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1. Name ID Type Units Description APEX File Crop 5 YIn Single ke ha Nitrogen in crop yield apex OUT Crop 5 Ylp Single ke ha Phosphorus in crop yield apex OUT Crop 5 Fn Single t ha Nitrogen applied apex SUS Crop 5 Fp Single t ha Phosphorus applied apex SUS Crop 5 Water Stress Single days apex OUT Crop 5 Nitrogen Stress Single days apex OUT Crop 5 Phosphorus Single days apex OUT Stress Crop 5 Temperature Single days apex OUT Stress Crop 5 Curve Number Single none apex OUT Table B 2 Yearly Output Name ID Type Units Description APEX File Farm Id Long Integer none none apex OUT Yearly Integer none none apex OUT Subarea Integer none none apex OUT Area by Field Single ha apex OUT Tmx Single c Maximum Temperature apex OUT Prep Single mm Precipitation apex OUT Q Single mm Runoff apex OUT Prk Single mm Percolation apex OUT Yp Single kg ha Phosphorus loss with sediment apex OUT Ssf Single mm Subsurface flow apex OUT Rssf Single mm Subsurface flow that returns to apex OUT surface stream Yn Single kg ha Organic nitrogen loss with apex OUT sediment Qn Single kg ha NO3 loss in runoff apex OUT Ssfn Single kg ha Mineral nitrogen loss in apex OUT subsurface flow Prkn Single kg ha Mineral nitrogen loss in apex OUT percolate Gmn Single kg ha Gross nitrogen mineralized apex OUT Dn Single kg ha Nitrogen loss by denitification apex OUT Dprk Single mm Deep percolation apex OUT Nfix Single kg ha Nitrogen fixed by leguminous apex OUT crops Et Single
2. Parm 91 Parm 92 Parm 93 Parm 94 u A Parm 95 Parm 96 Parameters 8 Window See Appendix 1 Table 14 for APEX2110 parameters Appendix 3 for APEX0806 Parameters 8 in Figure 17 only includes the two remaining curve number variables that affect soil water content and calculation of the runoff curve number All other runoff curve number S Point Curve variables are addressed in the Parameters 1 and Parameters 2 windows in Figure 10 and 11 respectively Interactive APEX i_APEX USERS GUIDE 25 Figure 17 Parameters 8 Parameters Parameters 1 Parameters 2 Parameters 3 Parameters 4 Parameters 5 Parameters 6 Parameters 7 Parameters 8 1st 5 Point Curve 2nd 5 Point Curve Not Not Not Not used Soil water content CN2 CN3 Not Found SCRP1 26 Cancel Help Weather A weather station may be selected from the list that is resident in the ACCESS Weather and Weather by Month tables Graphical User Interface Window Figure 3 Measured daily weather data can be used in the simulations including Precipitation Maximum and minimum temperatures Solar radiation Average wind speed Average relative humidity AS If none of the daily weather parameters are available the Weather input code 0 Header 1 Figure 5 and all five weather parameters will be simulated by the APEX climate generator based on the selected weather station Header 1 Figure 5 Parameters that are used by
3. Annual pesticide dissolved and sediment SWAT Pesticide sorbed output to SWAT One record per Output apex SWT model subarea per day of loss Watershed One record per run per Output apex OUT Watershed data month apex OUT One record per Yearly Output apex SUS General run data by year subarea per year ACCESS Database Links Thei APEX ACCESS database consists of a series of linked tables that contain input and output data Figure 2 Four support tables Crops Fertilizer Operations and Pesticide are linked to the Field Operations table and the Selected Variables table which is linked to the Average Output and Yearly Output tables All other tables are linked to either the Control Records table or the Subarea table which is also linked to the Control Records table Note Selection and data changes to any ACCESS table will not be shown ini APEX until ACCESS andi APEXis exited followed by re executing i APEX Interactive APEX i APEX USERS GUIDE 5 Figure 2 Database Layout SWAT Pesticide Output SWAT Output 2 Weather Weather Station ID Weather by Month Staton ID Pesticides Tables containing standard 7 APEX support datasets linked by various field operation codes 6 Interactive APEX i_APEX USERS GUIDE Getting Started i_APEX Graphical User Interface 1 Executing i APEX can be achieved by clicking on the i APEX icon ori APEX exe This will bring up the graphic interface Figure 3 Figure 3
4. Figure 14 Parameters 5 Parameters Parameters 1 Parameters 2 Parameters 3 Parameters 4 Parameters 6 Parameters 7 Parameters 8 Root temperature stress jas Water storage of residue coef SCS curve number coefficient fi 5 Tillage effect on decay rate Plow layer depth 01 5 Oxygen eq microbial activity Curve number retention limit fi 5 Routing N enrichment ratio Sediment routing travel time coef E Routing N enrichment exp RUSLE C factor coef residue 05 Fraction destroyed by burn RUSLE C factor coef biomass 0 01 Routing P enrichment ratio coef ate Adjust climate stress factor o Routing P enrichment ratio exp _ Canopy rainfall interception jo P upward by evaporation Rainfall interception coef 01 Max grazing before rotation TA ie Cancel Help Parameters 6 Window See Appendix 1 Table 14 for APEX2110 parameters Appendix 3 for APEX0806 Parameters 6 in Figure 15 includes variables regarding soil water variables puddling nitrogen and phosphorus dynamics manure erosion enrichment ratios to SWAT inputs pesticide loss coefficient and delay of application due to soil saturation dust variables microbial activity furrow irrigation variables standing dead fall rate conversion to flat residue coefficient runoff delay pest applicate technology coefficient harvest index adjustment to year 2000 Oo Oo Oo Oo Oo Oo Oo Oo Oo e rainfall intensity and lateral hydraulics Interactive APEX i_APEX U
5. Graphical User Interface Window Ti APEX new_watersheds mdb i a of x File Edit View Window Select Run Record Help e ujaj a r ee ee Record 1 of 88 ID Po State FIPS fo County FIPS jo A ubareas MLRA HUC ms PSU o Point jo NRI Pointer o Application Category fo Run Header Nutrient Rate Category fo Parameters fo Application Timing Erosion equation MUSLE modified USLE Weather Station UMPWY Select Edit l Running APEX2110 1 ID 1 2 Select File after the i APEX window appears The user may select a file from the menu and can either create an empty database by selecting New or select Open and go to the subdirectory containing your i APEX files and click on the desired i APEX file such as the example file new_watersheds mdb provided when downloading i APEX Interactive APEX i_APEX USERS GUIDE 7 Note If instead of selecting Open the user clicks on File and selects one of the files from the list of previously used files a window may appear with the message ERROR unable to open help file iApexHelp csv This will result in definitions of variables not appearing at the bottom of each i APEX screen The execution interface consists of the following four discrete sections 1 Menu 2 Tool bar 3 Control record list on the left below the menu and toolbar and 4 Edit area to the right of the control record list
6. RETENIDOS EE N E A ANE AE ET 37 Appendix A ACCESS 1 APEX Input Tables oooooonnccinonincnnocnnonnconcconccon ccoo nononoco noc noconocanrrnnnonnrs 39 Appendix B ACCESS I APEX Output Tables 0 cc cccecceescseceeeeeeseeeseeeseecseeeseeseeeeeeeeeeseneeses 55 Appendix C APEX0604 and APEX0806 Miscellaneous Parameter Table Definitions 63 List of Figures Figur ti APEX Flow Chart seis 5454 8se aa 4 Figure 2 Database Lay Out 14 554440 canted eevee dante Stanev A aa 6 Figure 3 Graphical User Interface Window mirenmseenaeennenenenenenenenenennnnennnennneenaeenneeeneeea 7 Figure 4 Configuration Window sreerenrenmnenmsennseenreeneenntenneenneeneneneneneneneneennnennnenne et 12 Figure A A A SST 14 Figure 6 Hleader 24 155 8 rt sttgalkitatta beds ablad tal Seati dae dau AE ET 15 Eigure 7 Hed nata E a a lia iii 16 Figure 8 Header 4 usada ii aiii 17 Figure V A E SN 18 Figure 10 Parameters Dioni radiata ida 19 Figure 11 Parameters A a e A A n AEn ON aR 20 Figure 12 Parameters Zincare iiei entar TT 21 Figure 132 Parameters di as 22 Figure 14 Parameters ld taa an aata adra val deataatedsanevadesas did i n 23 Figure 15 Parameters Ori A kaela a Snake sakala maata ka 24 Figure 16 Parameters Tira id dd s ti pads kaela aata nae Ain 25 Eigure 17 PATAS Vii a a a a r ested aee e a aaaea 26 Figure 18 Subarea Edit Windowse e a E E E E E E E E 31 Figure 20 Subarea Fiel
7. RR Top Width of Channel Single m rctw iasub dat RR Slope Single m m rchs iasub dat RR Mannings N for Channel Single none rchn iasub dat RR USLE C for Channel Single none rchc iasub dat RR USLE K for Channel Single none rchk iasub dat RR Floodplain Width Single m rfpw iasub dat RR Floodplain Length Single km rfpl iasub dat RS Surface Area at Emergency Single ha rsae iasub dat Spillway RS Volume at Emergency Single mm rsve iasub dat Spillway Elev RS Initital Volume Single mm TSV iasub dat RS Principle Spillway Release Rate Single mm h rsrr iasub dat RS Initial Sediment Concentration Single ppm rsys iasub dat RS Normal Sediment Concentration Single ppm rsyn iasub dat RS Bottom Hydraulic Conductivity Single mm h rshc iasub dat 42 Interactive APEX i APEX USERS GUIDE Table A 3 continued Name ID Type Units Description APEX File RS Time Required to Return to Single days rsdp iasub dat Normal Sediment Conc RS Bulk Density Single t m 3 rsbd iasub dat Land Use Number Integer none lun nnnn ops Hydraulic Condition Integer none nnnn ops Autoirrigation Number Long Integer none laua iasub dat used to calculate curve number for plant operation Table A 4 Management Name ID Type Units Description APEX File Subarea Id Long Integer none iasub dat Irrigation Rigidity Integer none irr iasub dat Irrigation Long Integer none irr iasub dat Minimum Auto Irrigation Long
8. pesticide list iacrop dat crop details list iaOptList dat operation filenames nnn ops field operations iaS1List dat soil filenames nnn sol soil data iawthist dat weather filenames iaweath dat precipitation data iawind dat weather station data iasublist subarea filenames iasublist dat subarea filenames iawndlst dat wind filename iasitels dat iasub dat subarea file 4 Interactive APEX i_APEX USERS GUIDE Table 2 ACCESS Database Output Tables Corresponding Table Name Apex Output File Table Contents Table Structure Annual Pesticide Hydrology data pertinent One record per Output apex APS to pesticide losses subarea per year Annual Pesticide One record per Output 2 apex APS Pesticide losses subarea per year apex OUT One record per run per Average Output apex SUS General run data subarea Crop Yield One record per Output apex ACY Crop yield data subarea per year Monthly SWAT Monthly outputto SWAT One record per Output apex MSW model subarea per month Organic C and N One record per Output apex ACN Soil layer C and N data subarea per year One record per Residue Output apex OUT Crop residue subarea per month Annual hydrology and dissolved nutrient output One record per SWAT Output apex SWT to SWAT model subarea per day of loss Annual sediment and nutrient associated with sediment output to One record per SWAT Output2 apex SWT SWAT model subarea per day of loss
9. 4 Single various apex OUT Selected Variable 5 Single various apex OUT Selected Variable 6 Single various apex OUT Selected Variable 7 Single various apex OUT Selected Variable 8 Single various apex OUT Selected Variable 9 Single various apex OUT Selected Variable 10 Single various apex OUT Number Crops Integer none apex OUT Crop 1 Id Text none apex OUT Crop 1 Yield Single t ha apex OUT Crop 1 Biomass Single t ha apex OUT Crop 1 YIn Single kg ha Nitrogen in crop yield apex OUT Crop 1 Ylp Single kg ha Phosphorus in crop yield apex OUT Crop 1 Fn Single t ha Nitrogen applied apex SUS Crop 1 Fp Single t ha Phosphorus applied apex SUS Crop 1 Water Stress Single days apex OUT Crop 1 Nitrogen Stress Single days apex OUT Crop 1 Phosphorus Single days apex OUT Stress Crop 1 Temperature Single days apex OUT Stress Crop 1 Curve Number Single none apex OUT Crop 2 Id Text none apex OUT Crop 2 Yield Single t ha apex OUT Crop 2 Biomass Single t ha apex OUT 56 Interactive APEX i APEX USERS GUIDE Table B 1 continued Name ID Type Units Description APEX File Crop 2 YIn Single kg ha Nitrogen in crop yield apex OUT Crop 2 Ylp Single ke ha Phosphorus in crop yield apex OUT Crop 2 Fn Single t ha Nitrogen applied apex SUS Crop 2 Fp Single t ha Phosphorus applied apex SUS Crop 2 Water Stress Single days apex OUT Crop 2 Nitrogen Stress Sing
10. APEX output files and fills the appropriate output tables in the ACCESS database Figure 1 ACCESS input tables are organized by field operations management soil properties weather pesticide properties and fertilizers for each subarea Table 1 Each input table may be edited directly in ACCESS or edited within the i APEX editing respective screens Output tables consist of monthly and annual crop yields watershed output except for pesticides and annual pesticide output Table 2 ACCESS input table formats are presented in Appendix 1 tables and output table formats are shown in Appendix 2 tables Each i_ APEX graphical interface screen is organized by aspects of farming categories and correlate with multiple ACCESS tables i APEX interface screens tabs and buttons are organized in the following schema i_APEX buttons are bracketed and bolded e Graphical User Interface e Menu selections e File e Configuration e Edit e View e Window e Select e Run e Record e Help e Tool Bar e Run Header e Header 1 e Header 2 e Header 3 e Header 4 e Header 5 e Parameters Parameters 1 e Parameters 2 Parameters 3 Parameters 4 Parameters 5 Parameters 6 Parameters 7 Parameters 8 Weather Station Select Edit Subareas 1 2 3 2 Interactive APEX i_APEX USERS GUIDE e Soil Select Edit Tillage suggestion change name to Field Operations Chang
