relationship between sapwood and total wood as sapk Maximum sapwood mass in mature stand can be approximately estimated as 10 years worth of wood production g C m Appendix 3 23 Appendix 3 CENTURY Parameterization Workbook Symbiotic biological N fixation is parameterized as snfxmx 2 maximum fixed per g C NPP This can be approximated as symbiotic N fixation annual NPP g C Remember to set this to the maximum value it will be reduced if nitrogen availability is high enough Enter the value used below snfxmx 2 fixed g C NPP Sources for N input data 7 LIGNIN FRACTION OF FOREST COMPONENTS The lignin content of tree components is system specific The following table shows ranges of values we have used tree component parameter lignin fraction leaves wdlig 1 0 14 0 18 fine roots wdlig 2 0 09 0 28 fine branches wdlig 3 0 20 0 35 large wood wdlig 4 0 20 0 35 coarse roots wdlig 5 0 20 0 35 8 DOUBLED CO PARAMETERS CENTURY allows simulations to be conducted assuming a doubling of atmospheric CO concentration from 350 ppm to 700 ppm The following parameters control the effects of doubled CO on NPP transpiration C E ratios and root shoot
78. for 9 years EVENT100 will warn you of this when you save your schedule file The model will run without any problem in this case with year 1 repeated 5 times and year 2 repeated 4 times The warning is to inform you of what 16 happening at the end of your repeating sequence 35 CENTURY Tutorial January 2001 This information will be helpful if you need to have the repeating sequence stop at the end of the repeating years rather than in the middle of the sequence Each block in the schedule file starts with a set of header lines showing the block number and an optional comment the last year of simulation for the block the number of years in the repeating sequence the output starting year the output month the output interval the weather choice for this block The events scheduled for this block follow next The last line of the block is the End of Block Marker 999 999 X The output starting year may be any year greater than or equal to the starting year The output month may be any month 1 through 12 The output interval indicates how many times the state variables are written to the output file A value of 1 writes the output annually 0 0833 1 12 writes monthly output As a smaller value results in a larger output file size the user may wish to specify different interval values for each block For example the simulation might run to equilibrium with grassland and check peak standing crop and SOM in September from 1800 to 1899 St
79. h stubble mulch management until 1980 followed by wheat sorghum fallow To model this series the model user would set up the following blocks in EVENT100 Block Years Management Repeating sequence 1 0 1919 Grass with grazing 1 year 2 1920 Cultivation to break the sod 1 year 3 1921 1950 Wheat fallow plow straw removal2 years 4 1951 1980 Wheat fallow stubble mulch 2 years 5 1981 1992 Wheat sorghum fallow 9 years This period needs to be long enough to establish equilibrium conditions To check for equilibrium look at the output variables for SOM If the values for these variables have leveled off then the system is said to be in equilibrium Block 3 in this example is 2 year repeating sequence of wheat fallow that begins in 1921 and ends in 1950 The length of the block is 30 years Since the length of the repeating sequence is 2 years the entire block will be completed 15 times within the 30 year period Year 1921 1s year 1 in the repeating sequence year 1922 1s year 2 in the repeating sequence year 1923 1s year 1 in the repeating sequence year 1924 1s year 2 in the repeating sequence an so on The two years of management events repeat to the end of the block with year 1949 being year 1 of the repeating sequence and year 1950 being year 2 of the repeating sequence If the number of years in the repeating sequence and the number of years in the block do not match up for example if you have a two year repeating sequence that runs
80. he addition phase If no option 1s responded to with a yes answer the program will return to the previous menu of five actions Once an affirmative response has been given the user will be asked for a new abbreviation and description Enter a new abbreviation The abbreviation must be unique to that file and no more than 5 characters if a duplicate is entered the user will be asked to enter another abbreviation Enter a new description The description may not be longer than 65 characters 28 CENTURY Tutorial January 2001 Then for each value in that option the program will display the value which the original option had for that parameter and ask the user for a new value Commands L new value return Name PRDX 1 Previous value 300 Enter response The user may enter any of these possible responses as shown on the Command line see the definition of that enter D find a specific parameter in that option sese enter F See help message mene rnt ee nene enter H list the next 12 Parameters o osos ooo ave vU ids eta s oig et otia enter L quit retaining the old values for this and the remaining parameters a e enter Q take the 1 enter return entera new value 2 enter a new value The command and previous value lines will
81. hoots during grazing fire g m2 SHRMAI 2 Annual accumulator of labeled C removed from shoots during grazing fire g m2 STDCIS 1 Unlabeled C in standing dead g m2 STDCIS 2 Labeled C in standing dead g m2 STDEDC C in standing dead material g m2 Appendix 2 5 Appendix 2 CENTURY Output Variables by Category Forest Output Variables ACRCIS 1 Growing season accumulator for unlabeled C production in forest system coarse root component g m2 y ACRCIS 2 Growing season accumulator for labeled C production in forest system coarse root component g m2 y AFBCIS 1 Growing season accumulator for unlabeled C production in forest system fine branch component g m2 y AFBCIS 2 Growing season accumulator for labeled C production in forest system fine branch component g m2 y AFRCIS 1 Growing season accumulator for unlabeled C production in forest system fine root component g m2 y AFRCIS 2 Growing season accumulator for labeled C production in forest system fine root component g m2 y ALVCIS 1 Growing season accumulator for unlabeled C production in forest system leaf component g m2 y ALVCIS 2 Growing season accumulator for labeled C production in forest system leaf component g m2 y ALWCIS 1 Growing season accumulator for unlabeled C production in forest system large wood component g m2 y ALWCIS 2 Growing season accumulator for labeled C production in forest system
82. ial C E ratio to cerfor 3 Note that the maximum C E ratio will never actually be achieved in practice so it must be set higher than the observed highest value Record the values for cerfor below C N c s VARIABLE i 1 i 2 1 3 cerfor 1 1 i cerfor 2 1 i cerfor 3 1 i cerfor 1 2 i cerfor 2 2 i cerfor 3 2 i cerfor 1 3 i cerfor 2 3 i cerfor 3 3 i cerfor 1 4 i cerfor 2 4 i cerfor 3 4 i cerfor 1 5 i cerfor 2 5 i cerfor 3 5 i Set values for forrtf as in option 2 above 4 WOOD DECOMPOSITION RATES No good general scheme exists for estimating wood decomposition rates from chemical or physical properties of the wood therefore CENTURY sets wood decomposition as a system specific parameter To set this first estimate the mean turnover times of each wood pool then calculate the values for decw Mean turnover times can be estimated as the half life in terms of mass loss of an average piece of woody debris or assuming steady state questionable for large wood as standing stock input rate Again for belowground woody debris there is often very little data a value similar to that for large wood can be used in the absence of other information Appendix 3 20 Appendix 3 CENTURY Parameterization Workbook Calculate values for decw Perform a 3 year simulation using default parameters and mean weather for your system Output and calculate average values of defac and anerb for the third year
83. il layers cm 20 DEFAC Decomposition factor based on temperature and moisture EVAP Monthly evaporation cm IRRACT Actual amount of irrigation cm h20 month IRRTOT Accumulator for irrigation cm h2o PET Monthly potential evapotranspiration cm Appendix 2 25 Appendix 2 CENTURY Output Variables by Category PETANN Annual potential evapotranspiration cm PRCANN Annual precipitation cm PRCFAL Fallow period precipitation the amount of rain which falls during the months after harvest until the month before the next planting cm PTTR Potential transpiration water loss for the month RAIN Monthly precipitation cm RWCF 1 Relative water content for layer 1 RWCF 2 Relative water content for layer 2 RWCF 3 Relative water content for layer 3 RWCEF 4 Relative water content for layer 4 RWCF 5 Relative water content for layer 5 RWCF 6 Relative water content for layer 6 RWCF Relative water content for layer 7 RWCF 8 Relative water content for layer 8 RWCF 9 Relative water content for layer 9 RWCF 10 Relative water content for layer 10 SNLQ Liquid water in snowpack cm SNOW Snowpack water content cm H20 STEMP Average soil temperature in deg C STREAM 1 H20 of stream flow base flow storm flow TAVE Average air temperature deg C TRAN Monthly transpiration cm Appendix 2 26 Appendix 3 CENTURY Parameterization Wor
84. imum rates decreased if soil nutrients supply is insufficient the most limiting nutrient controls production The grassland crop model also includes the effect of shading from dead vegetation while the forest model includes the effect of live leaf area on plant production Potential production 1s a function of the maximum growth rate for each grassland crop or forest system and 1s reduced by 0 1 scalars depending on the factors that limit production Plant nutrient uptake is a function of live root biomass with uptake increasing as live root biomass increases up to 300 grams per square meter As mentioned earlier most forest and grassland crop systems will increase plant production with addition of nutrients The forest and grassland crop models are generic plant growth models that can be parameterized to represent a large variety of crop grassland and forest systems by altering crop and forest specific parameters grassland crop model includes live shoots and roots and standing dead plant parts while the forest system includes live shoots fine roots large wood fine branches and coarse roots The effect of grazing and fire on the grassland crop system 1s represented in the model with the major effect of fire being the increase in root to shoot ratio increase in the C N ratio of roots and shoots removal of vegetation and return of nutrients from the fire Ojima et al 1900 Grazing removes live and dead vegetation alters the root to shoo
85. inal version of the file that was being edited If necessary the user can copy this backup file into a file of the original file name 34 CENTURY Tutorial January 2001 5 2 EVENT100 EVENT100 is the scheduling preprocessor for the CENTURY Soil Organic Matter Model This preprocessor allows the user to schedule management events and crop growth controls at specific times during the simulation and produces an ASCII output file which 1s read in by CENTURY EVENT100 uses a grid like display to allow the user to move among months and years to schedule crop type tree type planting and harvest months first and last month of growth for grassland or perennial crops senescence month cultivation fertilizer addition irrigation addition of organic matter straw or manure grazing fire tree removal and erosion 5 2 1 The Concept of Blocks EVENT100 produces a scheduling file which drives events in CENTURY It also produces the general time information about the simulation such as the starting time and ending time The scheduling of crop rotations and management events uses the principle of repeating sequences within blocks of time block is a series of events which will repeat themselves in sequence until the ending time of the block is reached For example a series of historical farm practices might have been breaking of the native sod in 1920 a wheat fallow rotation with plow cultivation and straw removal until 1950 wheat fallow wit
86. ins and L L Wallace editors Fire in North American tallgrass prairies University of Oklahoma Press Norman Oklahoma USA 601 Appendix 1 4 Appendix 1 Literature on CENTURY model D S W J Parton D S Schimel T G F Kittel and J M O Scurlock 1993 Modeling the effects of climatic and CO2 changes on grassland storage of soil C Water Air and Soil Pollution 70 643 657 664 Ojima D S B O M Dirks E P Glenn Owensby and J M O Scurlock 1993 Assessment of C budget for grasslands and drylands of the world Water Air and Soil Pollution 70 95 109 663 Ojima D S D S Schimel W J Parton and C E Owensby 1994 Long and short term effects of fire on nitrogen cycling in tallgrass prairie Biogeochemistry 24 67 84 687 Ojima D S W J Parton Coughenour J M O Scurlock Kirchner T G F Kittel D O Hall D S Schimel E Garcia Moya T G Gilmanov T R Seastedt Apinan Kamnalrut J I Kinyamario S P Long J C Menaut O E Sala R J Scholes and J A van Veen 1996 Impact of climate and atmospheric carbon dioxide changes on grasslands of the world Pages 271 311 in Breymeyer D O Hall J M Melillo and G I en editors Global change effects on coniferous forests and grasslands SCOPE volume 56 John Wiley amp Sons Chichester West Sussex England 790 Ojima D S W J Parton D S Schimel and Owensby Simulating the long term impact of burning on C N and P cycling in
87. ion of no more than 5 characters 30 CENTURY Tutorial January 2001 Enter a new description or a return to use the existing description The description may not be longer than 65 characters The next menu will show the subheadings within the file Which subheading do you want to work with 0 Return to main menu 1 Climate parameters 2 Site and control parameters 8 External nutrient input parameters 4 Organic matter initial parameters 5 Forest organic matter initial parameters 6 Mineral initial parameters 7 Water initial parameters Enter selection Entering a response of 1 through 7 will cause the first parameter shown to be from that subheading The program then continues as with the regular Change function For each value in that subheading the program will display the value which the original had for that parameter and ask the user for a new value Commands L new value return Name PRDX 1 Previous value 300 Enter response The user may enter any of these possible responses as shown on the Command line see the definition of that parameter enter D find a specific parameter that 200 222 enter F see a help message enter H list the next 12 parameters 000000 0011 enter L quit retaining the old values for this and the remaining parameters i UBISOODUONT enter Q take the old value entera new v
88. ized from the WOOD3 dead coarse root component of a forest system g m2 WDFX Annual atmospheric and non symbiotic soil N fixation based on annual precipitation wet and dry deposition g m2 WDFXA Annual fixation in atmosphere wet and dry deposition g m2 WDFXAA Annual accumulator for atmospheric N inputs g m2 y WDFXAS Annual accumulator for soil N fixation inputs g m2 y WDFXMA Monthly N fixation atmosphere g m2 WDFXMS Monthly non symbiotic soil N fixation g m2 WDFXS Annual non symbiotic soil fixation based on precipitation rather than soil N P ratio g m2 WOODIE 1 N in WOOD1 dead fine branch component of forest system g m2 WOOD2K 1 N in dead large wood component of forest system g m2 WOODSE 1 N in WOOD3 dead coarse roots component of forest system g m2 WOODE 1 Sum of N in dead components of forest system g m2 Appendix 2 13 Appendix 2 CENTURY Output Variables by Category Phosphorus Output Variables AGLIVE 2 P in aboveground live for grass crop g m2 AMINRL 2 Mineral P in layer 1 before uptake by plants BGLIVE 2 P in belowground live for grass crop g m2 CROOTE 2 P in forest system coarse root component g m2 CRPSTG 2 Retranslocation P storage pool for grass crop g m2 EGRACC 2 Accumulator of P in grain tuber production for grass crop g m2 EGRAIN 2 Economic yield of P in grain tubers for grass crop g m2
89. kbook CENTURY Parameterization Workbook lt site gt 100 file Most of the parameters in the lt site gt 100 file will have to be adjusted to account for the unique properties of your particular system However some sets of parameters are more important than others For example climate and soil physical are very important but the initial organic matter and water parameters are not important if you include an equilibrium block in your schedule file See Appendix 2 12 in the Century User s Manual for definitions of the parameters in this file SITE INFORMATION CENTURY PARAMERERIZATION Site Name Latitude Longitude Elevation System simulated Modeler Date 1 PHYSICAL ENVIRONMENT 1 CLMATE PARAMETERS Enter below the mean climate for the site These are averages for each calendar month of daily maximum and minimum air temperatures and monthly total precipitation Standard deviation and skewness of monthly precipitation totals are needed only if the stochastic precipitation option is to be used and can be generated by using the FILE100 utility Appendix 3 1 Appendix 3 CENTURY Parameterization Workbook TEMPERATURES PRECIPITATION cm MONTH MINIMUM MAXIMUM MEAN S D SKEWNESS Source for climate data 1 b SITE AND CONTROL PARAMTERS ivauto controls how SOM pools are initialized ivauto 0 the initial SOM values in your lt site g
90. king H K Gunnewick D S Jenkinson L S Jensen R H Kelly A S Komarov C Li J A E Molina T Mueller W J Parton J H M Thornley and A P Whitmore comparison of the performance of nine soil organic matter models using datasets from seven long term experiments Geoderma 81 153 225 Togtohyn C D S J Luvsandorjiin J Dodd and S Williams 1996 Simulation studies of grazing in the Mongolian Steppe Pages 561 562 in Rangelands in a sustainable biosphere Proceedings of the Fifth International Rangeland Congress Salt Lake City Utah USA Vallis I W J Parton B A Keating and A W Wood 1996 Simulation of the effects of trash and N fertilizer management on soil organic matter levels and yields of sugarcane Soil amp Tillage Research 38 115 132 VEMAP et al J M Melillo J Borchers J Chaney Fisher S Fox A Haxeltine A Janetos D W Kicklighter T G F Kittel A D McGuire R McKeown R Neilson R Nemani D S T Painter Y Pan W J Parton L Pierce L Pitelka C Prentice B Rizzo Rosenbloom S Running D S Schimel S Sitch T Smith and I Woodward 1995 Vegetation ecosystem modeling and analysis project comparing biogeography and biogeochemistry models in a continental scale study of terrestrial ecosystem responses to climate change and CO2 doubling Global Biogeochemical Cycles 9 407 437 743 Vitousek P M Turner W J Parton and R L Sanford 1994 Litte
91. l run depends on the option abbreviation used in the schedule file The files fix 100 and lt site gt 100 have only one option in the file crop 100 crop parameterizations for one to many crops cult 100 cultivation parameterizations for one to many cultivation options fert 100 fertilization parameterizations for one to many fertilization options fire 100 fire parameterizations for one to many fire options fix 100 fixed parameters for the most part these will not be changed graz 100 grazing parameterizations for one to many grazing options harv 100 harvest parameterizations for one to many harvest options irri 100 irrigation parameterizations for one to many irrigation options omad 100 organic matter addition parameterizations for one to many organic matter addition options tree 100 tree parameterizations for one to many trees trem 100 tree removal parameterizations for one to many trees lt site gt 100 site specific parameters sch schedule file for the simulation wth optional a historical weather data file for your site Other files which should be in your CENTURY directory are CENTURY utilities EVENT 100 FILE100 LIST100 used to create and or modify schedule files used to modify parameter files used to extract output from the binary output file created by CENTURY to an ASCII text file The parameter definition files crop def cult def fert def fire def fix def graz def harv def irri def omad def tree def trem def
92. large wood component g m2 Appendix 2 21 Appendix 2 CENTURY Output Variables by Category EUPPRT 5 3 Growing season accumulator for S uptake by forest coarse root component g m2 FBRCHE 8 S in forest system fine branch component g m2 FERTOT 3 Accumulator for S fertilizer FORSTG 8 Retranslocation S storage pool for forest 3 S in forest system fine root component g m2 FRSTE 3 Sum of S in forest system live components RLEAVE 3 FROOTE 3 FBRCHE 3 RLWODE 3 CROOTE 3 g m2 FSYSE 8 Total S in forest system 1 e sum of soil organic matter trees dead wood forest litter 3 Gross mineralization of S LHZEAC 3 Accumulator for S inputs to 0 20 cm layer from the lower horizon pools associated with soil erosion g m2 1 3 Metabolic S in surface litter g m2 2 8 Metabolic S in soil litter g m2 METMNR 1 3 Net mineralization for S for surface metabolic litter METMNR 2 3 Net mineralization for S for soil metabolic litter MINERL 1 3 Mineral S content for layer 1 g m2 MINERL 2 3 Mineral S content for layer 2 g m2 MINERL 3 3 Mineral S content for layer 3 g m2 4 3 Mineral S content for layer 4 g m2 MINERL 5 3 Mineral S content for layer 5 g m2 6 3 Mineral S content for layer 6 g m2 7 3 Mineral S content for layer 7 g m2 MINERL 8 3 Mineral S c
93. lig 0 0 Appendix 3 11 Appendix 3 CENTURY Parameterization Workbook crop 100 file The crop 100 file is used to represent cropped and grassland systems The CENTURY installation package contains a crop 100 file for many common crops corn wheat etc and grasses C3 C4 etc that have been used in the past Most of the grasses were parameterized with data from LTER sites while many of the crop parameterizations use data from VEMAP sites We suggest that you use one of these existing parameterizations as a starting point and use the following suggestions to modify the parameters as needed to represent the vegetation in your particular system Do not hesitate to change the recommended values of parameters to better represent your vegetation especially if you have data See Appendix 2 1 in the Century User s Manual for definitions of the parameters in this file 1 MAXIMUM PRODUCTION Maximum production is rarely directly observed in either the model or reality and must be inferred Maximum net production is expressed as the theoretical maximum net biomass production per month in terms of total mass not C Values of 200 300 for grasses and slow growing crops e g winter wheat and up to 600 biomass for fast growing crops corn have been used prdx 1 2 TEMPERATURE RESPONSES The effect of temperature on production is controlled by the parameter ppdf Typical values for vegetation types are listed below Fo