11. Control Record Listean a A A A E 12 Edt At Cabins NR 12 Record IDs iii ane na ck enue a ae Ae Al A RR ba Ae BA TT 13 A A Ce a a Pe Pr re ON 13 H ader 1 WindoW nt td o a 13 Header Wind Wisin ld cio laes mal 14 Header WII Wii a MO Le SRE E a A 15 Header E Wind RT A SA A RT TE 16 Header WIMAOW 1545 n E ia 17 Parameter Wind OWS isos sio idiotas 18 Parameters 1 Windo Wet cad idad 18 Parameters 2 Window coil iodo a e saua avaus kavad 19 Parameters O enne 20 Parameters 4 WINdO Witt lia 21 Parameters 3 Window ennaa tc cli sobacesashs eauabenc beast OAAS 22 Parameters 6 WindOW cccccccccssssccecesssececsessececsesseeecsssseeecessseeecsessssecsessesecsessseeesssssecesesseeessnas 23 Parameters 7 Wind OW eaa AEE kei vise sdai ki keskne Sveta 24 Parameters 8 WindOW ccccccccssssscccsessececesseeecsesseeecsesseeccsssseeecsesseeecsesseeecsessesecsesseecesesseeeessnss 25 W CAN A E TE T A EATA EE 26 SL A EE A A EEE E aed Mae E NT 27 Erosion Sedino ea A aA A AAE AAAA aain 27 Hydrol RR RON 28 RODO A addict 28 A A E E EE 28 Evapotranspitationiesses cease aa 29 Fern Zeti NO 29 Pesticidas aia sia RA O aA 30 SUDALCAS da al dlls ETA DAEA 30 S bareas ROUDE renne A T E Saha E E eis dad aE 31 Subareas Floodplains and Filter Strips cccccscesscesseesseeeseeeeeeeeeeeeseecsseenseceaeeneeseeeeeeeeeeeeeaes 32 Subarea Field Operation iia ii 33 Calibration and Validation of APEX Using i APEX wrnienenennenmre nene 34
12. DISTRIBUTION DISPERSION EXPONENT 5 0 15 0 MODIFIES THE EFFECT OF THE ANGLE BETWEEN THE WIND DIRECTION AND THE CENTROID OF DOWNWIND SUBAREAS PRMT 68 MANURE EROSION EXPONENT 0 1 1 0 MODIFIES EO BASED ON WEIGHT OF MANURE ON SOIL SURFACE PRMT 69 COEF ADJUSTS MICROBIAL ACTIVITY FUNCTION IN TOP SOIL LAYER 0 1 1 PRMT 70 MICROBIAL DECAY RATE COEF 0 5 1 5 ADJUSTS SOIL WATER TEMPERATURE OXYGEN EOUATION PRMT 71 MANURE EROSION COEF 1 0 1 5 MODIFIES EROSION ESTIMATE BASED ON ABOVE GROUND PLANT MATERIAL PLANT MATERIAL LIVE AND DEAD REDUCE MANURE EROSION PRMT 72 VOLATILIZATION NITRIFICATION PARTITIONING COEF 0 05 0 5 FRACTION OF PROCESS ALOCATED TO VOLATILIZATION PRMT 73 HYDROGRAPH DEVELOPMENT PARAMETER 0 1 0 9 STORAGE DEPLETION ROUTING EXP USED TO ESTIMATE TRAVEL TIME OUTFLOW RELATIONSHIP PRMT 74 PARTITIONS N FLOW FROM GROUND WATER 0 0 20 0 PRMT 74 NCH NCV RSFN RSSF NCH DPKN DPRK NCV 70 Interactive APEX i APEX USERS GUIDE PRMT 75 P ENRICHMENT RATIO FOR DELIVERY TO SWAT 0 05_ 1 5 ENRICHMENT RATIO FOR APPLICATION TO 8 DIGIT SEDIMENT YIELD SUPPLIED TO SWAT PRMT 76 STANDING DEAD FALL RATE COEF 0 0001_0 1 GOVERNS RATE OF STANDING DEAD CONVERSION TO FLAT RESIDUE PRMT 77 RAINFALL AMOUNT TO DELAY PEST PPLICATION MM 0 0_ 25 0 PESTICIDE IS NOT APPLIED ON DAYS WITH RAINFALL GREATER THAT PRMT 77 PRMT 78 SOIL WATER VALUE TO DELAY TILLAGE 0 0 1 0 TILLAGE DELAYED WHEN PDSW FCSW gt
13. Interactive APEX i_APEX USERS GUIDE Table A 5 continued Name ID Type Units Description APEX File Int Variable Integer none jx 7 nnnn ops Parameter 1 Single Variable opvl nnnn ops Parameter 2 Single Variable opv2 nnnn ops Parameter 3 Single Variable opv3 nnnn ops Parameter 4 Single Variable opv4 nnnn ops Parameter 5 Single Variable opv5 nnnn ops Parameter 6 Single Variable opv6 nnnn ops Parameter 7 Single Variable opv7 nnnn ops Table A 6 Soils Name ID Type Units Description APEX File Name Text none afx nnnn sol Soils 5 Id Text none none nnnn sol Hydrologic Group Single none hsg nnnn sol Number of Layers Integer none none nnnn sol Weathering Code Integer none xids nnnn sol Albedo Single none salb nnnn sol Initial Water Content Single none ffc nnnn sol Minimum Water Table Depth Single m wtmn nnnn sol Maximum Water Table Depth Single m wtmx nnnn sol Initial Water Table Depth Single m wtbl nnnn sol Subsurface Flow Travel Time Single days rftt nnnn sol Initial Groundwater Storage Single mm gwst nnnn sol Maximum Groundwater Storage Single mm gwmx nnnn sol Return Flow Root Zone Single rfpk nnnn sol Maximum Layers Single none tsla nnnn sol Previous Years Cultivation Single years rtn1 nnnn sol Soil Group Type Single none xids nnnn sol Minimum Thickness of Maximum Single m zqt nnnn sol Layer Minimum Profile Thickness Single m zf nnnn sol Minimum Beginning Layer Single m ztk nnnn sol Thickness Fraction
14. MSW SUS APS and ACN These files must be checked to receive output in their respective database tables All output is expressed in metric units by default Output may be generated in English units by checking the Convert output to English Unit box The number of years of output can be designated in the last line of Configuration by typing the beginning and ending years in Save output for first year through last year Finally selecting the OK button saves all variable designations Interactive APEX i APEX USERS GUIDE 1 1 Figure 4 Configuration Window RaALivestock i_apex MSYC 8 run_apex apex0806 exe Jv Prebuild Control Record List Prebuild soil list C Apex2110 Apex0604 Apex0806 m Selected Output Variables 1 TMX Max temperature 2 TMN Min temperature 3 SRAD Solar radiation 4 PRCP Precipitation 5 SNOF Snowfall 6 SNOM Snowmelt 7 WSPD Wind Speed 8 RHUM Relative Humidity 9 YPD Vapor Pres Deficit 17 PFT Potential FT _apex Selected User Selected 100 RFY 107 RUSL Select Variable 12EP 19 QIN Remove 26 USLE 29MUSS 36 YWND 44 NIKANI Control Record List The control record list from the Control Records table is sequenced starting with the control record 1 which may or may not be control record ID 1 Table 3 A Control Record can be created by clicking on an existing sample record and modifying it as desired or generating a new record by using the tool bar con
15. Menu 1 File New create an empty database Open open an already existing database Close close the resident database Import APEX files import APEX files into the current database The user may import APEX input file records and add delete or edit existing records APEXFILE DAT imports a complete set of APEX files into the current database 1 APEX determines the file names from the apexfile dat file Pesticide File imports the APEX pesticide file into the Pesticide table of the current database Fertilizer File imports the APEX fertilizer file into the Fertilizer table of the current database Crop File imports the APEX crop file into the Crop table of the current database Operations File imports the APEX operations file into the Operations table of the current database Parameter File imports the APEX parameter file into the parameter table of the current database Import Area Studies Files used to import more APEX files Operations File imports an APEX operations schedule file into the Field Operations table of the current database Soil imports an APEX soil file into the Soil and Soil Layer tables of the current database Weather File imports an APEX weather file into the Weather table and Weather by Month table of the current database Wind File imports an APEX wind file into the Weather by Month table of the current database Export Output not presently functionin
16. ON HARVEST INDEX AS A FUNCTION OF PLANT WATER USE X PLANT WATER USE DURING CRITICAL PERIOD SCRP 11 N GOVERNS P USE BY PLANTS AS A FUNCTION OF SOIL P CONCENTRATION X SOIL LABILE P CONCENTRATION SCRP 12 N GOVERNS N VOLATILIZATION AS A FUNCTION OF SOIL DEPTH X DEPTH AT THE CENTER OF A SOIL LAYER MM SCRP 13 N CALCULATES WIND EROSION VEGETATIVE COVER FACTOR AS A FUNCTION OF ABOVE GROUND PLANT MATERIAL X VEGETATIVE EQUIVALENT C1 BIOM C2 STD C3 RSD WHERE Cl C2 AND C3 ARE COEFFICIENTS BIOM IS ABOVE GROUND BIOMASS STD IS STANDING DEAD PLANT RESIDUE AND RSD IS FLAT RESIDUE SCRP 14 N CALCULATES SOIL TEMPERATURE FACTOR USED IN REGULATING MICROBIAL PROCESSES X SOIL TEMPERATURE C SCRP 15 N ESTIMATES PLANT POPULATION EFFECT ON USLE C FACTOR X PLANT POPULATION P M 22 SCRP 16 N INCREASES SNOW MELT AS A FUNCTION OF TIME SINCE THE LAST SNOWFALL X TIME SINCE THE LAST SNOWFALL D SCRP 17 N COMPONENT OF THE PLANT WATER STRESS FACTOR BASED ON SOIL WATER CONTENT X RATIO OF ROOT ZONE SOIL WATER CONTENT TO PLANT AVAILABLE WATER STORAGE VOLUME SCRP 18 N ADJUSTS CN2 AS A FUNCTION OF UPLAND SLOPE STEEPNESS X UPLAND SLOPE SCRP 19 N REGULATES FEEDLOT DUST EMISSION BASED ON MOISTURE CONTENT OF LITTER X WATER IN LITTER WEIGHT OF LITTER SCRP 20 N SIMULATES OXYGEN CONTENT OF SOIL AS A FUNCTION OF DEPTH USED IN MICROBIAL PROCESSES OF RESIDUE DECAY X DEPTH TO CENTER OF
17. PRMT 78 PRMT 79 AUTO MOW LOWER LIMIT T HA 0 2_3 AUTO MOW DELAYED UNTIL ABOVE GROUND PLANT MATERIAL EXCEEDS PRMT 79 PRMT 80 UPPER LIMIT OF NITRIFICATION VOLATILIZATION 0 0_0 5 FRACTION OF NH3 PRESENT PRMT 81 TECHNOLOGY COEF 0 0_0 01 LINEAR ADJUSTMENT TO HARVEST INDEX BASE YEAR 2000 PRMT 82 NOT USED PRMT 83 ESTIMATES DRAINAGE SYSTEM LATERAL HYDRAULIC CONDUCTIVITY 0 1_ 10 0 DRAINAGE HCL IS MAXIMUM OF PRMT 83 VERTICAL SC AND APEX ESTIMATE CONSIDERING DRAINAGE TIME AND STORAGE HCL L ISA MAX PRMT 83 SATC L ISA PO L ISA S15 L ISA 24 DRT ISA PRMT 84 COEF REGULATING P FLUX BETWEEN LABILE AND ACTIVE POOL 0 0001 0 001 RMN PRMT 84 WPML ISL ISA WPMA ISL ISA RTO PRMT 85 COEF REGULATING P FLUX BETWEEN ACTIVE AND STABLE POOL 0 0001 0 001 ROC PRMT 85 BK ISL ISA 4 WPMA ISL ISA WPMS ISL ISA PRMT 86 NUPWARD MOVEMENT BY EVAPORATION COEF 0 001 20 BASE VALUE 1 0 RELATED DIRECTLY TO UPWARD MOVEMENT PRMT 87 WATERTABLE RECESSION COEF 0 001_ 1 0 SMALL VALUES SLOW THE WATERTABLE RECESSION PRMT 88 LIMITS DAILY WATERTABLE MOVEMENT 0 001 1 0 FRACTION OF DIFFERENCE BETWEEN WTBL AND WTMN OR WTMX PRMT 89 WATERTABLE RECESSION EXPONENT 0 1_0 9 EXPONENT OF DAY OF YEAR 365 PRMT 90 REGULATES LATERAL SUBSURFACE AND QUICK RETURN FLOW 0 1 10 LARGE VALUES INCREASE FLOW Interactive APEX i APEX USERS GUIDE 771 PRMT 91 REGULATES EVAPORATION FROM CHANNEL a
18. Single kg ha Nitrogen in crop yield apex OUT Crop 3 Ylp Single kg ha Phosphorus in crop yield apex OUT Crop 3 Fn Single t ha Nitrogen applied apex SUS Crop 3 Fp Single t ha Phosphorus applied apex SUS Crop 3 Water Stress Single days apex OUT Crop 3 Nitrogen Stress Single days apex OUT Crop 3 Phosphorus Single days apex OUT Stress Crop 3 Temperature Single days apex OUT Stress Crop 3 Curve Single none apex OUT Number Crop 4 Id Text none apex OUT Crop 4 Yield Single t ha apex OUT Crop 4 Biomass Single t ha apex OUT Crop 4 YIn Single kg ha Nitrogen in crop yield apex OUT 60 Interactive APEX i_APEX USERS GUIDE Table B 2 continued Name ID Type Units Description APEX File Crop 4 Ylp Single kg ha Phosphorus in crop yield apex OUT Crop 4 Fn Single t ha Nitrogen applied apex SUS Crop 4 Fp Single t ha Phosphorus applied apex SUS Crop 4 Water Stress Single days apex OUT Crop 4 Nitrogen Single days apex OUT Stress Crop 4 Phosphorus Single days apex OUT Stress Crop 4 Single days apex OUT Temperature Stress Crop 4 Curve Single none apex OUT Number Crop 5 Id Text none apex OUT Crop 5 Yield Single t ha apex OUT Crop 5 Biomass Single t ha apex OUT Crop 5 YIn Single ke ha Nitrogen in crop yield apex OUT Crop 5 Ylp Single ke ha Phosphorus in crop yield apex OUT Crop 5 Fn Single t ha Nitrogen applied apex SUS Crop 5 Fp Single t ha Phosphorus applied apex SUS C
19. Single none bchl iasite dat Basin Channel Slope Single none bchs iasite dat Atmospheric CO2 Single none co2x iasite dat Irrigation Water NO3 Single none cqnx iasite dat N in Rainfall Single none rfnx iasite dat Weather 1 Integer none impw 2 iasite dat Weather 2 Integer none impw 3 iasite dat Weather 3 Integer none impw 4 iasite dat Weather 4 Integer none impw 5 iasite dat Weather 5 Integer none impw 6 iasite dat Weather 6 Integer none impw 7 iasite dat Weather 7 Integer none impw 8 iasite dat Weather 8 Integer none impw 9 iasite dat Weather 9 Integer none impw 10 iasite dat Fraction of Area by Weather 1 Single none fwxp 1 iasite dat Fraction of Area by Weather 2 Single none fwxp 2 iasite dat Fraction of Area by Weather 3 Single none fwxp 3 iasite dat Fraction of Area by Weather 4 Single none fwxp 4 iasite dat Fraction of Area by Weather 5 Single none fwxp 5 iasite dat Fraction of Area by Weather 6 Single none fwxp 6 iasite dat Fraction of Area by Weather 7 Single none fwxp 7 iasite dat Fraction of Area by Weather 8 Single none fwxp 8 iasite dat Fraction of Area by Weather 9 Single none fwxp 9 iasite dat Weather Input File Name Single none fwth iasite dat Table A 2 Livestock Name ID Type Units Description APEX File Owner Id Long Integer none iasite dat Herd Id Integer none iasite dat Number of Animals Integer none ncow iasite dat Fraction Herd in Feeding Area Single none ffed iasite dat Grazing Rate Single kg hd d gzrt iasit