94. lmala and S Phongpan 2000 General model for N2O and N2 gas emissions from soils due to denitrification Global Biogeochemical Cycles 14 1045 1060 Del Grosso S J W J Parton A R Mosier D S Ojima and M D Hartman 2000 Interaction of soil carbon sequestration and N20 flux with different land use practices Pages 303 311 in J van Ham et al editors Non CO2 greenhouse gases scientific understanding control and implementation Kluwer Academic Publishers Amsterdam Netherlands 941 Del Grosso S J W J Parton Mosier M D Hartman J Brenner D S Ojima and D S Schimel 2001 Simulated interaction of carbon dynamics and nitrogen trace gas fluxes using the DAYCENT model Pages 303 332 in M Schaffer et al editors Modeling carbon and nitrogen dynamics for soil management Press Boca Raton Florida USA Del Grosso S J W J Parton Mosier M D Hartman Keough G A Peterson D S Ojima and D S Schimel 2001 Simulated effects of land use soil texture and precipitation on N gas emissions using DAYCENT Pages in R F Follett J L Hatfield editors Nitrogen in the environment sources problems and management Elsevier Science Publishers The Netherlands press Del Grosso S J D S Ojima W J Parton Mosier G A Peterson and D S Schimel Effects of dryland cropping intensification on SOM and greenhouse gas exchanges using the DAYCENT ecosystem model Environmental Pollution s
95. ls on decomposition of active and slow SOM is to increase soil carbon stabilization for soils with low sand content and high clay content A through description of the CENTURY SOM model and justification for the approach used in the model are presented by Parton et al 1994 The CENTURY model has N Figure 1 4 and P Figure 1 5 pools that are analogous to all of the soil carbon pools The amount of N and P flowing out of a particular pools is equal to the product of the carbon flow out of the pool and the carbon to the element ratio of the pool A similar approach is used to calculate the flow of different elements into a specific pool but the carbon to element ratio of the receiving pool is a function of the labile inorganic mineral nutrient concentration Low levels of available nutrients result in high C to element ratios for the different pools Each pool has an allowable carbon to element ratio The C N ratios of the SOM pools are narrow 5 20 compared to the C P ratios 100 to 400 Mineralization release of nutrients from SOM or immobilization of N and P uptake of nutrients by SOM occurs as a result of decomposition of dead plant material and the SOM CENTURY Tutorial January 2001 fractions Immobilization of nutrients into SOM generally occurs during the decomposition of structural plant material high C element ratio material while mineralization of nutrients occurs as a result of decomposition of active and slow SOM low C element r
96. m 350 ppm to 700 ppm CO2CCE 1 1 3 In a grassland crop system the calculated effect on minimum C S ratios of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CCE 1 2 1 In a grassland crop system the calculated effect on maximum C N ratios of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CCE 1 2 2 In a grassland crop system the calculated effect on maximum C P ratios of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CCE 1 2 3 In a grassland crop system the calculated effect on maximum C S ratios of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm Appendix 2 1 Appendix 2 CENTURY Output Variables by Category CO2CCE 2 1 1 In a forest system the calculated effect on minimum C N ratios of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CCE 2 1 2 In a forest system the calculated effect on minimum C P ratios of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CCE 2 1 3 In a forest system the calculated effect on minimum C S ratios of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CCE 2 2 1 In a forest system the calculated effect on maximum ratios of doubling the atmospheric CO2 concentration from 350 ppm to 700 ppm CO2CCE 2 2 2 In a forest system the calculated effect on maximum C P ratios of doubling the atmospheric CO2 con
97. model has been used to simulate ecosystem dynamics for all of the major ecosystems in the world and has been used for the dominant cropland and agroecosystems The model results have been compared to observed plant production soil carbon and soil nutrient data for the most common global natural and managed ecosystems The model has been used to simulate the response of these ecosystems to changes in environmental driving variables i e maximum and minimum air temperature precipitation and atmospheric levels and changes in the management practices grazing intensity forest clearing practices burning frequency fertilizer rates crop cultivation practices etc for grasslands crop forest and savanna ecosystems Appendix 1 includes the list of papers in which the CENTURY model has been used to simulate ecosystem dynamics for different ecosystems We have provided copies of four of the papers that describe the theoretical basis for the CENTURY model and examples where the model was used to simulate the ecosystem dynamics and compared with observed field data This document will describe 1 the theoretical basis and overall structure of the model 2 the procedures used to set up and run the model for a specific site and 3 the process used to adjust model parameters for best fit representation of site specific ecosystem dynamics 1 2 CENTURY Model Description The CENTURY model represents plant growth nutrient cycling and soil organic matt
98. mulation for this block The entered value must be greater than or equal to the starting year For example to run an eight year simulation from January 1920 to December 1927 inclusive the ending year will be 1927 next block will begin in January 1928 Enter the number of years in the repeating sequence Enter the number of years that will be set up in the block Enter the year to begin output Default the block starting year Enter a year greater than or equal to the starting year of the block or a return to accept the default Enter the month to begin output 1 12 Default 1 Enter a month between 1 and 12 or a return to accept the default Enter the output interval Monthly 0 0833 6 monthly 0 5 Yearly 1 0 Etc Default 0 0888 monthly Enter a time increment or a return to accept the default 39 CENTURY Tutorial January 2001 Enter the weather choice M mean values from the lt site gt 100 file S from the lt site gt 100 file but stochastic precipitation F from the beginning of an actual weather file C continued from an actual weather file without rewinding Default S Stochastic The possible answers are M to use the mean precipitation and temperature values which were read in from the site specific lt site gt 100 file S to use the stochastically generated precipitation and the mean temperature values from the site specific lt site gt 100 file If the precipita
99. n The README file can be viewed using Windows Notepad and contains additional information about the installation file executable files that will be installed are CENTURY EXE CENTURY executable EVENT100 EXE Event scheduler for CENTURY FILE100 EXE Parameterization utility LIST100 EXE Used to create ASCII output file This version of CENTURY runs from a DOS window in Windows 9x and Windows NT The 100 files are CENTURY parameter files The def files are definitions that go with the 100 files are will be used when you run FILE100 The sch files are sample schedule files Running CENTURY and its Utility Programs The PC version of CENTURY and its utility programs must be run from a DOS box in Windows 9x or Windows NT To open a DOS box select Start Programs MS DOS Prompt from the Windows Start menu Use the command to change to the directory where you CENTURY files are located For example when you open the DOS box you will most likely be in the Windows directory and the DOS prompt will show C NWINDOWS to change to the root directory enter the following command at the DOS prompt cd You should now be in the root directory In most cases the DOS prompt should now read C If you used the default CENTURY installation the CENTURY files will be in the C Ncentury directory To get to the CENTURY directory enter this command at the DOS prompt cd century If the command has executed successfully the DOS prompt will show C
100. n running CENTURY 1 Create the desired parameterizations in the 100 files using FILE100 2 Use 00 to create the schedule file for your simulation 3 Run the CENTURY simulation 4 Use LIST100 to extract the desired output from the binary output file produced by your CENTURY run 26 CENTURY Tutorial January 2001 5 1 FILE100 The FILE100 program 1s designed to help the user create new options or change values in existing options in any of the 100 data files used with EVENT100 and CENTURY This utility also provides parameter definitions units and valid values or ranges run FILE100 enter file100 and follow the on screen menus The program begins with a numbered list of the 100 files and asks the user to enter the number of the file s he wishes to work with File Updating Utility Enter the number of the file you wish to update 0 quit crop 100 cult 100 fert 100 fire 100 fix 100 graz 100 harv 100 irri 100 omad 100 10 tree 100 11 trem 100 12 lt site gt 100 13 weather statistics Enter selection A Within that 100 file the user may take any of five actions as shown by the next menu What action would you like to take 0 Return to main menu 1 Review all options 2 Add a new option 3 Change an option 4 Delete an option 5 Compare options Enter selection 27 CENTURY Tutorial January 2001 Reviewing a file will li
101. n the U S central grasslands region Pages 99 108 in M Clarholm and L BergstrL editors Ecology of arable lands Kluwer Academic Publishers Amsterdam Netherlands 546 Parton W J B McKeown V Kirchner and D S Ojima 1992 CENTURY Users Manual Colorado State University NREL Publication Fort Collins Colorado USA Parton W J D S Ojima D S Schimel and T G F Kittel 1992 Development of simplified ecosystem models for applications in Earth system studies the CENTURY experience Pages 281 302 in D S Ojima editor Earth system modeling Proceedings from the 1990 Global Change Institute on Earth System Modeling Snowmass Colorado USA 689 Parton W J J M O Scurlock D S Gilmanov R J Scholes D S Schimel T Kirchner J C Menaut T Seastedt E Garcia Moya Apinan Kamnalrut and J L Kinyamario 1998 Observations and modeling of biomass and soll organic matter dynamics for the grassland biome worldwide Global Biogeochemical Cycles 7 785 809 672 Parton W J and P E Rasmussen 1994 Long term effects of crop management in wheat fallow II CENTURY model simulations Soil Science Society of America Journal 58 530 536 694 Parton W J D S Schimel and D S Ojima 1994 Environmental change in grasslands assessment using models Climatic Change 28 111 141 696 Parton W J D S Schimel D S Ojima and C V Cole 1994 A general model for soil organic matter dynamics sensitivity to lit
102. n which there are unpaired plantings and harvests or first and last months of growth the user may continue on although the condition is detected If an error condition 1s detected in one of these cases the user is asked if the program should still terminate The user may return to the grid to correct the problems or continue on Next the user 15 asked for the name of an output file If a previous SAVE command has been executed that file name will be displayed as a default the user may use that name or supply a new name Also the user may quit without saving to any file by simply hitting the return key If an output file 1s produced it will be of the name lt file gt sch where file is the name supplied by the user Finally the EVENT100 program ends EVENT100 will ask for an output file name Execute QUIT 5 2 7 The i Option Reading from a Previous Schedule File EVENT100 includes the option of reading from a previously generated schedule file through the i option The schedule file must exist in the current directory and be of the name lt file gt sch Start EVENT100 by entering event100 1 file at the DOS prompt Note that the sch extension is not included For example to modify a schedule file named c3grs sch enter the following command line event100 1 c3grs EVENT100 will then read in the schedule file named The starting questions concerning site file name type of labeling year to begin labeling microco