20. be chosen to represent typical field configurations ofthe area Efforts to match field dimensions and drianage area are not v coca m Parameter Windows Eight parameter windows display supporting variables and coefficients relative to hydrology crops soils nutrients field operations erosion and pesticides All variables have been assigned preexisting defaults Generally these defaults may be used in performing runs unless the expert user has more accurate information that is specific to a field watershed or region Some of the variables and coefficients are particularly sensitive and are useful during calibration and validation of the model This will be addressed in the calibration validation section The box at the bottom of each parameters window contains the parameter definition for APEX2110 Definitions for APEX0806 may be slightly different APEX2110 definitions are located in Appendix 1 Table 14 APEX0806 definitions are in Appendix 3 Parameters 1 Window See Appendix 1 Table 14 for APEX2110 parameters Appendix 3 for APEX0806 Parameters 1 in Figure 10 includes variables regarding 1st and 2nd S point curve values used estimating Runoff Curve Number 18 Interactive APEX i_APEX USERS GUIDE Figure 10 Parameters 1 Parameters Parameters5 Parameters 6 Parameters 7 Parameters 8 Parameters 2 Parameters 3 Parameters 4 1st S Point 2nd 5 Point 90 05 99 95 10 5 100 95 Coarse fragment roo
21. dat S Curve 22 2 Single none Not used iaparm dat S Curve 23 1 Single none ground cover standing live biomass 1 iaparm dat S Curve 23 2 Single none ground cover standing live biomass 2 iaparm dat Interactive APEX i APEX USERS GUIDE 51 Table A 14 continued Name ID Type Units Description APEX File S Curve 24 1 Single none Not used iaparm dat S Curve 24 2 Single none Not used iaparm dat S Curve 25 1 Single none Water content CN2 CN3 1 iaparm dat S Curve 25 2 Single none Water content CN2 CN3 2 iaparm dat Parml Single none Crop canopy Monteith PET iaparm dat Parm2 Single none Root growth soil strength iaparm dat Parm3 Single none Water stress harvest index iaparm dat Parm4 Single none Water storage N leaching iaparm dat Parm5 Single none Soil water lower limit iaparm dat Parm6 Single none Winter dormancy iaparm dat Parm7 Single none N fixation iaparm dat Parm8 Single none Soluble P adsorption coefficient iaparm dat Parm9 Single none Pest damage moisture iaparm dat Parm10 Single none Pest damage cover iaparm dat Parm11 Single none Seed germination iaparm dat Parm12 Single none Soil evaporation coefficient iaparm dat Parm13 Single none Wind erodibility coefficient iaparm dat Parm14 Single none Nitrate leaching ratio iaparm dat Parm15 Single none Runoff CN weighting factor iaparm dat Parm16 Single none CN retention parameter iap
22. fate model Agricultural Policy Environmental eXtender APEX Williams et al 2006 2008 Williams and Izaurralde 2006 Gassman et al 2010 I_APEX is programmed in C and performs automatic management of the input data execution of each APEX run and data storage of selected model outputs using a single Microsoft ACCESS database to manage both the input and output data required for APEX simulations The model provides a well organized easily understood interface with definitions and help assistance for most variables The greatest advantage of i_APEX is in its ability to perform multiple model runs over 100 000 runs in arun set in batch mode for each record selected in the Control Records Table This provides a tremendous advantage when attempting to model multiple scenario permutations for a single field or small watershed or in modeling thousands of agricultural fields and other land uses over a large area such as a river basin or region I APEX is being used by CEAP in a national effort to assess the effectiveness of agricultural conservation practices Kellogg et al 2011 2012a 2012b and 2012c Agricultural regions based on river basins of the United States are being modeled that simulate nutrient pesticide and sediment losses under conditions of agricultural practices based on national farmers surveys from 2003 2006 and 2011 2013 at over 40 000 selected National Resources Inventory NRI sample points The software has als
23. has not yet been established in these subareas In subarea 3 a routing reach has been defined since water moves through the subarea from the upper end of the subarea point at which water from the upstream subarea s enter the subarea to the subarea outlet e CHL gt RCHL In subarea 3 the distance from subarea outlet to the farthest point in the subarea is greater than the routing reach length through the subarea e WSA A negative watershed area WSA causes summation of subarea areas In Figure 19 subarea 2 is added to subarea 1 before being routed through 3 Figure 19 Example of Watershed and APEX Routing Method Denotes subarea boundary Denotes channel CHL Denotes reach channel RCHL Denotes watershed boundary Denotes subarea outlet point Denotes watershed outlet point From Steglich and Williams 2008 Subareas Floodplains and Filter Strips Floodplains and filter strips must be set up as a routing subarea that routes runoff from the upslope subarea to the floodplain or filter strip If the Subarea is a filter strip buffer the Filter Strip variable should be checked off in the Channel window located in the Subarea edit window Figure 18 The Filter Strip Flow Fraction in the Channel window must be input that determined the partitioning of flow through the filter strip or floodplain Typical values for the Filter Strip Flow Fraction are in the range from 0 87 to 0 98 Wang personal communic
24. mm Evapotransporation apex OUT 58 Interactive APEX i_APEX USERS GUIDE Table B 2 continued Name ID Type Units Description APEX File Qp Single kg ha Soluble phosphorus loss in apex OUT runoff Mnp Single kg ha Phosphorus mineralized apex OUT Avol Single kg ha NH3 nitrogen volatilization apex OUT Nitr Single kg ha Nitrification NH3 conversion to apex OUT NO3 Musl Single t ha Soil loss from water erosion apex OUT using modified MUSLE eguation Fnmn Single kg ha Fertilizer application of nitrate apex OUT Fnma Single kg ha Fertilizer application of apex OUT anhydrous ammonia Fno Single kg ha Fertilizer application of organic apex OUT nitrogen Fpo Single kg ha Fertilizer application of organic apex OUT phosphorus Fpl Single kg ha Fertilizer applied labile apex OUT phosphorus Soil Depth Single m apex OUT Soil Water Single none apex OUT Soil Bd Single t m 3 apex OUT Soil Sand Single apex OUT Soil Clay Single apex OUT Soil Ph Single none apex OUT Selected Variable 1 Single various apex OUT Selected Variable 2 Single various apex OUT Selected Variable 3 Single various apex OUT Selected Variable 4 Single various apex OUT Selected Variable 5 Single various apex OUT Selected Variable 6 Single various apex OUT Selected Variable 7 Single various apex OUT Selected Variable 8 Single various apex OUT Selected Variable 9 Single various apex OUT Selected Var
25. Appendix 1 Table 6 The model performs chemical and biochemical reactions that affect the nutrient bioavailability as well as nutrient runoff and infiltration Carbon dynamics and level of soil organic carbon are simulated throughout a model run Nitrification and denitrification dynamics are estimated by the model as well as nitrogen forms such as ammonium nitrate nitrite and labile and nonlabile forms of organic nitrogen Phosphorus chemistry is also determined by the model to estimate inorganic and organic forms utilized by the crop and leaving the field in runoff and percolation The user can manipulate nutrient chemistry and budgets by altering numerous variables found in Header 2 Figure 6 Header 3 Figure 7 Interactive APEX i_APEX USERS GUIDE 29 Header 4 Figure 8 and Header 5 Figure 9 as well as Parameter 1 Figure 10 Parameter 3 Figure 12 Parameter 4 Figure 13 Parameter 5 Figure 14 and Parameter 6 Figure 15 Runoff Curve Number greatly influences the partitioning of nitrogen and phosphorus between runoff soluble and associated with detritus and sediment losses and subsurface flow Pesticides Application of pesticides may result in losses in runoff percolation including subsurface lateral flow and absorbed to sediment particles Pesticides and their properties are found in the Pesticides ACCESS table Formatting for this table is shown in Appendix 1 Table 12 Pesticides may be applied by a
26. DE 49 Table A 13 Operations Name ID Type Units Description APEX File Name Text none til iatill dat Code Integer none ihc iatill dat Cost Single none colt iatill dat Mixing Efficiency Single None emx iatill dat Surface Random Roughness Single none IT iatill dat Tillage Depth Single none tld iatill dat Ridge Height Single none rht iatill dat Ridge Interval Single none rin iatill dat Furrow Dike Height Single none dkh iatill dat Furrow Dike Interval Single none dki iatill dat Harvest Pesticide Efficiency Ratio Single none he iatill dat Override Harvest Index Single none orhi iatill dat Fraction of Soil Compacted Single none frep iatill dat Fraction of Population Reduced Single none fpop iatill dat Pcd Single none ped iatill dat Pric Single none pric iatill dat Plst Single none plst iatill dat Hry Single none hry iatill dat Hrl Single none hrl iatill dat Pwr Single none pwr iatill dat Wdt Single none wdt iatill dat Spd Single none spd iatill dat Rel Single none rel iatill dat Rc2 Single none rc2 iatill dat XIb Single none xlb iatill dat Fcm Single none fem iatill dat Vri Single none vrl iatill dat Vr2 Single none vr2 iatill dat Efm Single none efm iatill dat Rti Single none rti iatill dat Table A 14 Miscellaneous Parameters for APEX2110 see Appendix C for APEX0604 and APEX0806 Name ID Type Units Description APEX File S Cur
27. EACH SOIL LAYER M Interactive APEX i_APEX USERS GUIDE 65 SCRP 21 N DISTANCE FACTOR IN SPATIAL RAINFALL GENERATOR X DISTANCE FROM STORM CENTER TO SUBAREA CENTROID KM SCRP 22 N GOVERNS PLANT WATER STRESS AS A FUNCTION OF SOIL WATER TENSION X GRAVIMETRIC OSMOTIC TENSION SCRP 23 N ESTIMATES PLANT GROUND COVER AS A FUNCTION OF LAI X TOTAL LAI OF ALL GROWING PLANTS SCRP 24 N ESTIMATES PLANT GROUND COVER AS A FUNCTION OF STANDING LIVE BIOMASS X STANDING LIVE BIOMASS T HA SCRP 25 N SIMULATES 02 CONTENT OF SOIL AS A FUNCTION OF C AND CLAY USED IN MICROBIAL PROCESSES OF RESIDUE DECAY X F C CLAY SCRP 30 N EXCEPTION TO NORMAL S CURVE PROCEDURE SETS SOIL WATER CONTENTS COINCIDING WITH CN2 AND CN3 X1 SOIL WATER CONTENT AS OF FIELD CAPACITY WILTING POINT X2 SOIL WATER CONTENT AS OF POROSITY FIELD CAPACITY PRMT 1 CROP CANOPY PET 1 2 FACTOR USED TO ADJUST CROP CANOPY RESISTANCE IN THE PENMAN MONTEITH PET EO PRMT 2 ROOT GROWTH SOIL STRENGTH 1 2 NORMALLY 1 15 lt PRMT 2 lt 1 2 SET TO 1 5 TO MINIMIZE SOIL STRENGTH CONSTRAINT ON ROOT GROWTH PRMT 2 gt 2 ELIMINATES ALL ROOT GROWTH STRESS PRMT 3 WATER STRESS HARVEST INDEX 0_1 SETS FRACTION OF GROWING SEASON WHEN WATER STRESS STARTS REDUCING HARVEST INDEX PRMT 4 WATER STORAGE N LEACHING 0 1 FRACTION OF SOIL POROSITY THAT INTERACTS WITH PERCOLATING WATER AS N LEACHING OCCURS PRMT 5 SOIL WATER LOWE
28. ESIDUE DECAY RATE 5 15 PRMT 53 COEF IN OXYGEN EQ USED IN MODIFYING MICROBIAL ACTIVITY WITH SOIL DEPTH 0 8 0 95 PRMT 54 N ENRICHMENT RATIO COEF FOR ROUTING 0 3 0 9 GLEAMS EQ ERTO MIN 3 5 PRMT 54 CIN PRMT 55 PRMT 55 N ENRICHMENT RATIO EXP FOR ROUTING 1 3 GLEAMS EQ PRMT 56 FRACTION DESTROYED BY BURN OPERATION 5 1 PRMT 57 P ENRICHMENT RATIO COEF FOR ROUTING 05_ 2 GLEAMS EQ ERTP PRMT 57 CY 1 E 4 PRMT 58 PRMT 58 P ENRICHMENT RATIO EXP FOR ROUTING 0 3 0 9 GLEAMS EO Interactive APEX i APEX USERS GUIDE 69 PRMT 59 P UPWARD MOVEMENT BY EVAPORATION COEF 1 20 PRMT 60 MAXIMUM NUMBER OF DAYS A PASTURE IS GRAZED BEFORE ROTATION 1 365 PRMT 61 SOIL WATER UPWARD FLOW LIMIT 0 05 0 95 LIMITS WATER TENSION RATIO USED TO MOVE WATER FROM A LOWER LAYER TO THE ONE ABOVE IT X1 XX MIN PRMT 61 T1 T2 T1 PRMT 62 MANURE EROSION EQ COEF 0 1 0 5 LARGER VALUES INCREASE MANURE EROSION PRMT 63 N ENRICHMENT RATIO FOR DELIVERY TO SWAT 0 8_1 2 ENRICHMENT RATIO FOR APPLICATION TO 8 DIGIT SEDIMENT YIELD SUPPLIED TO SWAT PRMT 64 DUST DISTRIBUTION COEF 0 5_ 1 5 AFFECTS DUST DISTRIBUTION AS A FUNCTION OF DOWNWIND TRAVEL TIME PRMT 65 RUSLE 2 TRANSPORT CAPACITY PARAMETER 0 001_0 1 REGULATES DEPOSITION AS A FUNCTION OF PARTICLE SIZE AND FLOW RATE PRMT 66 RUSLE 2 THRESHOLD TRANSPORT CAPACITY COEFFICIENT 1 0 10 0 ADJUSTS THRESHOLD FLOW RATE SLOPE STEEPNESS PRMT 67 DUST
29. EXPRESSES THE EFFECT OF SOIL COURSE FRAGMENT CONTENT ON PLANT ROOT GROWTH RESTRICTION X COURSE FRAGMENT N 1 2 SCRP 2 N GOVERNS SOIL EVAPORATION AS A FUNCTION OF SOIL DEPTH X SOIL DEPTH MM SCRP 3 N DRIVES HARVEST INDEX DEVELOPMENT AS A FUNCTION OF CROP MATURITY X OF GROWING SEASON SCRP 4 N NRCS RUNOFF CURVE NUMBER SOIL WATER RELATIONSHIP EXCEPTION TO NORMAL S CURVE PROCEDURE SOIL WATER FRACTIONS TAKEN FROM SCRP 25 N TO MATCH WITH CN2 AND CN3 AVERAGE AND WET CONDITION RUNOFF CURVE NUMBERS SCRP 5 N ESTIMATES SOIL COVER FACTOR USED IN SIMULATING SOIL TEMPERATURE X TOTAL ABOVE GROUND PLANT MATERIAL DEAD AND LIVE SCRP 6 N SETTLES AFTER TILLAGE SOIL BULK DENSITY TO NORMAL VALUE AS A FUNCTION OF RAINFALL AMOUNT SOIL TEXTURE AND SOIL DEPTH X RAINFALL MM ADJUSTED FOR SOIL TEXTURE AND DEPTH 64 Interactive APEX i APEX USERS GUIDE SCRP 7 N DETERMINES THE ROOT GROWTH AERATION STRESS FACTOR AS A FUNCTION OF SOIL WATER CONTENT AND THE CRITICAL AERATION FACTOR FOR THE CROP X SOIL WATER CRITICAL AERATION FACTOR SCRP 8 N DETERMINES THE PLANT STRESS CAUSED BY N OR P DEFICIENCY X OF OPTIMAL N OR P CONTENT PRESENT IN PLANT SCRP 9 N CALCULATES THE PEST DAMAGE FACTOR AS A FUNCTION OF TEMPERATURE CONSIDERING THRESHOLDS FOR 30 DAY RAINFALL AND ABOVE GROUND PLANT MATERIAL X SUM OF DAILY MINIMUM TEMPERATURE WITH RAINFALL ADJUSTMENT SCRP 10 N CALCULATES THE EFFECT OF WATER STRESS
30. Integer days iri iasub dat Interval Minimum Auto Fertilizer Long Integer days ifa iasub dat Interval Liming Code Long Integer none lm nnnn ops Furrow Dike Code Long Integer none ifd nnnn ops Drainage Code Long Integer none idr iasub dat Lagoon Fertigation Code Integer none idfl iasub dat Feeding Area Manure Code Integer none idf2 iasub dat Daily Manure Application Code Integer none idf3 iasub dat Auto Commercial N Code Integer none idf4 iasub dat Auto Solid Manure Code Integer none idf5 iasub dat Irrigation Trigger Single none bir iasub dat Irrigation Runoff Ratio Single Variable efi iasub dat Maximum Annual Irrigation Single mm vimx iasub dat Volume Minimum Single Irrigation Single mm armn iasub dat Volume Maximum Single Irrigation Single mm armx iasub dat Volume Auto Fertilizer Trigger Single Variable bft iasub dat Fertilizer Auto Rate Depth Single Variable fnp4 iasub dat Maximum Annual N Single kg ha fmx iasub dat Drainage End Stress Single days drt iasub dat Interactive APEX i APEX USERS GUIDE 43 Table A 4 continued Name ID Type Units Description APEX File Furrow Dike Safety Factor Single none fdsf iasub dat Conservation Practice Factor Single none pec iasub dat Lagoon Control Fraction Single none dalg iasub dat Lagoon Volume Ratio Single none vglm iasub dat Lagoon Input from Wash Single m 3 cow dat COWW iasub dat Lagoon T
31. Interactive APEX i_APEX USER S GUIDE USING APEX2110 and APEX0806 March 2014 Technical Report 14 TR 50 by Mark Siemers Stephen Plotkin Phil Gassman Center for Agricultural and Rural Development lowa State University Ames lowa 50011 1070 www card iastate edu Center for Agricultural and Rural Development lowa State University Ames lowa email marks iastate edu or pwgassma iastate edu University of Massachusetts Extension USDA Natural Resources Conservation Service Amherst MA lowa State University does not discriminate on the basis of race color age ethnicity religion national origin pregnancy sexual orientation gender identity genetic information sex marital status disability or status as a U S veteran Inquiries can be directed to the Interim Assistant Director of Equal Opportunity and Compliance 3280 Beardshear Hall 515 294 7612 Contents Eist OF BIGUF2S ii Ad ii Eist OF Tabl ES rs kamina SA RSE EGS ii Interactive APEX 1 APEX sci 02130048 5bH8p it ae rino a sh EIB iia 111 TNT O GU CHI ON a ad did sae eit 1 ToAPEX Methods cnt iii EA aaa damas diodes 2 ACCESS Database Links oooooccccnnnoccononancnononancnnononnnnonnnonononnnnnononnnnnanonnnn nono ono nono onnn nan ronnnnaronnnos 5 Getting Started i APEX Graphical User Interface cc cccccsccsseceseceneceeeceseeeseeeseecseecseesseenseeeaeens 7 Mena aaa ta iaa iaa aa rica 8 DO a aiii 10 CONCILIO enirere di AA A AAA LA Ride 11
32. MUSLE with input parameters see BUS 1 RUSLE Revised Universal Soil Loss Equation and RUSLE2 Modified RUSLE Interactive APEX i_APEX USERS GUIDE 27 Hydrology Components of APEX that most affect hydrology include simulation of Runoff percolation and subsurface flow Irrigation Evapotranspiration Runoff There are four methods that can be used to model runoff and percolation by selecting the Runoff Estimation Methodology options Header 2 Figure 6 Curve number estimate of Q Runoff Curve Number estimator select either Stochastic or Rigid Green and Ampt Q Exponential rainfall simulation Peak rainfall rate simulated Green and Ampt Q Exponential rainfall Input peak Peak rain input Green and Ampt 0 Uniform rainfall Uniformly distributed peak rainfall input Using sensitivity analysis of APEX hydrologic variables Wang et al 2006 determined that the NRCS Runoff Curve Number index coefficient CNIC and CN2 variables were particularly influential in the effects of runoff and percolation Curve number may be input manually in field operations or the model can automatically determine the values over the simulation period as crops cover crops tillage and hydrologic soil conditions change Manual input of CN2 will remain unchanged throughout the model run unless a new value is input in a subsequent field operation Irrigation Two irrigation modes are available Automatic Specifications of auto
33. R LIMIT 0 1 LOWER LIMIT OF WATER CONTENT IN THE TOP 0 5 M SOIL DEPTH EXPRESSED AS A FRACTION OF THE WILTING POINT WATER CONTENT PRMT 6 WINTER DORMANCY H 0_1 CAUSES DORMANCY IN WINTER GROWN CROPS GROWTH DOES NOT OCCUR WHEN DAY LENGTH IS LESS THAN ANNUAL MINIMUM DAY LENGTH PRMT 6 PRMT 7 NFIXATION 0 1 AT 1 FIXATION IS LIMITED BY SOIL WATER OR NITRATE CONTENT OR BY CROP GROWTH STAGE At 0 FIXATION MEETS CROP N UPTAKE DEMAND A COMBINATION OF THE 2 FIXATION ESTIMATES IS OBTAINED BY SETTING 0 lt PRMT 7 lt 1 PRMT 8 SOLUBLE P ADSORPTION COEF 1 M23 D 10_20 P CONCENTRATION IN SEDIMENT DIVIDED BY THAT OF THE WATER 66 Interactive APEX i APEX USERS GUIDE PRMT 9 PEST DAMAGE MOISTURE THRESHOLD MM 25_150 PREVIOUS 30 DAY RAINFALL MINUS RUNOFF PRMT 10 PEST DAMAGE COVER THRESHOLD T HA 1_ 10 CROP RESIDUE ABOVE GROUND BIOMASS PRMT 11 MOISTURE REQUIRED FOR SEED GERMINATION MM 10 30 SOIL WATER STORED MINUS WILTING POINT STORAGE IN THE PLOW DEPTH PMX PRMT 43 PRMT 12 SOIL EVAPORATION COEF 1 5 2 5 GOVERNS RATE OF SOIL EVAPORATION FROM TOP 0 2 M OF SOIL PRMT 13 WIND ERODIBILITY COEF 0_3 ADJUSTS WIND SOIL ERODIBILITY FACTOR DOWNWARD AS LOOSE MATERIAL IS ERODED PRMT 14 NITRATE LEACHING RATIO 0 1_1 NITRATE CONCENTRATION IN SURFACE RUNOFF TO NITRATE CONCENTRATION IN PERCOLATE PRMT 15 RUNOFF CN RESIDUE ADJUSTMENT PARAMETER 0 0 0 3 INCREASES RUNOFF FOR RSD lt 1 0 T HA DECREASES FO
34. R RSD gt 1 0 PRMT 16 EXPANDS CN RETENTION PARAMETER 1 0_ 1 5 VALUES gt 1 0 EXPAND CN RETENTION PARAMETER AND REDUCE RUNOFF PRMT 17 SOIL EVAPORATION PLANT COVER FACTOR 0 0 0 5 REDUCES EFFECT OF PLANT COVER AS RELATED TO LAI IN REGULATING SOIL EVAPORATION PRMT 18 SEDIMENT ROUTING EXPONENT 1 1 5 EXPONENT OF WATER VELOCITY FUNCTION FOR ESTIMATING POTENTIAL SEDIMENT CONCENTRATION PRMT 19 SEDIMENT ROUTING COEF T M23 0 01_0 05 POTENTIAL SEDIMENT CONC WHEN FLOW VELOCITY 1 M S PRMT 20 RUNOFF CURVE NUMBER INITIAL ABSTRACTION 0 05_ 0 4 PRMT 21 SOLUBLE C ADSORPTION COEF 1 M 3 T 10_20 C CONCENTRATION IN SEDIMENT DIVIDED BY THAT IN WATER PRMT 22 REDUCES NRCS RUNOFF CN RETENTION PARM FOR FROZEN SOIL FRACTION OF S FROZEN SOIL 0 05 0 5 PRMT 23 HARGREAVES PET EQ COEF 0 0023 0 0032 ORIGINAL VALUE 0 0023 PRMT 24 PESTICIDE LEACHING RATIO 0 1_1 PESTICIDE CONCENTRATION IN SURFACE RUNOFF TO PESTICIDE CONCENTRATION IN PERCOLATE PRMT 25 RAINFALL INTENSITY ADJUSTMENT FOR CN 0 0 2 0 SCN SCN EXP PRMT 25 2 AL5 Interactive APEX i APEX USERS GUIDE 67 PRMT 26 FRACTION OF MATURITY AT SPRING GROWTH INITIATION 0_ 1 ALLOWS FALL GROWING CROPS TO RESET HEAT UNIT INDEX TO A VALUE GREATER THAN 0 WHEN PASSING THROUGH THE MINIMUM TEMP MONTH PRMT 27 CEC EFFECT ON NITRIFICATION amp VOLATILIZATION 0 1 SETS LOWER LIMIT OF CEC CORRECTION FACTOR IN NIT VOL FUNCTION AT 0 CEC SHOULD PRE
35. RICE PADDYS BY SETTING SECOND SOIL LAYER SATURATED CONDUCTIVITY TO A LOW VALUE PRMT 40 GROUNDWATER STORAGE THRESHOLD 001 1 FRACTION OF GROUNDWATER STORAGE THAT INITIATES RETURN FLOW 68 Interactive APEX i_APEX USERS GUIDE PRMT 41 PLANT ROOT TEMPERATURE STRESS EXP 1 2 EXP OF RATIO OF SOIL LAYER TEMP TO AVE OF PLANT OPTIMAL AND BASE TEMPS PRMT 42 SCS CURVE NUMBER INDEX COEF 3_ 2 5 REGULATES THE EFFECT OF PET IN DRIVING THE SCS CURVE NUMBER RETENTION PARAMETER PRMT 43 PLOW LAYER DEPTH M USED TO TRACK SOLUBLE P CONCENTRATION OR WEIGHT ORGANIC C AND SOIL WATER CONTENT PRMT 44 UPPER LIMIT OF CURVE NUMBER RETENTION PARAMETER S 1 _ 2 SUL PRMT 44 S1 ALLOWS CN TO GO BELOW CN1 PRMT 45 SEDIMENT ROUTING TRAVEL TIME COEF 5_ 10 BRINGS INFLOW SEDIMENT CONC TO TRANSPORT CAPACITY CONC AS A FUNCTION OF TRAVEL TIME AND MEAN PARTICLE SIZE PRMT 46 RUSLE C FACTOR COEF 5 1 5 COEF IN EXPONENTIAL RESIDUE FUNCTION IN RESIDUE FACTOR PRMT 47 RUSLE C FACTOR COEF 5 1 5 COEF IN EXPONENTIAL CROP HEIGHT FUNCTION IN BIOMASS FACTOR PRMT 48 ADJUSTS CLIMATIC STRESS FACTOR AAP AAT PRMT 48 50 80 SET TO 0 0 GIVES CLF 1 PRMT 49 MAXIMUM RAINFALL INTERCEPTION BY PLANT CANOPY MM 0 0 15 0 PRMT 50 RAINFALL INTERCEPTION COEF 05_ 3 PRMT 51 WATER STORAGE CAPACITY OF LITTER RESIDUE COEF 1 9 FRACTION OF LITTER WEIGHT PRMT 52 EXPONENTIAL COEF IN EQ EXPRESSING TILLAGE EFFECT ON R
36. SERS GUIDE 23 Figure 15 Parameters 6 Parameters Parameters 1 Parameters 2 Parameters 3 Parameters 4 Parameters 5 E Parameters 7 Parameters 8 o o ol wE Soil water tension weighting Groundwater N ol Manure erosion eq coef Furrow irrigation erosion coef Pesticide loss coef Furrow irrigation sediment Dust Distribution coef SWAT N enrichment ratio SWAT P enrichment ratio Runoff delay pest applicate Soil water delay tillage Standing dead fall rate Dust distribution dispersion exp Puddling saturated Manure erosion exponent Technology Adust micrbial activity function CN rainfall intensity Microbial decay rate coef Lateral hydraulic 0 0001 Manure erosion coef P flow labile active pools 0 0001 Wolitilization nitrofication coef P flow active stable min pool 1 CUE TRUE TE B 7 e Hydrograph developement parm Parameters 7 Window See Appendix 1 Table 14 for APEX2110 parameters Appendix 3 for APEX0806 Parameters 7 in Figure 16 includes parameters 86 to 96 regarding nitrogen upward movement from evapotranspiration water table including return flow channel and floodplain evaporation runoff volume adjustment cost parameters 24 Interactive APEX i_APEX USERS GUIDE Figure 16 Parameters 7 aramete Parameters 1 Parameters 2 Parameters 3 Parameters 4 Parameters 5 Parameters 6 Parameters 7 Parameters 8 Parm 86 Parm 87 Parm 88 Parm 89 Parm 90 mM o
37. VENT NIT VOL PROCESS AT 1 CEC HAS NO EFFECT ON NIT VOL PRMT 28 UPPER LIMIT OF N FIXATION KG HA 0 1 20 PRMT 29 BIOLOGICAL MIXING EFFICIENCY 0 1 0 5 SIMULATES MIXING IN TOP SOIL BY EARTH WORMS ETC PRMT 31 SETS DEPTH PRMT 30 SOLUBLE P RUNOFF EXPONENT 1_ 1 5 PROVIDES NONLINEAR EFFECT FOR SOLUBLE P RUNOFF EQ PRMT 31 MAXIMUM DEPTH FOR BIOLOGICAL MIXING M 0 1 0 3 PRMT 32 ORGANIC P LOSS EXPONENT 1 1 2 PROVIDES NONLINEAR EFFECT FOR ORGANIC P LOSS EO PRMT 33 COEFFICIENT IN MUST EO 2 0 3 0 ORIGINAL VALUE 2 5 PRMT 34 HARGREAVES PET EQ EXP 0 5 0 6 ORIGINAL VALUE 0 5 MODIFIED TO 0 6 TO INCREASE PET PRMT 35 DENITRIFICATION SOIL WATER THRESHOLD 9 1 1 FRACTION OF FIELD CAPACITY SOIL WATER STORAGE TO TRIGGER DENITRIFICATION PRMT 36 UPPER LIMIT OF DAILY DENITRIFICATION RATE 0 0001 0 5 MAXIMUM FRACTION OF NO3 IN A SOIL LAYER SUBJECT TO DENITRIFICATION PRMT 37 EXPONENT IN DELIVERY RATIO FOR SWAT OUTPUT 0 1_ 0 6 TRANSFORMS APEX SMALL WATERSHED SEDIMENT YIELD TO 8 DIGIT BASIN SEDIMENT YIELD FOR SWAT INPUT NORMALLY 0 5 LOWER VALUES INCREASE SEDIMENT YIELD TO SWAT PRMT 38 WATER STRESS WEIGHTING COEF 0 1 AT 0 PLANT WATER STRESS IS STRICTLY A FUNCTION OF SOIL WATER CONTENT AT 1 PLANT WATER STRESS IS STRICTLY A FUNCTION OF ACTUAL ET DIVIDED BY POTENTIAL ET O lt PRMT 38 lt 1 CONSIDERS BOTH APPROACHES PRMT 39 PUDDLING SATURATED CONDUCTIVITY MM H 0 00001 0 1 SIMULATES PUDDLING IN
38. anarayanan et al 1997 Gassman et al 2002 and Williams et al 2006 APEX has been used as a Best Management Practice BMP model by simulating land management scenarios Borah et al 2006 The model has been calibrated and validated for hydrology and nutrient and sediment losses Wang et al 2006 Ramanarayanan et al 1998 and Wang et al 2008 and for pesticide losses Mudgal et al 2010 Plotkin et al 2013 This user manual provides explanations for i_ APEX interface structure navigating through the i_APEX screens input and output tables and instruction on how to set up scenarios and perform model Runs Guidance is provided on design and construction of scenarios and sample set ups to perform desired simulations of nutrient pesticide and sediment movement through contiguous fields channels that drain the fields field run on run off and reservoir input output A thorough explanation of APEX concepts and equations is provided by Williams et al 2008 and will only be addressed in this manual in a general manner to explain i APEX methods for employing these concepts Comprehensive variable definitions can be found in the APEX user s manual Steglich and Williams 2008 Definitions are also provided for most variables at the bottom of each i APEX interface screen I APEX Methods I APEX ACCESS tables contain the input data that APEX reads and uses to build a complete set of APEX input files The program executes APEX reads the
39. and ext is the extension cont sub ops parm and out respectively Save SWAT files saves apex SWAT output files for all runs as swnnnnnn swat where nnnnnn is the control record number Create Yearly table fills Yearly table for each APEX run Create Watershed table fills Watershed table for each APEX run Create Residue Output table fills Residue Output table Pre Check All Records checks all control records for data errors Pre Check This Record checks the current control record for data errors 7 Record New creates new dummy control record Delete deletes current control record First makes the first control record the current control record Previous moves the current control record up one record Next makes the next control record the current control record Last makes the last control record the current control record Go To goes to specified record number Search finds specified record ID 8 Help Help Contents not yet implemented Help Search not yet implemented About i_APEX Interactive APEX i_APEX USERS GUIDE 9 Toolbar S 1 Print tool inoperative i 2 Select beginning record 4 3 Select previous record 4 Select next record bl 5 Select last record v 6 Create new record b 7 Go to specified record Wis Search for record 4 Edit database Fertilizer table 10 Edit database Pesticide table Man Edit database Crop table E Edit database Oper