103. nd SOM2 ST1C2 2 Accumulator for labeled CO2 loss due to microbial respiration during litter decomposition of surface structural into SOM1 and SOM2 ST2C2 1 Accumulator for unlabeled CO2 loss due to microbial respiration during litter decomposition of soil structural into SOM1 and SOM2 ST2C2 2 Accumulator for labeled CO2 loss due to microbial respiration during litter decomposition of soil structural into SOM1 and SOM2 Appendix 2 3 Appendix 2 CENTURY Output Variables by Category Crop and Grass Output Variables ACCRST Accumulator of C in straw removed g m2 AGCACC Growing season accumulator for aboveground C production g m2 y AGCISA 1 Growing season accumulator for aboveground unlabeled C production g m2 AGCISA 2 Growing season accumulator for aboveground labeled C production g m2 AGLCIS 1 Aboveground unlabeled C g m2 AGLCIS 2 Aboveground labeled C g m2 AGLCN Aboveground live C N ratio 999 if either component 0 AGLIVC C in aboveground live g m2 BGCACC Growing season accumulator for belowground C production g m2 BGCISA 1 Growing season accumulator for belowground unlabeled C production g m2 BGCISA 2 Growing season accumulator for belowground labeled C production g m2 BGLCIS 1 Belowground live unlabeled C g m2 BGLCIS 2 Belowground live labeled C g m2 BGLCN Belowground live C N ratio 999 if either component 0 BGLIVC C in belowground live
104. ndix 3 CENTURY Parameterization Workbook Nutrient pools P and S calculations are necessary only if nelem 2 or 3 Calculate each as biomass concentration N P S FRACTION VARIABLE i 1 i 2 i 3 3 c INITIAL WOODY DEBRIS AND ROOT LITTER POOLS This parameterization is only necessary for forest systems Enter the woody debris and belowground litter pools below Small woody debris is the wood litter typically measured in forest floor sampling Large woody debris is highly clumped spatially hence measures of its mass usually only come from deliberate efforts to quantify it specifically Data for belowground woody debris are rarely available a rough estimate can be made by assuming the ratio of belowground aboveground large woody debris is equal to the ratio of coarse root large wood live biomass the absence of any woody debris estimates these values can be crudely estimated as anywhere from 10 30 of their corresponding live pools Belowground litter is approximately the mass of dead fine roots in the absence of data it can be estimated as of the same order of magnitude as live fine roots If there is no data from which to initialize these pools they may be set to zero and will gradually equilibrate during the model run Calculate the initial pools Initial woody debris and root litter pools Pool Mass g m Variable Expression VALUE g m ED _ Tee Emu peso Pien Coarse root wd3cis 1 dead coarse debris root
105. nter depth of summer thaw Soil thickness cm Convert rooting zone depth and soil thickness to numbers of soil layers using the tables below Circle the corresponding values for nlaypg layers available for plant growth and nlayer total layers in solum Rooting zone Total DEPTH nlaypg nlayer 0 22 cm 1 1 23 37 cm 2 2 38 52 cm 3 3 53 74 cm 4 4 75 104 cm 5 5 105 134 cm 6 6 135 164 cm 7 7 165 194 cm 8 8 195 cm or more 9 9 Sources for soils data Appendix 3 3 Appendix 3 CENTURY Parameterization Workbook 1 4 STREAM FLOW CALBRATION If you want you can calibrate stream flow stream 1 by adjusting the parameters stormf and basef These parameters control monthly distribution of streamflow but they have no effect on water balance decomposition or production stormf is the fraction of excess water that runs off immediately in the current month the remainder goes to the baseflow storage pool in asmos nlayer 1 basef gives the fraction of this storage pool that runs off each month These parameters can be calibrated iteratively by comparing an observed time sequence of streamflow to the model predictions Note that to do this you must drive the model with the actual climate for the period not simply with the mean climate l e FIELD CAPACITY AND WILTING POINT Soil water contents at field capacity FC and wilting point WP for each soil layer can be set by the user or can be calculated based on different equations
106. ny Parton W J 1996 The CENTURY model Pages 283 298 in D S Powlson P Smith and J U Smith editors Evaluation of soil organic matter models using existing long term datasets NATO ASI Series Vol 138 Springer Verlag Berlin Germany 759 Parton W J Coughenour J M O Scurlock D S Ojima Gilmanov R J Scholes D S Schimel T Kirchner J C Menaut T R Seastedt E Garcia Moya A Kamnalrut J I Kinyamario and D O Hall 1996 Global grassland ecosystem modelling development and test of ecosystem models for grassland systems Pages 229 266 in A I Breymeyer D O Hall J M Melillo and G I editors Global change effects on coniferous forests and grasslands SCOPE volume 56 John Wiley amp Sons Chichester West Sussex England 789 Parton W J M Hartman D Ojima and D Schimel 1998 DAYCENT and its land surface submodel description and testing Global and Planetary Change 19 35 48 883 Parton W J E A Holland S J Del Grosso M D Hartman R E Martin A R Mosier D S Ojima and D S Schimel Generalized model NOX and 20 emissions from soils Journal of Geophysical Research Atmospheres in press Patwardhan A S R V Chinnaswamy A S Donigian Jr A K Metherell R L Blevins W W Frye and K Paustian 1995 Application of the CENTURY soil organic matter model to a field site in Lexington Kentucky Pages 385 394 in R Lal J Kimball E Levine and B A Stewart edit
107. ontent for layer 8 g m2 9 3 Mineral S content for layer 9 g m2 Appendix 2 22 Appendix 2 CENTURY Output Variables by Category MINERL 10 3 Mineral S content for layer 10 g m2 MINERL NLAYER 1 3 Deep storage layer for S leached PARENT 8 Parent material S g m2 RLEAVE 8 S in forest system leaf component g m2 RLWODE 8 S in forest system large wood component g m2 SIMNR 1 3 Net mineralization for S for surface microbes SOMI1E 1 3 SIMNR 2 3 Net mineralization for S for active pool SOM1E 2 3 S2MNR 3 Net mineralization for S for slow pool SOM2E 3 SS3MNR 3 Net mineralization S for passive pool SOM3E 3 SATMAC Accumulator for atmospheric S deposition g m2 SDRMAE 8 Annual accumulator of S removed from standing dead during grazing fire for grass crop g m2 SECNDY 3 Secondary S g m2 SHRMAE 3 Annual accumulator of S removed from shoots during grazing fire for grass crop g m2 SIRRAC Accumulator for irrigation S inputs g S m2 SOILNM 3 Annual accumulator for net mineralization of S in soil compartments soil organic matter belowground litter dead coarse roots g m2 1 3 S in surface microbe pool g m2 SOMIE 2 3 S in active soil organic matter g m2 SOM2EX 3 S in slow pool soil organic matter g m2 3 S in passive soil organic matter g m2 SOMSE 3 Sum of S in SOM1E SOM2
108. ors Advances in soil science soils and global change Press Inc Boca Raton Florida USA Paustian K O Andr M Clarholm A C Hansson Johansson J Lagerll T Lindberg R Pettersson and B Sohlenius 1990 Carbon and nitrogen budgets of four agro ecosystems with annual and perennial crops with and without N fertilization Journal of Applied Ecology 27 60 84 Paustian K W J Parton and J Persson 1992 Modeling soil organic matter in organic amended and nitrogen fertilized long term plots Soil Science Society of America Journal 56 476 488 642 Paustian E T Elliott G A Peterson and Killian 1996 Modelling climate and management impacts on soil carbon in semi arid agroecosystems Plant and Soil 187 351 365 Peng C M J Apps D T Price I A Nalder and D H Halliwell 1998 Simulating carbon dynamics along the Boreal Forest Transect Case Study BFTCS in central Canada 1 model testing Global Biogeochemical Cycles 12 381 392 Appendix 1 7 Appendix 1 Literature on CENTURY model Peng C and M J Apps 1998 Simulating carbon dynamics along the Boreal Forest Transect Case Study BFTCS in central Canada 2 sensitivity to climate change Global Biogeochemical Cycles 12 393 402 Probert M E B A Keating J P Thompson and W J Parton 1995 Modelling water nitrogen and crop yield for a long term fallow management experiment Australian Journal of Experimental Agriculture 3
109. potranspiration R Heterotrophic respiration Figure 1 9 General flaw diagram for the DAYCENT model 17 CENTURY Tutorial January 2001 2 Downloading and Installing the PC Version of CENTURY The PC standalone version of the CENTURY model and a Windows Help file version of the CENTURY manual can be downloaded from the CENTURY homepage http www nrel colostate edu projects century using a browser application such as Internet Explorer or Netscape Select the Download PC Century button on the CENTURY homepage This will take you to an ftp download site where you will see the files cent40 exe and README To download the files right click on the file icon and select the Copy to Folder option from the popup menu to save the file on your system Or you can download the PC standalone version of the CENTURY model and the CENTURY manual via anonymous ftp Open a DOS window by selecting Start Programs MS DOS Prompt from the Windows Start menu Use the cd command to change to the directory into which you wish to download the downloaded files Use the following ftp commands to download the CENTURY installation files ftp ftp nrel colostate edu anonymous lt your email address gt cd CENT century4 0 CENTX PC_VERSION bin prompt meget cent40 exe ascil mget README bye The file cent40 exe is an installation file that will install CENTURY its associated utility programs sample parameter and schedule files and the Windows Help file
110. r temperate crops ppdf 1 is approximately equal to the mean temperature of the warmest month ppdf 2 is 15 degrees higher 3 and 4 affect production mostly at the extremes values near 1 0 and 3 0 will serve adequately in most cases PARAMETER ppdf 1 2 ppdf 3 ppdf 4 MEANING Optimum Maximum Left Right temp temp shape shape Winter wheat barley Corn Soy bean C4 grass C3 grass Alfalfa VALUE CHOSEN Appendix 3 12 Appendix 3 CENTURY Parameterization Workbook 3 REDUCTION FACTORS CENTURY allows for growth to be restricted due to physical obstruction of above ground live and standing dead material Growth may also be reduced during the planting month Values for these parameters that we have used include bioflg 0 for crop 1 for grass biok5 1800 for crops 60 200 for grass pltmrf 0 4 0 5 for annual crops 1 for annual grass and 0 for perennial grass or crops see Fig 3 10 in the Century User s Manual fulcan 100 150 see Fig 3 10 in the Century User s Manual 4 ALLOCATION CENTURY accounts for variable allocation of C as plants mature The user specifies the initial allocation final allocation and the number of months after the planting month when the final value is reached These parameters only apply to crops and annual grasses see Fig 3 11 in the Century User s Manual frtc 1 0 4 0 6 for crops 0 for grass frtc 2 0 1 for most crops 0 for grass frtc 3 3
111. r decomposition on the Mauna Loa environmental matrix Hawai i patterns mechanisms and models Ecology 75 418 429 706 Wedin D A and D Tilman 1996 Influence of nitrogen loading and species composition on the carbon balance of grasslands Science 274 1720 1728 Woomer P L C A Palm J Alegre C Castilla D G Cordeiro K Hairiah J Kotto Same A Moukam A Riese V Rodrigues and M van Noordwijk 2000 Pages 99 115 in R Lal J M Kimball and B A Stewart editors Global Climate Change and Tropical Ecosystems CRC Press Inc Boca Raton Florida USA Xiao X D S Ojima and W J Parton Long term dynamics of Aneurolepidium chinese and Stipa grandis steppe ecosystems simulation of CENTURY model Researches on Grassland Ecosystems submitted Appendix 1 9 Appendix 1 Literature on CENTURY model Xiao X D S Ojima W J Parton and C Zuozhong 1993 Regional ecosystem database of Inner Mongolia China Proceedings of the Third International Workshop on Geographical Information Systems Beijing China August 20 23 Xiao X D S Ojima W J Parton and Z Chen 1996 Modeling of soil organic matter dynamics in eastern Inner Mongolia Pages 618 619 in Rangelands in a sustainable biosphere Fifth International Rangeland Congress Salt Lake City Utah USA Note The highlighted numbers represent the code number of that paper located at the Natural Resource Ecology Lab Colorado State University Appendix 1
112. ran stemp tave defac avh2o 1 stream 1 Plant Production Grass Crop Systems agcacc aglivc bglivc cgrain stdedc Forest Systems fcacc rleavc frootc fbrchce rlwodc crootc 54 CENTURY Tutorial January 2001 Soil C N P somtc tnetmn 1 tnetmn 2 tminrl 1 tminrl 2 somte 1 somte 2 The following flow diagrams can also be used as a guideline for selecting which output variables to extract from the CENTURY binary output file The output variable name for a pool is listed in the box representing the pool along with a short description of the value that variable represents 55 January 2001 CENTURY Tutorial uananpnigd upogo ojag uaseas GUAGE punog 610 180 1201415 1105 1201415 TW D3aadis 209015 Qvad eNIONYLS deuaypue sseJB aug Jo MDj 4 88 15 9 MA J53 MEH yaq 1008 10059 4 0 4 4 QOVOSH ulead 10048 H 13083 22 20 a nieto 105 EMUI WS 00892 uaneydiaaJg uaseag molo 1449 SANSA 1009 INS 1889 1905 LOOHS E 5 AINISIOLU 108 a1nje4auita agaua S d NEE LINISOS NIS OO
113. ratios co2ipr 2 is the multiplier that represent the effect of doubled CO on NPP co2ipr 2 1 3 co2itr 2 is the multiplier that represent the effect of doubled CO on transpiration rate co2itr 2 0 75 for deciduous and 0 9 0 95 for coniferous co2ice 2 i j is the multiplier that represent the effect of doubled CO on minimum and maximum C E ratios co2ice 2 i j 1 2 co2irs 2 is the multiplier that represent the effect of doubled CO on root shoot ratio co2irs 2 lt 1 3 Appendix 3 24 Appendix 3 CENTURY Parameterization Workbook 9 SAVANNA MODEL PARAMETERS CENTURY allows the user to simulate competition between trees and grasses If you are not simulating a savanna i e are only growing trees set the following 3 parameters to 1 basfc2 relates tree basal area to grass N fraction basfc2 0 5 basfct ratio between basal area and wood biomass basfct 400 sitpot relates grass N fraction to N availability This represents the above ground peak standing grass biomass without tree competition Units are pounds acre and values range from 1000 4000 sitpot 2400 10 OTHER PARAMETERS Check the parameters listed below and be sure they are set to the indicated values 0 5 15 to 28 laitop 113 Appendix 3 25 Appendix 3 CENTURY Parameterization Workbook fix 100 If you want to simulate the effects of changes in atmospheric CO concentration you must specify the initial part
114. rowing season accumulator for N uptake by plants for grass crop g m2 EUPBGA 1 Belowground growing season accumulator for N uptake by plants for grass crop g m2 EUPPRT 1 1 Growing season accumulator for N uptake by forest leaf component g m2 EUPPRT 2 1 Growing season accumulator for N uptake by forest fine root component g m2 EUPPRT 3 1 Growing season accumulator for uptake by forest fine branch component g m2 Appendix 2 9 Appendix 2 CENTURY Output Variables by Category EUPPRT 4 1 Growing season accumulator for uptake by forest large wood component g m2 EUPPRT 5 1 Growing season accumulator for N uptake by forest coarse root component g m2 FBRCHE 1 N in forest system fine branch component g m2 FERTOT 1 Accumulator for fertilizer FORSTG 1 Retranslocation N storage pool for forest FROOTE 1 N in forest system fine root component g m2 FRSTE 1 Sum of N in forest system live components RLEAVE 1 FROOTE 1 FBRCHE 1 RLWODE 1 CROOTE 1 g m2 FSYSE 1 Total N in forest system 1 sum of soil organic matter trees dead wood forest litter GROMIN 1 Gross mineralization of N LHZEAC 1 Accumulator for N inputs to 0 20 cm layer from the lower horizon pools associated with soil erosion g m2 1 1 Metabolic in surface litter g m2 9 1 Metabolic N in soil litter g m2 METMNR 1 1 Net mineralization
115. rs sch schedule file and save the output to a file named test bin you would enter the following at the command line century s c3grs n test The program will show the Model is running message and will return to the DOS prompt after completion Typing dir will show that test bin has been created LIST100 LIST100 is used to generate an ASCII text file listing of selected output variables from the binary file produced by a CENTURY run To run LIST100 enter the following command line at the DOS prompt in your working directory list100 and follow the on screen prompts Appendix 4 3 Appendix 4 CENTURY Command Lines Appendix 4 4
116. s a site network approach Lewis Publishers Chelsea Michigan USA Metherell A K 1992 Simulation of soil organic matter dynamics and nutrient cycling in agroecosystems Dissertation Colorado State University Fort Collins Colorado USA Metherell A K C V Cole and W J Parton 1993 Dynamics and interactions of carbon nitrogen phosphorus and sulphur cycling in grazed pastures Pages 1420 1421 in Proceedings of the XVII International Grassland Congress Metherell A K L A Harding C V Cole and W J Parton 1993 CENTURY Soil organic matter model environment Technical documentation Agroecosystem version 4 0 Great Plains System Research Unit Technical Report No 4 USDA ARS Fort Collins Colorado USA Metherell Cambardella W J Parton G A Peterson L A Harding and C V Cole 1995 Simulation of soil organic matter dynamics in dryland wheat fallow cropping systems Pages 259 2770 in R Lal J Kimball E Levine and B A Stewart editors Soil management and greenhouse effect CRC Press Inc Boca Raton Florida USA Motavalli P P C A Palm W J Parton E T Elliott and S D Frey 1994 Comparison of laboratory and modeling simulation methods for estimating soil carbon pools in tropical forest soils Soil Biology amp Biochemistry 26 935 944 1701 Ojima D S W J Parton D S Schimel and Owensby 1990 Simulated impacts of annual burning on prairie ecosystems Pages 118 132 in S L Coll
117. s per million co2ppm 1 and final parts per million co2ppm 2 of CO concentration and set co2rmp to specify a step 20 or ramp 1 function Most of the other parameters in the fix 100 should not be changed However some parameters may need to be adjusted to represent differences in C N ratios of SOM inputs for grasslands and forests and differences in P and S availability among various systems No other parameters in the fix 100 should be changed unless the user has strong experimental evidence to justify the change Appendix 2 5 in the Century User s Manual for definitions of parameters in the fix 100 file 1 FLOATING C N RATIOS IN SOM POOLS The parameters controlling the C N ratios may need to be adjusted from the default values particularly for temperate forest soils The default values listed in the table below are for grass crop soils and forest soils with a bulk C N lt 15 In most cases you will use the default values from the table If however your soil has a bulk C N gt 15 use the alternate values from the table Parameter Default Bulk soil C N 15 pcemic 1 1 16 16 pcemic 2 1 10 10 varatl 1 1 14 16 varatl 2 1 3 8 varat2 1 1 20 40 varat2 2 1 12 12 varat3 1 1 8 20 varat3 2 1 6 8 Appendix 3 26 Appendix 3 CENTURY Parameterization Workbook 2 OF NEWLY FORMED SOM The parameter radlp is used to adjust the C E ratio of newly formed slow SOM produced from surface active SOM This valu
118. sSdwvoowvad 5 NE BOCOM 9 9999 S d NE LIBIOOOAA 2L OOOAA SSHONTHE dyad 9301915394 1008 9791534 3ovJdadns Japauugns upn4f 10 moj g S do NEEL BLOONS nae aoe 2100842 aal 51008 454902 202924 951207 S d NE LISOONN TH jenuus AGOTA uaganpa4g uaugJg gurjjenuuy CX eB 000M 3o8v1 uaganpalg 10034 aui 25 OO Eg NIC LIBHOEH e PE SSeS SEE S3HONVHE am eadusa WAL unmgeidimalg AWON uiufirq ua TN 4 51009 S d NE LSANITTH 5997 14 CENTURY Tutorial January 2001 1 6 Use and Testing of the CENTURY Model Extensive data sets from long term agricultural experiments and grasslands have been used to test the CENTURY model We used the observed data to test the model and as a tool for integrating and interpreting the data sets Plant production and soils data from extensive tropical and temperate grasslands around the world Parton et al 1993 Gilmanov et al 1998 show that the model correctly simulated the effects of burning irrigation fertiliz
119. se a large proportion of total gas fluxes are often the result of short term rainfall snow melt or irrigation events and the processes that result in trace gas emissions often respond non linerly to changes in soil water levels DAYCENT and CENTURY both simulate exchanges of carbon and the nutrients nitrogen N and phosphorus P among the atmosphere soil and plants and use identical files to simulate plant growth and events such as fire grazing cultivation harvest and organic matter or fertilizer additions In addition to modeling decomposition nutrient flow soil water and soil temperature on a finer time scale than CENTURY DAYCENT also uses increased spatial resolution for soil layers DAYCENT includes submodels for plant productivity decomposition of dead plant material and SOM soil water and temperature dynamics and trace gas fluxes Figure 1 9 16 CENTURY Tutorial January 2001 DAYCENT MODEL SIRUCTURAL flows N GAS NOx Feedbacks information flows Processes designated by italics gt lt Control on process Stom Stomatal conductance H O Soil water content Death Plant component death 1 Soil temperature Decomp Decomposition 5 Soil texture Ninputs N Fixation N deposition N fertilization Carbon Nitrogen ratio of material Nitrification V Vegetation type Den Denitrification SOM Soil Organic Matter mineralization L Land use Eva
120. sed as the theoretical maximum net biomass production per month in terms of carbon NOT total mass Common values are 300 A00 g 3 3 CONTROLS ON PRODUCTION 3 a TEMPERATURE RESPONSES The effect of temperature on production is controlled by the parameter ppdf Typical values for generalized forest types are listed below the example genera listed are heavily northamericano biased and are general guidelines only For temperate forests ppdf 1 is approximately equal to the mean temperature of the warmest month ppdf 2 is at least 15 degrees higher ppdf 3 and ppdf 4 affect production mostly at the extremes 1 0 and 3 0 will serve adequately in most cases Select values for ppdf MBANING Optimum Maximum Left temp temp shape shape Arctic alpine shrub Boreal subalpine conifer i Northern hardwoods 27 45 1 0 3 0 Temperate conifer Pinus Juniperus Temperate hardwood 25 45 1 0 3 0 Quercus Carya etc Tropical and subtropical hardwood and conifer 29 Twp Appendix 3 18 Appendix 3 CENTURY Parameterization Workbook 3 b BIOMASS CHEMISTRY You have three options for calculating the biomass C E If you have actual carbon data instead of just biomass then use C data instead of the generalized carbon percentages listed below Select which option you prefer mark it with a check calculate the C E ratios and retranslocation controls and fill in the table with the values for