40. arameter fields change their definition depending on the type of the field operation indicated by the Type field Figure 20 The Type field links to the entries in the ACCESS Operations table which contains the operation name among other variables A set of field operations make up a crop rotation for each subarea within arun The field operations within the rotation are ordered by date with the Year Month and Day To edit an operation click on the field operation in the list box and select Change Operation To add a field operation select Add Operation and to delete a field operation click on the field operation in the list box and select Delete Operation Adding or editing a field operation can be performed using the Subarea Field Operation Addition Edit Change window Figure 20 To edit an existing field operation record click directly on the record to be changed in the Field operations window The operation shown in Figure 20 is for planting The field operation name will appear in the upper left section of the window after identifying the Type ID number from the ACCESS Field Operations table identifying Year Month and DAY selecting OK which saves a field operation and exits the window followed by clicking on the new field operation to re invoke the window Other variables pertinent to the particular field operation may then be input Selecting Cancel in the Subarea Edit Window cancels all previous field operation edits I
41. arm dat Parm17 Single none Soil evaporation plant cover iaparm dat Parm18 Single none Sediment routing exponent iaparm dat Parm19 Single none Sediment routing coefficient iaparm dat Parm20 Single none Runoff curve number initial iaparm dat Parm21 Single none Soluble C adsorption iaparm dat Parm22 Single none Not used iaparm dat Parm23 Single none Hargreaves PET equation coefficient iaparm dat Parm24 Single none Pesticide leaching ratio iaparm dat Parm25 Single none Not used iaparm dat Parm26 Single none Maturity at spring growth iaparm dat Parm27 Single none CEC effect on nitrification iaparm dat Parm28 Single none Not used iaparm dat Parm29 Single none Biological mixing efficiency iaparm dat Parm30 Single none Soluble P runoff exponent iaparm dat Parm31 Single none Maximum depth of mixing iaparm dat Parm32 Single none Organic P loss exponent iaparm dat Parm33 Single none Not used iaparm dat Parm34 Single none Hargreaves PET equation exponent iaparm dat Parm35 Single none Denitrification soil water iaparm dat Parm36 Single none Denitrification rate constant iaparm dat Parm37 Single none Not used iaparm dat 52 Interactive APEX i_APEX USERS GUIDE Table A 14 continued Name ID Type Units Description APEX File Parm38 Single none Water stress weighting iaparm dat Parm39 Single none iaparm dat Parm40 Single none Ground water storage
42. ased August 30 2012 Conservation Effects Assessment Project USDA Natural Resources Conservation Service Washington D C Website http www nrcs usda gov technical nri ceap Monteith J L 1965 Evaporation and environment Symp Soc Exp Biol 19 205 234 Mudgal A C Baffaut S H Anderson E J Sadler and A L Thompson 2010 APEX model assessment of variable landscapes on runoff and dissolved herbicides Trans ASABE 53 4 1047 1058 Penman H L 1948 Natural evaporation from open bare soil and grass Proc Soc London Ser A193 120 145 Plotkin S X Wang T L Potter D D Bosch J R Williams E S Hesketh and J K Bagdon 2013 APEX Calibration and Validation of Water and Herbicide Transport under Southern Atlantic Coastal Plain USA Conditions Trans ASABE 56 1 43 60 Priestley C H B and R J Taylor 1972 On the assessment of surface heat flux and evaporation using large scale parameters Mon Weather Rev 100 81 92 Interactive APEX i APEX USERS GUIDE 37 Ramanarayanan Tharacad S M V Padmanabhan G N Gajanan Jimmy Williams 1998 Comparison of simulated and observed runoff and soil loss on three small United States watersheds NATO ASI Series 1 55 76 88 Ramanarayanan T S J R Williams W A Dugas L M Hauck and A M S McFarland 1997 Using APEX to identify alternative practices for animal waste management Presented at the ASAE International Meeting Minneapol
43. ation January 2013 Other physical values that characterize the filter strip or floodplain are located in the Channel window The Floodplain Saturated Conductivity and Floodplain Width in Header 32 Interactive APEX i_APEX USERS GUIDE 4 Figure 8 can be adjusted to determine the extent of filtration that occurs in the filter strip or floodplain Subarea Field Operations The Field operations edit window is located in the lower right section of the Subarea window This area has three buttons Change Operation Add Operation and Delete Operation and a list box below of the operations Field operations are the drivers of APEX modeling that includes all aspects of field management e Conservation Practices Tillage Planting Fertilization Chemical Applications e g liming and ammonium Pesticide application Irrigation Harvest Killing the Crop Cover Crop All subareas where a crop is grown must have a planting record a harvest record and a kill record to end the crop A crop will continue to grow even after harvest mowing and being turned under if a Kill record is not used to end the crop Pasture land of course does need to be killed A field operation record consists of sixteen variable fields nine integer fields followed by seven real fields called parameter fields The first eight integer fields include ID Subarea Id Year Month Day Type Tractor and Crop Id The last integer field and the seven p
44. ations table 13 Inoperative Dis Run current record is Run all records 10 Interactive APEX i_APEX USERS GUIDE Configuration The configuration window is used to set the i_ APEX executable location on your computer choose the version of APEX to run select output variables and files and indicate the number of years of output to be saved Figure 4 These settings are automatically saved when exiting i APEX The top line indicates the location and name of the APEX executable Located to the right is the change button that allows the user to browse to another APEX executable The executable name must be apex2110v3 exe or apex0806 exe as applicable to match the name internal to the i APEX code By default the directory containing the APEX executable becomes the run directory for i APEX and APEX Placing a check in the Prebuild Control Record List check box tells i APEX to fill the control record list at the right of the interface based on the Control Record table in the database Otherwise the control record list is filled as each control record is run A check beside Prebuild soil list will tell i_ APEX to list soils by name when clicking the soil select button in the Subareas Window The next line selects the version of APEX to run Each version of APEX requires a different set of parameters in the database parameter table When the version is changed the Parameter table must also be changed Output variables are located in
45. bles The USDA Natural Resources Conservation Service has sampling data for many of the soil inputs Soil water holding capacity parameters required by the model including bulk density field capacity wilting point and saturated conductivity When measured field capacity and wilting point are unavailable the values may be estimated from bulk density texture organic carbon content and soil fragments using soil equations calculated by the model and designated in of the Control Records Table Appendix 1 Table 1 for the Field Capacity Method variable ISW 0 Field capacity wilting point estimated using the Rawls method dynamic 1 Field capacity wilting point inputted using Rawls method dynamic 2 Field capacity wilting point estimated using Rawls method static 3 Field capacity wilting pointed inputted static Alternatively these soil parameters and saturated conductivity may be calculated external to the model e g Saxton and Rawls 2006 and input into the soils tables by the user Erosion Sediment APEX allows six different methods that can be used to estimate soil erosion depending upon availability of field soil crop and rainfall intensity information Graphical user interface Figure 3 as defined by Steglich and Williams 2011 These include MUST Modified MUSLE theoretical based equation AOF Onstad Foster USLE Universal Soil loss Equation MUSS Small Watershed MUSLE MUSLE Modified USLE MUSI Modified
46. ccceseceseceseceseeeeeeeseeeeeeesseceseeeseceaecesecsseeeeeeseeeseeeenseeeaes 62 Table B 6 Watershed Output cccccccccecsessecesecesecsseceneceeeeseeeeeseesseeeseecseecssecsaecnseceseceseseeeeseeeseeeeaes 63 Interactive APEX i_APEX Program Objective To provide a tool for managing large numbers of APEX runs handling data input and output Program Components e ACCESS Database Contains input tables used by i_APEX to construct APEX runs and output tables to organize APEX output e Graphical User Interface Allows for single runs and ranges of runs and permits editing of input data as well as selection of output variables and output files Program Operation e Fill the ACCESS database with the necessary data Execute I APEX and bring up the interface e Select output variables and output files using the interface e Make any necessary edits in the interface e Select and execute the runs using the interface e Examine the relevant output tables in the ACCESS database Output Capabilities e General output by APEX run and subarea e General output by run subarea and year e Output to the SWAT model e Pesticide output by year e Yield output by year e Organic carbon and nitrogen output by year and soil layer e Watershed output by year and month Users e CEAP National Assessment iii iv Introduction The interactive APEX 1 APEX is a user friendly interface for the physical process and environmental
47. cle crop winter dormancy root growth soil strength crop uptake of nitrogen and phosphorus pest effects on crops seed germination moisture wind erodibility coefficient runoff curve number factors soil water lower limit water stress harvest index sediment routing exponent coefficient 20 Interactive APEX i_APEX USERS GUIDE Figure 12 Parameters 3 Parameters Parameters 5 Parameters 6 Parameters 7 Parameters 8 Parameters 1 Parameters 2 E Parameters 4 o o Crop canopy Monteith PET 2 Seed germimation moisture Root growth soil strength 2 Soil evaporation coef Water stress havest index 0 5 Wind erodibility coef Water storage N leaching 05 Nitrate leaching ratio Soil water lower limit 05 Runoff CN weighting factor Winter dormancy 05 CN retention parameter N fixation 0 9 Soil evaporation plant cover Soluble P adsorbtion coef f 5 Sediment routing exponent Pest damage moiture 20 Sediment routing coef Pest damage cover 20 Runoff curve number initial 1 HE Cancel Help Parameters 4 Window See Appendix 1 Table 14 for APEX2110 parameters Appendix 3 for APEX0806 Parameters 4 in Figure 13 includes variables regarding crop carbon uptake crop growth variables water stress root decay rate frozen soil effect on runoff curve number Hargreaves coefficient exponent partitioning of pesticides between runoff and leaching mineralization effects biological mixing phosphorus and nitrogen dy
48. d Operation Addition Edit wrwenrennseenreenrenrerreenei 34 List of Tables Table 1 ACCESS Database Input Tables rmrenrenrerereeeeenerereennnennne enne eeni 3 Table 2 ACCESS Database Output Tables ceecccecscesseeeseesseeeseeeeeesaecaecnsecnaeesseesereeeeeseneesss 11 Table A 1 Control RECOS e i aa a a aaa a a e N E EN Sae 39 Table AZ 658 5511077 Srina ie a a A ST ia 41 Table Ay 3 UDCA a as 42 Table A4 MM ideada diia 43 Table AS Field Operations caia dd a titanio 44 Table AG Ol AA TT a 45 Tables ALTE Soil ETS A A KUD a ed A da A 46 Table Aca ca 46 Table A 9 Weather by Month 47 Table ACLOSCTOPS ui a 47 Table A LI Fertilizer eo a di A da chart 49 Table A LD Pet dr a a e oie 49 Table A 13 Operations cccccecsseessecseesseceseceseceseceseceseceeeeseneeeseceseeeseecsaecsaecsaecseceseeeseeeeseseeeeeeeeags 50 Table A 14 Miscellaneous Parameters for APEX2110 mienreenseenaennenneenneeneneneneneni 50 Table A 15 Selected Variables iman 54 Table B 1 Average Output a a r ra A A Ea E a aE S a TAE Ea ERTA rini 55 Table B2 Y early Q tput nienn A A A A liide k e Jiale 58 Table B 3 Crop Yield Output ccccccccssccssecesecesecseeceeeeseeeseeeeeseeeseeeseecseecsaecaeenseceseceeeseeeseeeseeeeaes 6l Table B 4 Monthly SWAT Output cccecccccccesecesecseeceeeeeeeeeeseceseeeseecseecssecsseceseceseseseeneeeseeeseneeses 62 Table B 5 Organic C and N Output cccceccc
49. e Gmn Single kg ha Gross nitrogen apex OUT mineralized Dn Single kg ha Nitrogen loss by apex OUT denitification Dprk Single mm Deep percolation apex OUT Nfix Single kg ha Nitrogen fixed by apex OUT leguminous crops Et Single mm Evapotransporation apex OUT Qp Single kg ha Soluble phosphorus loss apex OUT in runoff Mnp Single kg ha Phosphorus mineralized apex OUT Avol Single kg ha NH3 nitrogen apex OUT volatilization Nitr Single kg ha Nitrification NH3 apex OUT conversion to NO3 Musl Single t ha Soil loss from water apex OUT erosion using modified MUSLE eguation Fnmn Single kg ha Fertilizer application of apex OUT nitrate Interactive APEX i_APEX USERS GUIDE 55 Table B 1 continued Name ID Type Units Description APEX File Fnma Single kg ha Fertilizer application of apex OUT anhydrous ammonia Fno Single kg ha Fertilizer application of apex OUT organic nitrogen Fpo Single kg ha Fertilizer application of apex OUT organic phosphorus Fpl Single kg ha Fertilizer applied labile apex OUT phosphorus Soil Depth Single m apex OUT Soil Water Single none apex OUT Soil Bd Single t m 3 apex OUT Soil Sand Single apex OUT Soil Clay Single apex OUT Soil Ph Single none apex OUT Selected Variable 1 Single various apex OUT Selected Variable 2 Single various apex OUT Selected Variable 3 Single various apex OUT Selected Variable
50. e Operation Add Operation Delete Operation Miscellaneous Channel Reservoir Lagoon Grazing Routing Reach Auto Fertilization Auto Irrigation Table 1 ACCESS Database Input Tables Table Name Corresponding Apex Input Files Table Contents Table Structure Control Records apexcont dat Data general to the run One record per execution of iasite dat APEX Crops iacrop dat Crop parameters One record per crop Fertilizer iafert dat Fertilizer parameters One record per fertilizer Field Operations nnnn ops Operation schedule data One record per operation Livestock iasite dat Herd data One record for each of ten possible herds per run Management iasub dat Management data One record per subarea Operations iatill dat Tillage operation parameters One record per operation Parameters iaparm dat Coefficients internal to APEX One record per control record Pesticide iapest dat pesticide parameters One record per pesticide Point Source iasub dat Point source pollution file One record per file name names Selected Variables iaprnt dat User selected output variables One record per variable Soil Layers nnnn sol Soil layer data One record per layer per soil Soils nnnn sol General soil data One record per soil Subareas iasub dat General subarea data One record per subarea nnnn ops Weather iaweath dat Weather station data One record per weather station Weather by Month iaw
51. e bus 3 apexcont dat MUSI Parameter 4 Single none bus 4 apexcont dat Manure Rate for P Uptake Single none upr iasite dat Manure Rate for N Uptake Single none unr iasite dat Channel Cap Flow Rate Single none qg apexcont dat Exponent in Flow Rate Eq Single none qcf apexcont dat Ave Upland Slope Single none chs0 apexcont dat Channel Bottom Width Single none bwd apexcont dat Floodplain Width Single none few apexcont dat Floodplain Saturated Conductivity Single none fpsc apexcont dat Maximum Groundwater Storage Single none gws0 apexcont dat Return Flow Days Single none rft0 apexcont dat Return Flow Ratio Single none rfp0 apexcont dat Saturated Conductivity Adjustment Single none sat0 apexcont dat Field Width Single none fw apexcont dat Field Length Single none fl apexcont dat Field Angle Single none ang apexcont dat Power Parameter Single none uxp apexcont dat Soil Particle Diameter Single none diam apexcont dat Wind Erosion Control Factor Single none acw apexcont dat Rainfall Change E to W Single none bxct apexcont dat Rainfall Change S to N Single none byct apexcont dat Flood Routing Time Single none dthy apexcont dat Routing Threshold Single none qth apexcont dat 40 Interactive APEX i_APEX USERS GUIDE Table A 1 continued Name ID Type Units Description APEX File Routing when Reach Storage Single none stnd apexcont dat Basin Channel Length
52. e dat Daily Manure Dump Single ke hd d dump iasite dat Manure Id Integer none idmu iasite dat Urine Volume Single I hd d vurn iasite dat Interactive APEX i APEX USERS GUIDE 41 Table A 3 Subarea Name ID Type Units Description APEX File Subarea Id Long Integer none iasub dat Soil Id Long Integer none inps iasub dat Operation Schedule Id Lone Integer none iops iasub dat Owner Id Long Integer none iow iasub dat Feeding Area Long Integer none ii iasub dat Manure App Area Long Integer none iapl iasub dat Curve Number Type Integer none nvcn iasub dat Daily Weather Station Number Integer none iwth iasub dat Point Source Number Integer none ipts iasub dat Water Content of Snow Cover Single mm sno iasub dat Standing Dead Crop Residue Single t ha stdo iasub dat Subarea X Centroid Single none xct iasub dat Subarea Y Centroid Single none yet iasub dat Drainage Area Single ha wsa iasub dat Channel Length Single km chl iasub dat Channel Depth Single m chd iasub dat Manning N for Channel Single none chn iasub dat Slope Single m m stp iasub dat Slope Length Single m splg iasub dat Manning N for Upland Single none upn iasub dat Filter Strip Flow Fraction Single none ffpq iasub dat RR Channel Length of Routing Single km rchl iasub dat RR Routing Reach Channel Depth Single m rchd iasub dat RR Bottom Width of Channel Single m rcbw iasub dat
53. eath dat Monthly wind and weather One record per weather iawind dat data station per month Interactive APEX i APEX USERS GUIDE 3 Figure 1 i_ APEX Flow Chart Control Records Access Database Tables Yearly Output E J Selected Variables Average Output Crop Yield Output Monthly SWAT Output Organic C amp N Output Watershed Output Annual Pesticide Output Annual Pesticide Output 2 Annual Watershed Output Monthly Subarea Output Reside Output Soil Salt Output SWAT Output SWAT Output 2 SWAT Pesticide Output Subareas Management Livestock Livestock Schedule Point Source Field Operations by Management ID Crops Operations Fertilizer Pesticide Soils Weather by Weather Station ID Parameters by Parameter ID Soil Layers Weather by Month apex msa monthly subarea output apex awp annual watershed output apex swt daily output to SWAT apex acn soil layer C amp N data apex out general run data apex aps pesticide data apex acy crop yield data apex msw monthly output to SWAT apex sus subarea summar APEX2110 exe 4 EN 3 gt APEX Input Files apexfile dat filename list N iasite dat site file apexCont dat iaparm dat version parameters iatill dat operation list apexrun dat iaprnt dat output variables iafert dat fertilizer list iapest dat
54. fficient iaparm dat Parm87 Single none Not used iaparm dat Parm88 Single none Not used iaparm dat Parm89 Single none Not used iaparm dat Parm90 Single none Not used iaparm dat Parm91 Single none Cost 1 iaparm dat Parm92 Single none Cost 2 iaparm dat Parm93 Single none Cost 3 iaparm dat Parm94 Single none Cost 4 iaparm dat Parm95 Single none Cost 5 iaparm dat Parm96 Single none Not used iaparm dat Table A 15 Selected Variables Name ID Type Units Description APEX File Selected Variable Text none none iaprnt dat Variable Definition Text none none iaprnt dat 54 Interactive APEX i APEX USERS GUIDE Appendix B ACCESSI APEX Output Tables Table B 1 Average Output Name ID Type Units Description APEX File Farm Id Long Integer none none apex OUT Subarea Integer none none apex OUT Area by Field Single ha apex OUT Tmx Single mm Maximum Temperature apex OUT Prep Single mm Precipitation apex OUT Q Single mm Runoff apex OUT Prk Single mm Percolation apex OUT Yp Single kg ha Phosphorus loss with apex OUT sediment Ssf Single mm Subsurface flow apex OUT Rssf Single mm Subsurface flow that apex OUT returns to surface stream Yn Single kg ha Organic nitrogen loss apex OUT with sediment Qn Single kg ha NO3 loss in runoff apex OUT Ssfn Single kg ha Mineral nitrogen loss in apex OUT subsurface flow Prkn Single kg ha Mineral nitrogen loss in apex OUT percolat
55. g Configuration used to seti APEX program settings See Configuration Section S Interactive APEX i APEX USERS GUIDE 2 Edit command provides the user with an interface to edit i APEX ACCESS input tables Edit Header Information edit Control Record information Edit Parameters edit parameters for this control record All Crops edit crops All Operations edit operations All Fertilizers edit fertilizer entries All Pesticides edit pesticide entries 3 View Toolbar displays toolbar Status Bar displays status bar Chart Output not yet implemented Table Output not yet implemented Chart All Samples not yet implemented 4 Window window options 5 Select inoperative 6 Run Executes i APEX runs Output appends to existing ACCESS output tables Deleting of records may be performed in ACCESS This record run current control record All records execute multiple runs of APEX Run through allows user to set a range of control records to be run Stop if any precheck errors if precheck indicates errors in data do not run control records Stop if any run errors stop multiple runs if APEX error is encountered Realtime priority gives APEX absolute priority over all other processes Save input files saves the files apexcont dat iasub dat nnnn ops iaparm dat and apex OUT for all runs using the names nn_ia ext where nn is the control record number
56. ge Res 101 78 88 Wang X S R Potter J R Williams J D Atwood and T Pitts 2006 Sensitivity analysis of APEX for national assessment Trans ASABE 49 3 679 688 Williams J R 1990 The erosion productivity impact calculator EPIC model A case history Philosophical Trans BiologicalScience 329 1255 421 428 Williams J R W L Harman M Magre U Kizil J A Lindley G Padmanabhan and E Wang 2006 APEX feedlot water quality simulation Trans ASABE 49 1 61 73 Williams J W R C Izauralde and E M Steglich 2008 Agricultural Policy Environment eXtender Model Theoretical Documentation Version 0604 BREC Report 2008 17 Williams J R E Wang A Meinardus W L Harman M Siemers and J D Atwood 2006 APEX users guide V 2110 Temple TX Texas A amp M University Texas Agricultural Extension Service Texas Agricultural Experiment Station Blackland Research Center Yin L X Wang J Pan and P W Gassman 2009 Evaluation of APEX for daily runoff and sediment yield from three plots in the Upland Huaihe River watershed China Trans ASABE 52 6 1833 1845 38 Interactive APEX i_APEX USERS GUIDE Appendix A ACCESS i_APEX Input Tables Table A 1 Control Records Name ID Type Units Description APEX File Description Text none none apexcont dat State FIPS Long Integer none none apexcont dat C
57. haracteristics of reservoir all zeroes if no reservoir Auto Fertilization variables for the automatic application of fertilizer Lagoon variables describing lagoon characteristics Auto Irrigation variables for automatic irrigation 30 Interactive APEX i APEX USERS GUIDE Figure 18 Subarea Edit Window x Soil 84 CLYDE Select Edit Drainage area Conservation 1 Cancel practice Slope 0 02 Tillage Change Operation Add Operation Delete Operation 7 55 1 1 1 426 37 0 0 0 0 0 0 0 0 0 0 0 Siepe length 1 41113237 0 1500 0 0 0 0 0 0 0 500 0 Point souce number jo Feeding Area Non Manure Application Area Miscellaneous Grazing Channel Routing Reach Reservoir Auto Fertilization Lagoon Auto Irrigation Note None of the edit changes are written to the database until another control record is selected from the control record list ill Subareas Routing APEX allows up to four contiguous homogenous land use units or subareas Each subarea represents a landuse partitioning and runs off to the watershed channel stream Ultimately subsurface lateral return flow combines with runoff at the watershed outlet A complete set of input variables must be independently populated for each subarea including Field Operations Subarea edit window Figure 18 Buffers may be simulated by treating them as floodplains Floodplain modeling enables run on of runoff from t
58. he upslope subarea that borders on the floodplain Water and associated nutrients pesticides and sediment are drained onto the buffer floodplain soil surface Channel length CHL Channel window in the Subarea window Figure 18 Channel length of routing reach RCHL Routing Reach window in the Subarea window Figure 18 and Watershed area WSA WSA Drainage area for each Subarea Figure18 must be specified in order to lay out the routing schema for the watershed Extreme areas in a watershed furthest from the watershed outlet should make CHL RCHL A CHL gt RCHL indicates to the model that it is a downstream subarea A negative watershed area WSA indicates that the area of the subarea is added to another subarea s before reaching the downstream subarea Figure 19 shows routing for a watershed with four subareas from Steglich and Williams 2008 Subarea extreme area cotton peanut rotation WSA 50 ha Subarea 2 extreme area Pasture WSA 45 ha Subarea 3 downstream area Corn soy rotation WSA 70 ha Subarea 4 downstream area WSA 30 ha e CHL RCHL Extreme area headwaters CHL distance from subarea outlet to farthest point in subarea The distance is equal to the RCHL if the length of the routing reach is the same Interactive APEX i_APEX USERS GUIDE 31 as the CHL length As shown in the diagram an extreme subarea drains to the headwaters of the water reach Therefore a true routing reach