121. site def 22 CENTURY Tutorial January 2001 NOTE When running FILE100 the parameter definition files def must be in the directory from which you will be running FILE100 28 CENTURY Tutorial January 2001 4 Preparing for a CENTURY Simulation You will need to create a parameterization for you site Site specific information that 15 required for a CENTURY run includes monthly precipitation in centimeters monthly mean minimum temperatures in degrees Celsius monthly mean maximum temperatures in degrees Celsius site latitude and longitude sand silt and clay in top 20 cm layer of mineral soil bulk density of the top 20 cm layer of soil g cm 3 rooting depth and root distribution of the vegetation in cm best estimate of annual wet and dry N deposition C 1n the soil organic matter in the top 20 cm of soil N in the soil organic matter in the top 20 cm of soil Determine the type of system you will be simulating grassland cropping forest savanna You will need to know at least the following about the vegetation growing at your site in order to parameterize the model productivity of vegetation gC m 2 per year or growing season C N ratio of aboveground and belowground vegetation if modeling a crop grassland or split into leaves branches large wood fine roots and coarse roots for a forested system root to shoot ratio of vegetation if modeling a crop grassland or allocation of production to leaves branches large wood fin
122. site specific 100 file Enter the file name without the 100 extension EVENT100 checks to see that this file exists in the current directory and if so that the file is not empty If either of these error conditions is met the user may still go on Note however that CENTURY is no longer interactive in this respect and will not allow the name of the lt site gt 100 file to be re entered if the file does not exist or is not readable Enter the type of labeling to be done 0 No labeling 1 14C labeling 2 18C labeling stable isotope Default 0 No labeling Enter 0 1 or 2 If a value of 1 1s entered the next question will be In what year will labeling begin Enter a value greater than or equal to the simulation starting year If no labeling 15 to occur a zero will automatically be filled in for the year to begin labeling Enter Y if a microcosm is to be simulated Default N Enter a y or Y to indicate that a microcosm is to be simulated in CENTURY If a y or Y 15 entered a constant temperature must be entered 37 CENTURY Tutorial January 2001 Enter the constant microcosm temperature gt 0 Enter a temperature greater than or equal to 0 Enter Y if a CO2 effect is to be simulated Default N Enter a y or Y to indicate that a CO2 effect is to be simulated If a y or Y is entered the initial and final times for the effect to take place over must be entered Enter the initial time Enter the final
123. sm flag the effect flag initial crop and initial tree are displayed showing the original value from the schedule file the user may update any response to these questions A TIME command will automatically be executed to allow the user to update any block header information from the previous file Finally the display grid 1s shown with the previous events filled in Any changes may be made and any event or system commands may be entered Upon entering a SAVE or QUIT command the name of the schedule file given with the 11s used as the default 48 CENTURY Tutorial January 2001 5 39 CENTURY To run CENTURY use command line arguments as follows century s lt schedule file gt n lt binary output file gt lt schedule file gt is the schedule file you will be using without the sch extension and lt binary output file gt is the name that you wish to use for the file which will contain the output from your simulation run Do not include an extension on the lt binary output file gt name For example if you want to run the c3grs sch schedule file and save the output to a file named test bin you would enter the following at the command line century s c3grs n test The program will show the Model is running message and will return to the DOS prompt after completion Typing dir will show that test bin has been created 49 CENTURY Tutorial January 2001 5 4 LIST100 LIST100 is used to generate an ASCII text file listing of
124. st the abbreviations and descriptions found in the file Adding an option will allow the user to choose an existing option to copy and then allow the user to enter a new abbreviation and new values for the new option Changing an option will allow the user to change the abbreviation or any of the values associated with that option Deleting an option will completely remove the option from the 100 file Comparing shows the differences between options in the 100 file Each of these actions 1s described 1n more detail in the following sections Wan Entering a or quit at any point will return the user to the next highest menu 5 1 1 Reviewing All Options Review all options will print a list on the screen of the options found in that 100 file by listing each option s abbreviation and corresponding descriptions After reviewing the user may choose any of the five actions or return to the main menu to choose another 100 file Note that reviewing automatically causes the file to be re formatted to the specifications needed by the PC version of CENTURY 5 1 2 Adding an Option The user may choose to add a new option to the file After entering 2 for adding the program will display each option already existing in the file and ask if the user would like to begin with that option Current option is W1 Wheat type one Is this an option you wish to start with A response of Y or y will cause the program to copy this option to begin t
125. t 100 file are used ivauto 1 an equation for native grass soil initializes SOM pools ivauto 2 an equation for cropped disturbed soils initializes SOM pools nelem controls the number of elements you want to model For example nelem 1 means that P and S will not limit C flows C N nelem 1 C N P nelem 2 NP 6 nelem 3 sitlat lat deg N sitlng long deg E for reference only Appendix 3 2 Appendix 3 CENTURY Parameterization Workbook Enter the soil texture pH and bulk density for the top 20 cm of mineral soil for organic soils use top 20 cm enter actual mass fractions of sand silt and clay these need not total to 1 PROPERTY VALUE VARIABLE SAND fraction 0 1 SILT fraction 0 1 CLAY fraction 0 1 PH BULK DENSITY g cm Check the appropriate soil drainage class below and circle the corresponding value for the variable DRAIN Excessively to moderately well drained drain 1 0 Somewhat poorly drained drain 0 75 Poorly drained drain 0 5 Very poorly drained drain 0 25 No drainage from solum drain 0 0 TeC SOIL LAYERS Enter the rooting zone depth depth above which the large majority of fine roots are found cm Enter the soil thickness to be used for the soil water model For soils on deep saprolite or unconsolidated material enter the greater of rooting zone depth or depth to base of Bt For shallow soils enter depth to lithic contact For permafrost soils e
126. t all text to upper case Each event and system command is described in detail in the following section When all events have been entered use QUIT to save the scheduling to an output file and exit EVENT100 41 CENTURY Tutorial January 2001 5 2 5 Explanation of Event Commands Each event command is described in the following format XXXX The command name and explanation What additional information the command needs Mark How to schedule the event as occurring in the current month Unmark How to remove the scheduling of the event in the current month Output What the sch output file will show for this command CROPDesignates which crop is in use Acceptable abbreviations are from the crop 100 file Mark CROP addtl Unmark CROP X Output The year month and the word CROP followed on the next line by the crop selected PLTM Marks a month in which the current crop is planted Addtl This command has no additional it is simply marked or unmarked Mark PLTM Unmark PLTM Output The year month and the word PLTM HARV Designates which type of harvest to use automatically schedules a LAST event Addtl Acceptable abbreviations are from the harv 100 file Mark HARV Unmark HARV X Output The year month and the word followed on the next line by the harvest method selected FRST Marks the current month as the first month of growing for crops Addtl This command has no
127. t amount each year deposition 0 0 fixation 0 0 pitation vary linearly with annual preci dependence on average average precipitation annual annual fraction 0 1 deposition precipitation HO average EPNFA 2 average annual annual deposition precipitation g Nm dependence on average average precipitation annual annual fraction 0 1 fixation precipitation HO average annual precipitation average annual EPNFS 2 fixation Atmospheric deposition of S is simulated in the same manner as for N deposition above precipitation Average atmospheric deposition Input as a fixed satmos 1 satmos 2 with a slope and intercept based on annual You can choose fixed or variable S inputs wet dry g S m yr constant amount each year Average deposition 0 0 Have input vary linearly with annual precipitation satmos 2 satmos 1 dependence on average average precipitation annual annual fraction 0 1 deposition precipitation g S average satmos 2 average annual annual deposition 5 precipitation g Sm yr Appendix 3 5 Appendix 3 CENTURY Parameterization Workbook S can also be added in irrigation water If you are irrigating set Sirri equal to the S concentration mg S 1 of the water oherwise set sirri 0 2 SOIL BIOGEOCHEMISTRY 2 a INITIAL SO
128. t contains the list of output variables you want to extract from the binary file one variable per line For example if you want to look at the output variables aglivc bglivc agcacc and bgcacc create the following text file aglivc bglivc agcacc bgcacc Then if your binary filename is named test bin and you want LIST100 to create an ASCII file with the name test_out lis and you have saved a list of variable names in a file named var_list txt use the following command line to run LIST100 list100 test test out var list txt The start time and end time command line parameters are optional If you do not use them on the command line LIST100 will output all the information in the binary file from the time your simulation output begins to the time your simulation output ends If you want to restrict the output created by LIST100 to a specific part of the run enter a start time that 16 greater than or equal to the first year of output for the run and an end time that is less than or equal to the last year of output for the run as defined in the schedule file used for the run 63 CENTURY Tutorial January 2001 8 2 Run CENTURY Using a DOS Batch File You can automate CENTURY runs using a DOS batch file This is helpful if you have several runs to do Start by creating the DOS batch file using a text editor such as Windows Notepad or DOS Edit The file should contain the command lines for each of the CENTURY runs that you want to
129. t ratio increases the N content of live shoots and roots and returns nutrients to the soil Holland et al 1992 of the natural fire effects and standard forest management practices can be represented by the model selective logging clear cutting etc A complete description of the parameterization of the model for different plant systems and the use of the different management option 1s presented in the CENTURY User Manual Metherell et al 1994 12 January 2001 CENTURY Tutorial da4a ypue sseJD aug Jo moj 10128 4 ssalB AA Xepu jy ajey 1004 100 4 213 23108 alea upad 1004S HIJOS 4 4 ugseas Burm oio PUNO D Way 108 WS uananpo4g 1640 vOOHd2O uoseas 1449 JANSA 1201415 1009 1105 JANSY HI3083 LOOHS 1909015 5 Sus 20591 ONIGNYLS 108 AINE dwal JEquajod agaua g WS 1889 S d NEE LINISOS NIS OO 2 1 anbi 13 January 2001 CENTURY Tutorial Wos ATIS Wos D IN 92 S d NE LBEOOOQAA 51009 3
130. tab and then the Add button to add a new series Follow the steps outlined above to select the series data from your lis output file listing To modify other parts of the graph use the right mouse button and the popup menu or the Chart menu options from the main Excel menu 53 CENTURY Tutorial January 2001 7 CENTURY Output Variables CENTURY contains many output variables that you can examine but we have listed some of the important ones divided into categories First verify that the abiotic factors seem reasonable for the climate of your system If you have data for soil temperature or stream flow for example compare the measured values with the appropriate output variables Some of the output variables relating to plant production reflect growth while others reflect total biomass or biomass of plant parts Verify that plant growth and biomass are reasonable for your system Also verify that soil C N and P are reasonable For example mineral N should be low lt 1 during most of the year in native systems not subjected to high N inputs You should have some idea of total soil SOM C for your system to compare with the output variable somtc If any of these major outputs seem incorrect there is likely a problem in your schedule file your site file or your crop or tree file Consider various output variables to help diagnose your particular problem See Appendix 2 for output variable definitions Abiotic Factors precip pet evap t
131. ter g m2 Appendix 2 19 Appendix 2 CENTURY Output Variables by Category SOMSC Sum of labeled and unlabeled C from SOM1C SOM2C and g m2 SOMSCI 1 Sum of unlabeled C in SOM1C SOM2C and SOMSCI 2 Sum of labeled C in SOM1C SOM2C and SOM3C SOMTC Total soil C including belowground structural and metabolic g m2 SOMTCI 1 Total unlabeled C in soil including belowground structural metabolic SOMTCI 2 Total labeled C in soil including belowground structural metabolic STRCIS 1 1 Unlabeled surface litter structural C g m2 STRCIS 1 2 Labeled surface litter structural C g m2 STRCIS 2 1 Unlabeled soil litter structural C g m2 STRCIS 2 2 Labeled soil litter structural C g m2 STREAM 5 from organic leaching of stream flow base flow storm flow g m2 STRLIG 1 Lignin content of surface structural residue STRLIG 2 Lignin content of soil structural residue STRUCC 1 Surface litter structural C g m2 STRUCC 2 Soil litter structural C g m2 TOMRESY 1 Total unlabeled C in soil belowground and aboveground litter TOMRES 2 Total labeled C in soil belowground and aboveground litter TOTALC Total including source sink TOTC Minimum annual total non living C where total is SOM1C 1 SOM1C 2 SOM2C SOMSC STRUCC 1 STRUCC 2 METABC 1 METABC 2 Appendix 2 20 Appendix 2 CENTURY Output Variables by Category Sulf
132. ter chemistry texture and management Pages 147 167 in R B Bryant and R W Arnold editors Quantitative modeling of soil forming processes SSSA Spec Publ 39 ASA CSSA and SSA Madison Wisconsin USA 695 Parton W J P L Woomer and Martin 1994 Modelling soil organic matter dynamics and plant productivity in tropical ecosystems Pages 171 188 in P L Woomer and M J Swift editors The biological management of tropical soil fertility TSBF John Wiley amp Sons New York New York USA 741 Parton W J J M O Scurlock D S Ojima D S Schimel Hall Coughenour E Garcia Moya Gilmanov Kamnalrut J I Kinyamario T Kirchner T G F Kittel J C Menaut O E Sala R J Scholes and J A van Veen 1995 Impact of climate change on grassland production and soil carbon worldwide Global Change Biology 1 13 22 717 Parton W J D S Ojima and D S Schimel 1996 Models to evaluate soil organic matter storage and dynamics Pages 421 448 in M R Carter and B A Stewart editors Structure and organic matter storage in agricultural soils CRC Press Inc Boca Raton Florida USA 740 Appendix 1 6 Appendix 1 Literature on CENTURY model Parton W J 1996 Ecosystem model comparison science or fantasy world Pages 133 142 in D S Powlson P Smith and J U Smith editors Evaluation of soil organic matter models using existing long term datasets NATO ASI Series Vol 138 Springer Verlag Berlin Germa
133. the user to move among months and years to schedule crop type tree type planting and harvest months first and last month of growth for grassland or perennial crops senescence month cultivation fertilizer addition irrigation addition of organic matter straw or manure grazing fire tree removal and erosion To use EVENT100 make sure that the executable program event100 exe and the 100 data files are in the same directory To start the program enter event100 at the DOS prompt EVENT 100 includes the option of reading from a previously generated schedule file through the i option The schedule file must exist in the current directory and be of the name lt file gt sch Start EVENT100 by entering event100 i lt file gt at the DOS prompt Note that the sch extension is not included For example to modify a schedule file named c3grs sch enter the following command line event100 i c3grs Appendix 4 2 Appendix 4 CENTURY Command Lines Command Line Parameters for Running Century To run CENTURY use command line arguments as follows century s lt schedule file gt n lt binary output file gt lt schedule file gt is the schedule file you will be using without the sch extension and lt binary output file gt is the name that you wish to use for the file which will contain the output from your simulation run Do not include an extension on the lt binary output file gt name For example if you want to run the c3g
134. time Enter the initial time which must be greater than or equal to 0 and the final time which must be greater than the initial time Under what management was the site before the simulation began 1 Cropping Grassland 2 Forest 8 Cropping Grassland and Forest Default Cropping Grassland Enter the system which is to be simulated in CENTURY If answers 1 or 3 are chosen In order for the cropping system to run correctly you must specify an initial crop that will be used to initialize the lignin values Enter an initial crop Enter a crop choice this crop will be used by CENTURY to initialize the lignin content of standing dead surface and belowground litter pools before the actual simulation begins Hitting the return key will give a list of options from the crop 100 file If answers 2 or 3 are chosen In order for the forest system to run correctly you must specify an initial tree that will be used to initialize the lignin values Enter an initial tree Enter a tree choice this tree will be used by CENTURY to initialize the lignin content of the wood and litter pools before the actual simulation begins Hitting the return key will give a list of options from the tree 100 file 38 CENTURY Tutorial January 2001 The next few questions deal with setting up the first block Adding first new block Enter the starting year of simulation for this block The entered value must be greater than 0 Enter the last year of si
135. tion skewness values are not zero the precipitation values will be selected from a skewed distribution otherwise the precipitation values will be selected from a normal distribution Variables used are precip as means prcstd as standard deviations and preskw as skewness values these variables are the site specific lt site gt 100 file With both distributions precipitation for the month will equal zero if a negative value 16 stochastically generated Especially in the case of the normal distribution this will increase the mean annual precipitation above the sum of the monthly precip values F to use precipitation and temperature data from a new weather data file the weather file name must be no more that 8 characters and end with a wth extension The format of the weather file 1s a four character name field prec tmin or tmax two spaces a four character year field 12 number fields of the format 7 2 such that the length of each line is 94 characters For example prec 1915 0 31 2 55 5 07 7 01 8 87 5 13 1 61 8 83 3 55 3 53 0 99 0 92 tmin 1915 13 50 8 33 8 17 0 78 1 67 7 00 9 72 8 33 5 39 0 28 6 06 8 78 tmax 1915 4 44 8 56 4 33 16 33 17 50 21 06 26 83 26 06 22 89 18 89 10 78 8 50 1916 1 57 0 31 05 37 1 68 8 07 2 90 4 27 2 84 1 06 2 64 2 06 3 06 tmin 1916 16 50 9 50 4 89 2 28 1 56 6 28 10 56 9 89 3 33 2 44 9 28 14 78 tmax 1916 0 61 8 67 14 22 14 33 20 28 25 44 32 39 27 28 24 56 14 78 8 78 1
136. to start writing output the weather choice and the comment The user may append a block to the end of the current set or add a block previous to an existing one Addtl None Execute ABLK DBLK Deletes the current block and any grid values associated with the block The user is asked to double check that the block should be deleted Execute DBLK CBLK Copies the current block to a new block position The user 15 asked the block questions concerning the last year of simulation the number of years in the repeating sequence the data output interval value the month to start writing output the weather choice and the comment Execute CBLK 46 CENTURY Tutorial January 2001 TIME Allows the user to update values given in the interactive questions concerning block header information For each block set up the block header information is displayed and the user may update the responses Update Block Header Information Block Start End Out Out Out Wthr Wthr Comment Year Year Mnth Intv Type Name Field 1 1900 1950 1 1900 1 0 083 5 Grass 2 1951 1970 2 1951 d 0 083 F sidney wth W F Enter desired action Block number to start with ABLK to add a new block Q or return to quit DBLK to delete a block CBLK to copy a block If the user chooses to update any of the information shown each field 15 displayed with the old value and the user is allowed to enter a new value When Q or re
137. tural litter STRUCE 1 2 Surface litter structural g m2 STRUCE 2 2 Soil litter structural P g m2 SUMNRS 2 Annual accumulator for net mineralization of P from all compartments except structural and wood g m2 y 9 Total ratio in soil organic matter including belowground structural metabolic TEREM 2 Total P removed during forest removal events g m2 TMINRL 2 Total mineral P summed across layers g m2 TNETMN 2 Annual accumulator of net mineralization for P from all compartments g m2l y TOTALE 2 Total P including source sink W1MNR 2 P mineralized from the WOOD dead fine branch component of a forest system g m2 W2MNR 2 P mineralized from the dead large wood component of a forest system g m2 W3MNR 2 P mineralized from the WOOD3 dead coarse root component of a forest system g m2 WOODIE 2 P in WOODI dead fine branch component of forest system g m2 WOOD2E 2 P in dead large wood component of forest system g m2 WOODSE 2 P in WOODS dead coarse roots component of forest system g m2 WOODE 2 Sum of P in dead components of forest system g m2 Appendix 2 17 Appendix 2 CENTURY Output Variables by Category Soil Output Variables CLITTR 1 1 Surface unlabeled residue g m2 CLITTR 1 2 Surface labeled residue g m2 CLITTR 2 1 Soil unlabeled residue g m2 CLITTR 2 2 Soil labeled residue g