59. iable 10 Single various apex OUT Number Crops Integer none apex OUT Crop 1 Id Text none apex OUT Crop 1 Yield Single t ha apex OUT Crop 1 Biomass Single t ha apex OUT Crop 1 YIn Single kg ha Nitrogen in crop yield apex OUT Crop 1 Ylp Single kg ha Phosphorus in crop yield apex OUT Interactive APEX i_APEX USERS GUIDE 59 Table B 2 continued Name ID Type Units Description APEX File Crop 1 Fn Single t ha Nitrogen applied apex SUS Crop 1 Fp Single t ha Phosphorus applied apex SUS Crop 1 Water Stress Single days apex OUT Crop 1 Nitrogen Stress Single days apex OUT Crop 1 Phosphorus Single days apex OUT Stress Crop 1 Temperature Single days apex OUT Stress Crop 1 Curve Number Single none apex OUT Crop 2 Id Text none apex OUT Crop 2 Yield Single t ha apex OUT Crop 2 Biomass Single t ha apex OUT Crop 2 YIn Single kg ha Nitrogen in crop yield apex OUT Crop 2 Ylp Single kg ha Phosphorus in crop yield apex OUT Crop 2 Fn Single t ha Nitrogen applied apex SUS Crop 2 Fp Single t ha Phosphorus applied apex SUS Crop 2 Water Stress Single days apex OUT Crop 2 Nitrogen Stress Single days apex OUT Crop 2 Phosphorus Single days apex OUT Stress Crop 2 Temperature Single days apex OUT Stress Crop 2 Curve Number Single none apex OUT Crop 3 Id Text none apex OUT Crop 3 Yield Single t ha apex OUT Crop 3 Biomass Single t ha apex OUT Crop 3 YIn
60. iams X Wang A Saleh E Osei L M Hauck R C Izaurralde J D Flowers 2010 The agricultural policy environmental extender APEX model an emerging tool for landscape and watershed environmental analyses Trans ASABE 53 3 711 740 Hargreaves G H and Z A Samani 1985 Reference crop evapotranspiration from temperature Applied Engr Agric 1 96 99 Kellogg R L et al 2011 Assessment of the effects of conservation practices on cultivated cropland in the Chesapeake Bay Region Released February 2011 Conservation Effects Assessment Project USDA Natural Resources Conservation Service Washington D C Website http www nrcs usda gov technical nri ceap Kellogg R L et al 2012a Assessment of the Effects of Conservation Practices on Cultivated Cropland in the Ohio Tennessee River Basin Released February 09 2012 Conservation Effects Assessment Project USDA Natural Resources Conservation Service Washington D C Website http www nres usda gov technical nri ceap Kellogg R L et al 2012b Assessment of the effects of conservation practices on cultivated cropland in the Upper Mississippi River Basin Revised July 2012 Conservation Effects Assessment Project USDA Natural Resources Conservation Service Washington D C Website http www nrcs usda gov technical nri ceap Kellogg R L et al 2012c Assessment of the Effects of Conservation Practices on Cultivated Cropland in the Missouri River Basin Rele
61. iaparm dat Parm41 Single none Root temperature stress iaparm dat Parm42 Single none SCS curve number coefficient iaparm dat Parm43 Single none Plow layer depth iaparm dat Parm44 Single none Not used iaparm dat Parm45 Single none Sediment routing travel time iaparm dat coefficient Parm46 Single none RUSLE C factor coefficient residue iaparm dat Parm47 Single none RUSLE C factor coefficient biomass iaparm dat Parm48 Single none Adjust climate stress factor iaparm dat Parm49 Single none Canopy rainfall interception iaparm dat Parm50 Single none Rainfall interception coefficient iaparm dat Parm51 Single none Water storage of residue coefficient iaparm dat Parm52 Single none Till effect on decay rate iaparm dat Parm53 Single none Oxygen coefficient microbial activity iaparm dat Parm54 Single none Routing N enrichment coefficient iaparm dat Parm55 Single none Routing N enrichment exponent iaparm dat Parm56 Single none Fraction destroyed by burn iaparm dat Parm57 Single none Routing P enrichment ratio coefficient laparm dat Parm58 Single none Routing P enrichment ratio exponent iaparm dat Parm59 Single none P upward by evaporation iaparm dat Parm60 Single none Maximun grazing before rotation iaparm dat Parm61 Single none Soil water tension weighting iaparm dat Parm62 Single none Manure erosion eguation coefficient iaparm dat Parm63 Single none Pesticide loss coefficient iaparm dat Parm64 Single none Dust distribution coefficient iaparm dat Parm65 Single no
62. iaweath dat Wind Velocity ESE Single none dir 7 iaweath dat Wind Velocity SSE Single none dir 8 iaweath dat Wind Velocity S Single none dir 9 iaweath dat Wind Velocity SSW Single none dir 10 iaweath dat Wind Velocity SW Single none dir 11 iaweath dat Wind Velocity WSW Single none dir 12 iaweath dat Wind Velocity W Single none dir 13 iaweath dat Wind Velocity WNW Single none dir 14 iaweath dat Wind Velocity NW Single none dir 15 iaweath dat Wind Velocity NNW Single none dir 16 iaweath dat Table A 10 Crops Name ID Type Units Description APEX File Name Text none cpnm iacrop dat Category Integer none idc iacrop dat Biomass Energy Ratio Single none wa iacrop dat Harvest Index Single none hi iacrop dat Optimal Temperature Single c tb iacrop dat Interactive APEX i_APEX USERS GUIDE 47 Table A 10 continued Name ID Type Units Description APEX File Minimum Temperature Single c tg iacrop dat Maximum Leaf Area Index Single none dmla iacrop dat Growing Season Leaf Decline Single none dlai iacrop dat Leaf Development First Point Single none dlap1 iacrop dat Leaf Development Second Point Single none dlap2 iacrop dat Leaf Area Decline Rate Single none rlad iacrop dat Biomass Energy Decline Rate Single none rbmd iacrop dat Aluminum Tolerance Single none alt iacrop dat Maximum Stomatal Conductance Single none gsi iacrop da
63. ide Efficiency Ratio Appendix 1 Table 13 When performing modeling studies the USEPA assumes a default value of 5 drift and 95 reaching soil and plant surfaces Harvest Pesticide Efficiency Ratio 0 95 Pesticide applications have a Code variable value of 7 unless the application is by chemigation in which case the Code would be 8 Subareas The subarea edit window can be shown by double clicking on a subarea number entry in the Subarea list box Figure 18 It is used to edit variables found in the Subareas and Management tables of the database Variable fields in the upper left quadrant include subarea size conservation practice also known as P factor which indicates direction of tilling and cropping relative to field slope slope decimal fraction slope length distance in meters of subarea slope feeding area if pasture land being used by livestock and manure type manure application option as Non Manure Application Area Liquid Manure Application Area or Solid Manure Application Area In the lower left quadrant of this window are six buttons that describe aspects of the subarea being addressed including e Miscellaneous various subarea variables that don t fit in with the other seven categories Grazing number of animals and grazing limit for up to ten herds Channel characteristics of channel see routing Routing Reach characteristics of routing reach see routing Reservoir design c
64. ime from Max Single days ddlg iasub dat Liquid to Total Manure Ratio Single none solq iasub dat Auto Manure Application Rate Single kg ha fnp5 iasub dat Lagoon Safety Factor Single none sflg iasub dat Herd 1 Id Integer none ny 1 iasub dat Herd 2 Id Integer none ny 2 iasub dat Herd 3 Id Integer none ny 3 iasub dat Herd 4 Id Integer none ny 4 iasub dat Herd 5 Id Integer none ny 5 iasub dat Herd 6 Id Integer none ny 6 iasub dat Herd 7 Id Integer none ny 7 iasub dat Herd 8 Id Integer none ny 8 iasub dat Herd 9 Id Integer none ny 9 iasub dat Herd 10 Id Integer none ny 10 iasub dat Grazing Limit for Herd 1 Single t ha xtp 1 iasub dat Grazing Limit for Herd 2 Single t ha xtp 2 iasub dat Grazing Limit for Herd 3 Single t ha xtp 3 iasub dat Grazing Limit for Herd 4 Single t ha xtp 4 iasub dat Grazing Limit for Herd 5 Single t ha xtp 5 iasub dat Grazing Limit for Herd 6 Single t ha xtp 6 iasub dat Grazing Limit for Herd 7 Single t ha xtp 7 iasub dat Grazing Limit for Herd 8 Single t ha xtp 8 iasub dat Grazing Limit for Herd 9 Single t ha xtp 9 iasub dat Grazing Limit for Herd 10 Single t ha xtp 10 iasub dat Table A 5 Field Operations Name ID Type Units Description APEX File Subarea Id Long Integer none nnnn ops Year Long Integer none jx 1 nnnn ops Month Integer none jx 2 nnnn ops Day Integer none jx 3 nnnn ops Type Integer none jx 4 nnnn ops Tractor Long Integer none jx 5 nnnn ops Crop Id Integer none jx 6 nnnn ops 44
65. ingle m elev iaweath dat Years Max Month Records Single years ywi iaweath dat Wet Dry Probability Coefficient Single none bta iaweath dat Rain Distribution Single none expk iaweath dat Two Year 24 Hour Rainfall Single mm qg iaweath dat 46 Interactive APEX i_APEX USERS GUIDE Table A 9 Weather by Month Name ID Type Units Description APEX File Month Integer none iaweath dat Air Temperature Average Max Single c obmx iaweath dat Air Temperature Average Min Single c obmn iaweath dat Air Temperature Std Max Single c stmx iaweath dat Air Temperature Std Min Single c stmn iaweath dat Precipitation Average Single mm rmo iaweath dat Precipitation Std Single mm rst 2 iaweath dat Precipitation Skew Coefficient Single none rst 3 iaweath dat Probability Dry Wet Single none prw 1 iaweath dat Probability Wet Wet Single none prw 2 iaweath dat Rain Days Average Single days uavm iaweath dat Rain Half Max Single none wi iaweath dat Solar Radiation Single mj ly obsl iaweath dat Relative Humidity Single none rh iaweath dat Average Velocity Single m s uavm iaweath dat Wind Velocity N Single none dir 1 iaweath dat Wind Velocity NNE Single none dir 2 iaweath dat Wind Velocity NE Single none dir 3 iaweath dat Wind Velocity ENE Single none dir 4 iaweath dat Wind Velocity E Single none dir 5 iaweath dat Wind Velocity SE Single none dir 6
66. is MN August 10 14 Ritchie J T 1972 Model for predicting evaporation from a row crop with incomplete cover Water Resour Res 8 5 1204 1213 Saxton K E and W J Rawls 2006 Soil water characteristic estimates by texture and organic matter for hydrologic solutions Soil Sci Soc Am J 70 1569 1578 Steglich E M and J W Williams 2008 Agricultural Policy Environmental eXtender Model User s Manual Version 0604 BREC Report 2008 16 AgriLIFE Research Blackland Research and Extension Center 720 East Blackland Road Temple Texas Steglich E M and J W Williams Draft 2011 Agricultural Policy Environmental eXtender Model User s Manual Version 0806 BREC Report AgriLIFE Research Blackland Research and Extension Center 720 East Blackland Road Temple Texas Waidler D M White E M Steglich X Wang J W Williams C A Jones and R Srinivasan June 2011 Conservation Practice Modeling Guide for SWAT and APEX AgriLIFE Research amp Extension Texas A amp M System Texas Water Resources Institute Technical Report No 399 Texas A amp M University System College Station Texas Wang X January 2013 Personal communication AgriLIFE Research amp Extension Texas A amp M System Temple Texas Wang X P W Gassman J R Williams S Potter and A R Kemanian 2008 Modeling the impacts of soil management practices on runoff sediment yield maize productivity and soil organic carbon using APEX Soil Tilla
67. le days apex OUT Crop 2 Phosphorus Single days apex OUT Stress Crop 2 Temperature Single days apex OUT Stress Crop 2 Curve Number Single none apex OUT Crop 3 Id Text none apex OUT Crop 3 Yield Single t ha apex OUT Crop 3 Biomass Single t ha apex OUT Crop 3 YIn Single kg ha Nitrogen in crop yield apex OUT Crop 3 Ylp Single kg ha Phosphorus in crop yield apex OUT Crop 3 Fn Single t ha Nitrogen applied apex SUS Crop 3 Fp Single t ha Phosphorus applied apex SUS Crop 3 Water Stress Single days apex OUT Crop 3 Nitrogen Stress Single days apex OUT Crop 3 Phosphorus Single days apex OUT Stress Crop 3 Temperature Single days apex OUT Stress Crop 3 Curve Number Single none apex OUT Crop 4 Id Text none apex OUT Crop 4 Yield Single t ha apex OUT Crop 4 Biomass Single t ha apex OUT Crop 4 YIn Single kg ha Nitrogen in crop yield apex OUT Crop 4 Ylp Single kg ha Phosphorus in crop yield apex OUT Crop 4 Fn Single t ha Nitrogen applied apex SUS Crop 4 Fp Single t ha Phosphorus applied apex SUS Crop 4 Water Stress Single days apex OUT Crop 4 Nitrogen Stress Single days apex OUT Crop 4 Phosphorus Single days apex OUT Stress Crop 4 Temperature Single days apex OUT Stress Crop 4 Curve Number Single none apex OUT Crop 5 Id Text none apex OUT Crop 5 Yield Single t ha apex OUT Crop 5 Biomass Single t ha apex OUT Interactive APEX i_APEX USERS GUIDE 57 Table B 1 continued
68. ltivation at Start MUSI param 4 N Concentration in Rainfall Irrigation water NO3 ppm Field capacity method Peak runoff energy adjustment Denitrification Me EPIC C Kemanian Auto P MNUL Manure application code 0 for automatic application to subarea with minimum labile P 1 for variable P rate limits on annual application based on January 1 labile P concentration 2 for variable N rate limits on annual application based on January 1 labile P concentration coa vn Header 4 Window Header 4 Figure 8 includes miscellaneous variables found in the Control Records table that effect e air quality atmospheric CO2 pest damage direction from which precipitation is advancing watershed flow rate exponent groundwater flushing rate return flow channel dimensions C factor pond presence upland slope groundwater storage floodplain infiltration rate and width used in characterizing field buffers return flow e Irrigation water nitrate 16 Interactive APEX i_APEX USERS GUIDE Figure 8 Header 4 Run Header Air Quality Analysis Ave Upland Slope Print monthly subarea out file Channel_Bottom_Width Pest damage scaling factor Maximum Groundwater Storage Change in rainfall E to W Saturated Conductivity Adjustment Change in rainfall S to N Floodplain Saturated Conductivity Exponent in Watershed Flow Rate Eq Floodplain Width Groundwater residence time Return Flow a a TTT Basi