138. turn is entered all blocks are checked for time continuity and consistency Any errors found must be corrected before the user 1s allowed to return to the events grid Addtl None Execute TIME PREV Print a preview listing of the schedule file to the screen Addtl None Execute PREV DRAW Draws the display grid on the screen Addtl None Execute DRAW DRWA Draw Auto Toggle switch command that when on automatically draws the display grid after each event command 1s entered Otherwise the display grid 1s only drawn on a DRAW command The default is on the display grid is drawn after each event command Addtl None Execute DRWA HELP Displays a brief help message and where applicable the acceptable abbreviations from the specific 100 file An event or system command Execute HELP command SAVE Saves the scheduling to the output file name the user supplies If a previous SAVE command has been executed that file name will be displayed as a default the user may use that name or supply a new name The name of the output file will be lt file gt sch where file is the name supplied by the user Addtl EVENT100 will ask for an output file name Execute SAVE 47 CENTURY Tutorial January 2001 QUIT Terminates the 00 program Planting and harvest dates are tested for sequence correctness and symmetry first and last months of growth are likewise checked In the event that the user has a simulation i
139. ubmitted Frolking S E Mosier D S Ojima Li W J Parton C S Potter E Priesack Stenger C Haberbosch P Dorsch Flessa and Smith 1998 Comparison of 0 emissions from soils at three temperate agricultural sites simulations of year round measurements by four models Nutrient Cycling in Agroecosystems 52 77 105 Gijsman A J Hoogenboom W J Parton and P C Kerridge Modifying DSSAT for low input agricultural systems using a SOM module from CENTURY Agronomy Journal submitted Gijsman A J Oberson Tiessen and Friesen 1996 Limited applicability of the CENTURY model to highly weathered tropical soils Agronomy Journal 88 894 903 Appendix 1 2 Appendix 1 Literature on CENTURY model Gilmanov T G W J Parton and D S 1997 Testing the CENTURY ecosystem level model on data sets from eight grassland sites the former USSR representing wide climatic soil gradient Ecological Modelling 96 191 210 Hall D O D S Ojima W J Parton and J M O Scurlock 1995 Response of temperate and tropical grasslands to CO2 and climate change Journal of Biogeography 22 537 547 Hall D O J M O Scurlock D S Ojima and W J Parton 2000 Grasslands and the global carbon cycle modelling the effects of climate change Pages 102 114 in T M L Wigley and D S Schimel editors The carbon cycle Cambridge University Press Cambridge United Kingdom 948 Hartman M
140. ur Output Variables AGLIVE 8 S in aboveground live for grass crop g m2 AMINRL 3 Mineral S in layer 1 before uptake by plants BGLIVE 3 8 in belowground live for grass crop g m2 3 S in forest system coarse root component g m2 CRPSTG 9 Retranslocation S storage pool for grass crop g m2 EGRACC 3 Accumulator of S in grain tuber production for grass crop g m2 EGRAIN 8 Economic yield of S in grain tubers for grass crop g m2 EPRODC 8 Actual monthly S uptake for grass crop g m2 month EPRODF 3 Actual monthly S uptake in forest system g m2 month ERETA 3 Annual accumulator of S returned to system during grazing fire for grass crop g m2 year ERMVST 3 Amount of S removed as straw during harvest for grass crop g m2 month ESRSNK 8 5 source sink g m2 8 Growing season accumulator for S uptake by grass crop or tree g m2 EUPAGA 3 Aboveground growing season accumulator for S uptake by plants for grass crop g m2 EUPBGA 8 Belowground growing season accumulator for S uptake by plants for grass crop g m2 EUPPRT 1 3 Growing season accumulator for S uptake by forest leaf component g m2 EUPPRT 2 3 Growing season accumulator for S uptake by forest fine root component g m2 EUPPRT 3 3 Growing season accumulator for S uptake by forest fine branch component g m2 EUPPRT 4 3 Growing season accumulator for S uptake by forest
141. ure 1 6 11 January 2001 SHOW SNOW PET EN BARE SOIL EVAPORATION Atmosphere TRANSPIRATION TRAM AB Aboveground Biomass 9 m LE AF Live Leaf Biomass 9 PET Monthly Potential Evapotranspi ration crm PRECIP Precipitation cm Average Air Temperature CT STORMF Storm Flow BASEF Base Flow AVH20 2 Available HO in 60 depth 20 3 Available HO in plant rooting depth em Flow diagram for the water flow submodel CENTURY Tutorial January 2001 1 5 Plant Production and Management Model The CENTURY model is set up to simulate the dynamics of forests grasslands agricultural crops and savanna systems The grassland crop submodel Figure 1 7 simulates growth of different crops corn wheat potatoes sugarcane etc natural plant communities temperate warm and cool season grasslands tropical grasslands etc and managed grassland systems alfalfa clover and improved grasslands The forest submodel Figure 1 8 simulates the growth of evergreen pine and fir systems and evergreen tropical systems temperate deciduous and drought deciduous systems The savanna system simulates a tree grass system by simultaneously running the tree and grassland crop submodels with the submodels interacting through shading effects and nitrogen competition Both submodels assume that monthly maximum production is controlled by soll moisture and temperature with max
142. version of the manual on your PC To run the installation file select Start Run from the Windows Start menu and use the Browse button to locate the cent40 exe file which you have downloaded Once you have located the cent40 exe file select the Run button to start the installation process and follow the instructions on the screen The README file can be viewed using Windows Notepad and contains additional information about the installation file The executable files that will be installed are CENTURY EXE CENTURY executable EVENT100 EXE Event scheduler for CENTURY FILE100 EXE Parameterization utility LIST100 EXE Used to create ASCII output file This version of CENTURY runs from a DOS window in Windows 9x and Windows NT The 100 files are CENTURY parameter files The def files are definitions that go with the 100 files are will be used when you run FILE100 The sch files are sample schedule files 18 CENTURY Tutorial January 2001 With all of these files in one directory you should be able to run the model using the following command line in a DOS window after changing to the CENTURY directory century s lt sch file gt n out file gt sch file 1s the schedule file you will be using without the sch extension and out file 15 the name that you wish to use for the file which will contain the output from your simulation run Do not include an extension on the out file name For example if you want to run the c3grs sch s
143. water are added through irrigation How much and what type of organic amendment is added manure fish meal green manure Is your system flooded at any point during the year Etc Now decide the order and duration of the events and create a schedule file for your simulation 25 CENTURY Tutorial January 2001 5 Running CENTURY and its Utility Programs The PC version of CENTURY and its utility programs must be run from a DOS box in Windows 9x or Windows NT To open a DOS box select Start Programs MS DOS Prompt from the Windows Start menu Use the command to change to the directory where you CENTURY files are located For example when you open the DOS box you will most likely be in the Windows directory and the DOS prompt will show C NWINDOWS to change to the root directory enter the following command at the DOS prompt cd You should now be in the root directory In most cases the DOS prompt should now read C If you used the default CENTURY installation the CENTURY files will be in the C Ncentury directory To get to the CENTURY directory enter this command at the DOS prompt cd century If the command has executed successfully the DOS prompt will show C NCENTURY Use the dir command ensure that you are in the correct directory If you enter the command dir exe you should the CENTURY executable and its utility programs listed century exe event100 exe file100 exe list100 exe The usual sequence of events whe
144. while interception water loss increases with increasing aboveground biomass Transpiration water increases as a function of live leaf biomass Water loss occurs first as interception followed by bare soil water loss and transpiration with the sum not exceeding the potential evapotranspiration PET water loss PET is calculated as a function of maximum and minimum air temperature Precipitation in excess of PET is stored in soil water layers by adding the water to the top layer Near surface average soil temperature STEMP is used to calculate the abiotic decomposition rate and the temperature effect on plant growth STEMP is calculated using equations where the maximum soil temperature is a function of maximum air temperature and the canopy biomass lower for high biomass and the minimum soil temperature 15 function of minimum air temperature and canopy biomass higher for high biomass It 1s important to note that both the soil water balance and soil temperature models include the effect of simulated live and dead aboveground plant biomass on soil temperature and soil water balance 10 CENTURY Tutorial PRECIPITATIOH HTERCEPTIOH EVAP SOIL WATER 0 15 cm ASMOS a SOIL WATER 15 30 ASMOS ur 2 pact 30 45 ASMOS 13 45 60 ASMOS 4 SOIL WATER 50 90 ASMOS 5 STREAM FLOW STRE AM 1 DEEP SOIL STOR AGE ASMOSIB L Fig
145. wold 0 0 and fcfrac the same for i 1 and 2 Otherwise perform the following calculations for each forest type and set swold number of years after beginning of simulation when the forest changes from juvenile to mature fcfrac 1 i leaf production total NPP fcfrac 2 i fine root production total NPP fcfrac 3 i fine branch production total NPP 4 1 large wood production total fcfrac 5 i coarse root production total 6 BIOMASS TURNOVER RATES 6 a SET LEAF DEATH RATES Monthly leaf turnover is set in leafdr a deciduous or drought deciduous system the values of leafdr indicate mortality during the growing season from causes such as herbivory physical damage or early senescence The leaf mortality at the end of the growing season for deciduous or drought deciduous trees is determined by the value entered for wooddr 1 In an evergreen or semievergreen system leafdr indicates all leaf turnover including seasonal senescence and litterfall In any case these values are the fraction of leaves that are transferred to litter each month These values should be estimated from observed rates of litterfall in comparison to observed or estimated leaf biomass In deciduous and drought deciduous systems wooddr 1 is the fraction of leaves that are lost during the month of leaf drop For temperature deciduous systems the months of leaf out and leaf drop are controlled by temperature and
146. zons a le 1 2 1 som2ci 1 som3ci 1 clittr 1 1 por II Based on subhorizons somlci 1 1 somici 2 1 som2ci 1 clittr 1 1 E a quee uem perse emere quee RT prese n ae Ihe values calculated from simple horizons generally indicate the Steady state proportions of the soil pools around which the model will tend to settle over 1000 s of years Those based on horizons suggest non steady state values for younger or disturbed soils Usually they differ little except in organic very young or highly disturbed soils Appendix 3 7 Appendix 3 CENTURY Parameterization Workbook Examine the estimates for the initial pools on the previous page and enter values chosen below somici 1 1 C m somici 2 1 g C m som2ci 1 3 1 1 g cm clittr 1 1 g cm Unless you want to simulate isotope labeling all som ci 2 and clittr 2 parameters should be set to zero Sources for soil carbon data 2 b INITIAL SOM C N C P C S RATIOS Enter bulk C N C P C S ratios for SOM below make these calculations only for those elements you intend to simulate enter zeros for other elements a Litter or Forest floor C N C P C S b Mineral soil C N C P C S c TOTAL C N C P C S Calculate ratios for CENTURY pool VARIABLE EXPRESSION C N i 1 C P i 2 C S i 3

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