69. matic irrigation may be input by selecting the Auto Irrigation button in the Subarea Edit Window Figure 18 Manual Irrigation is applied as a field operation with depth and date applied input in the Subarea Edit Window in the Operations section Figure 18 Six irrigation types are available by assigning the Irrigation code IRR in the Auto Irrigation window one of the following options 0 Dryland 1 Sprinkler irrigation 2 Furrow flood irrigation 3 Fertigation 4 Lagoon and 5 Drip irrigation Irrigation may be partitioned between runoff and infiltration using the Irrigation Runoff Ratio EFI in the Auto irrigation window to designate the volume fraction that may run off Figure 18 The manual irrigation type and EFI can be assigned in the field operations section of the Subarea window 28 Interactive APEX i APEX USERS GUIDE Evapotranspiration Evapotranspiration can be modeled in APEX using one of five alternative methods Header 2 Figure 6 e Penman 1948 requires daily recorded values for maximum and minimum air temperatures precipitation solar radiation average wind speed and relative humidity e Penman Monteith Monteith 1965 requires daily recorded values for maximum and minimum air temperatures precipitation solar radiation average wind speed and relative humidity e Priestly Taylor 1972 requires daily recorded values for maximum and minimum air temperatures precipitation and s
70. mp FLOODPLAIN 0 001_ 1 SMALL VALUES REDUCE CHANNEL amp FLOODPLAIN EVAPORATION PRMT 92 RUNOFF VOLUME ADJUSTMENT FOR DIRECT LINK NVCN 0 0 1 2 0 INVERSELY RELATED TO RUNOFF USED LIKE PRMT 42 INCN INDEX METHOD NVCN 4 PARM 93 to PARM 96 contain cost parameters 72 Interactive APEX i_APEX USERS GUIDE
71. n channel slope Atmospheric CO2 Basin channel length Irrigation water NO3 Reach channel USLE C factor ISAP Number of subarea to print monthly OUT file for 1 subarea Fraction controlled by ponds coma tte Header 5 Window Header 5 Figure 9 includes variables found in the Control Records table regarding e field dimensions and direction soil particle diameter wind erosion control factor water erosion equation grazing limit herds routing parameters soil field capacity fraction irrigation salt concentration nitrogen in rainfall Interactive APEX i APEX USERS GUIDE 17 Figure 9 Header 5 Run Feria AS cc Soma Header 1 Header2 Header3 Header4 Header5 Field Length A Routing for reach storage jo Field Width a Water erosion equation i Clockwise angle of field from north i N in Rainfall i Soil particle diameter p Herds Wind erosion control factor p e Grazing limit E 0 Time interval for flood routing i e Routing theshold o e Fraction field capacity 1 Irrigation Salt Concentration p 0 FL Field length 7 1 km Ifwind erosion is to be considered variable ACW gt 0 field dimensions and orientation must be specified If wind erosion is simulated for specific sites FL FW and ANG can be B measured easily However hypothetical sites are often used in long term simulations associated with large scale decision making In such cases values of FL FW and ANG should
72. namics MUST sediment yield coefficient delivery ratio at edge of field or watershed to SWAT modeling groundwater storage Interactive APEX i APEX USERS GUIDE 21 Figure 13 Parameters 4 Parameters Parameters 5 Parameters 6 Parameters 7 Parameters 1 Parameters 2 Parameters 3 o va TTL Soluble C adsorption fi 0 Max depth of mixing Frozen soil CN adjustment 0 05 Organic P loss exponent Hargraves PET eq coef 0 0032 MUST sediment yield coef Pesticide leaching ratio fo Hargreaves PET eq exp Root sloughing coef 5 Denitification soil water Maturity at spring growth fo 05 Denitification rate constant CEC effect on nitrification 0 3 Daily mineralization lower Not used 5 Water stress weighting Biological mixing efficiencyl 1 SWAT delivery ratio Soluable P runoff exp 1 3 Groundwater storage n Cancel Help Parameters 5 Window See Appendix 1 Table 14 for APEX2110 parameters Appendix 3 for APEX0806 Parameters 5 in Figure 14 includes variables regarding root temperature stress variable runoff curve number variables flow layer depth sediment routing time C factor variables used in RUSLE erosion calculations rainfall interception and climate stress factors water storage of residue coefficient tillage effect on microbial factors oxygen eguation of microbial activity nitrogen and phosphorus factors fraction burned maximum grazing before rotation 22 Interactive APEX i APEX USERS GUIDE
73. ne Not used iaparm dat Parm66 Single none Not used iaparm dat Parm67 Single none Dust distribution dispersion exponent iaparm dat Parm68 Single none Manure erosion exponent iaparm dat Parm69 Single none Adjust microbial activity function iaparm dat Parm70 Single none Microbial decay rate coefficient iaparm dat Parm71 Single none Manure erosion coefficient iaparm dat Parm72 Single none Volatilization nitrification coefficient iaparm dat Parm73 Single none Hydrograph development parameter iaparm dat Parm74 Single none Not used iaparm dat Parm75 Single none Furrow irrigation erosion coefficient iaparm dat Parm76 Single none Furrow irrigation sediment iaparm dat Parm77 Single none Runoff delay pest application iaparm dat Interactive APEX i_APEX USERS GUIDE 53 Table A 14 continued Name ID Type Units Description APEX File Parm78 Single none Soil water delay tillage iaparm dat Parm79 Single none Standing dead fall rate coefficient iaparm dat Parm80 Single none Puddling saturated conductivity iaparm dat Parm81 Single none Technology coefficient iaparm dat Parm82 Single none Runoff CN rainfall intensity iaparm dat coefficient Parm83 Single none Regulates lateral hydrologic iaparm dat conductivity Parm84 Single none P flux between labile active pool iaparm dat coef Parm85 Single none P flux between active stable pool iaparm dat coef Parm86 Single none N upward by evaporation coe
74. nrichment Ratio Method APEX 5 GLEAMS Non Varying Curve Number jo Runoff Estimation Methodology en estimate of Q z Pesticide output in Mass and or Concentration Soluble P Runoff Approach Gleams Pesticide v Auto mow interval o a EPIC oxygen depth Kemanian carbon clay IET Potential ET Equation Used to select which equation will be used to calculate Potential ET 1 Penman Monteith default when IET 0 2 Penman 3 Priestley Taylor 4 Ei Hargreaves 5 Baier Robertson Requires the entry of ELEV elevation WVL 1 12 wind velocities even if wind erosion is not considered and RH 1 12 relative humidity 1 Blank if Header 3 Window Header 3 Figure 7 includes variables found in the Control Records table regarding e slope length steepness C N P and manure dynamics lagoon pumping day grazing effects cultivation years at start of run field capacity wilting point estimation method MUSI erosion parameters peak runoff rate rainfall energy adjustment factor Interactive APEX i_APEX USERS GUIDE 15 Figure 7 Header 3 Run Header Header 1 Header2 Header3 Header4 Header 5 Slope Length Steepness Factor a RUSLE C MUSLE Flood routing Manure Application Method Auto application with minimum labile P Atmosheric CO2 Code CO2 concentration ppm Day to Pump Lagoon MUSI param 1 Manure Scrapping Interval MUSI param 2 Grazing Limit MUSI param 3 Years Cu
75. nteractive APEX i_APEX USERS GUIDE 33 Figure 20 Subarea Field Operation Addition Edit Change Operations PLRG12RwW Year Cancel Month Runoff curve number Tl Day Water stress factor Type Parameter 4 Tractor Population m2 Crop Id Max annual N Frac of season Years until trees are Potential Heat 1500 A Calibration and Validation of APEX Using i_APEX Calibration and validation of APEX with measured data can significantly increase the accuracy of modeling results Methods for performing model calibration and validation are described in the APEX manual Steglich and Williams 2008 APEX documentation Williams et al 2008 and the conservation modeling guidance report by Waidler et al 2011 Calibration adjustments of i APEX variables are typically based on time periods days months or years that encompass several years of measured data Variable adjustments are made until model results optimally correlate with measured results based on statistical performance Adjustments of variables during the validation period are based on calibration results Model calibrations and validations are most often performed by adjusting parameters that effect Hydrology Runoff Curve number CNIC and CN2 Irrigation partitioning Evapotranspiration Erosion and sedimentation RUSLE C Factor 34 Interactive APEX i_APEX USERS GUIDE Soils Soil water holding capacity parameters Nutrients Hydrology parameter
76. nw Single apex OUT Qps Single apex OUT Qpw Single apex OUT Ymus Single apex OUT Ymuw Single apex OUT Interactive APEX i_APEX USERS GUIDE 63 Appendix C APEX0604 and APEX0806 Miscellaneous Parameter Table Definitions THIS FILE CONTAINS DEFINITIONS OF S CURVE AND MISCELLANEOUS PARAMETERS USED IN APEX0604 20090630 S CURVE PARAMETERS AN S SHAPED CURVE IS USED TO DESCRIBE THE BEHAVIOR OF MANY PRO CESSES IN APEX THE Y AXIS IS SCALED FROM 0 1 TO EXPRESS THE EFFECT OF A RANGE IN THE X AXIS VARIABLE ON THE PROCESS BEING SIMULATED THE CURVE MAY BE DESCRIBED ADEQUATELY BY TWO POINTS CONTAINED IN THIS FILE IT IS CONVENIENT TO REPRESENT THE X AND Y COORDINATES OF THE TWO POINTS WITH TWO NUMBERS CONTAINED IN THIS FILE THE NUMBERS ARE SPLIT BY APEX THE X VALUE IS LEFT OF THE DECIMAL AND THE Y VALUE IS RIGHT OF THE DECIMAL THE TWO POINTS ARE CONTAINED IN AN ARRAY CALLED SCRP TO ILLUSTRATE THE PROCEDURE CONSIDER THE TWO SCRP VALUES IN THE FIRST LINE OF THE PARM1310 DAT FILE 90 05 99 95 SCRP 1 1 90 05 SCRP 1 2 99 95 WHEN SPLIT WE HAVE X1 90 Y1 0 05 X2 99 Y2 0 95 APEX USES THESE TWO POINTS TO SOLVE THE EXPONENTIAL EQ FOR TWO PARAMETERS THAT GUARANTEE THE CURVE ORIGINATES AT ZERO PASSES THROUGH THE TWO GIVEN POINTS AND Y APPROACHES 1 0 AS X INCREASES BEYOND THE SECOND POINT THE FORM OF THE EQ IS Y X X EXP B1 B2 X WHERE B1 AND B2 ARE THE APEX DETERMINED PARAMETERS S CURVE PARAMETER DEFINITIONS SCRP 1 N
77. ny method desired that have a populated record in the ACCESS Operations table e g spraying incorporation and knifing Incorporation and knifing can be indicated in the Operations table by providing a depth in millimeters to the variable labeled Tillage Depth Pesticide properties and application method affect pesticide losses as does application timing and are all indicated in the subarea operations Figure 18 Greater water runoff will enable increased pesticide runoff soluble and associated with sediment and is inversely proportional to soluble pesticide infiltration Pesticides with a Koc gt 5000 will have little or no infiltration when there is significant organic matter present except through macropores cracks and holes An APEX variable that impacts pesticide losses is the Pesticide Leaching Ratio in the Parameters 4 window Figure 13 which affects partitioning of the pesticide runoff to leaching ratio The Pesticide Leaching Ratio is typically set at 0 1 unless more specific information is available Another APEX variable that affects losses the Pesticide Loss Coefficient in the i APEX Parameters 6 Window Figure 15 represents the fraction of porosity that interacts with a pesticide as it leaches through the soil layer typically set at 0 1 unless more field specific information is available Pesticide drift losses during application can be estimated by the user by providing an application fraction to the variable Harvest Pestic
78. o been used in other studies such as by Yin et al 2009 in simulations of runoff and sediment yield from field plots in the Upland Huaihe River Watershed China APEX was designed to simulate agricultural management strategies for single field farms containing multiple contiguous fields grassed waterways filter strips and buffers and small watersheds It can also simulate non agricultural landscapes including urban settings The model operates with continuous simulations using a daily time step with as many years as desired Weather conditions precipitation air temperature solar radiation humidity and wind speed and direction soil conditions hydrology erosion sedimentation crop growth weed competition grazing irrigation tillage operations agricultural management and nutrient and pesticide dynamics are included in the simulations Hydrology aspects include overland and channel runoff subsurface flow deep percolation field sediment losses and evapotranspiration APEX and its field scale model predecessor the Environmental Policy Impact Climate EPIC model Williams 1990 have been extensively used to simulate nutrient pesticide and sediment movement EPIC has been used under numerous conditions in the U S and other countries Gassman et al 2005 and even at a global level Liu at al 2007 Since its inception in 1996 APEX modeling has been applied in multiple studies to evaluate the impact of agricultural practices e g Ram
79. of Org C in Biomass Single none fbm nnnn sol Fraction of Humus in Passive Single none fhp nnnn sol Interactive APEX i APEX USERS GUIDE 45 Table A 7 Soil Layers Name 1D Type Units Description APEX File Layer Number Integer none none nnnn sol Layer Depth Single m Zz nnnn sol Bulk Density Single t m 3 bd nnnn sol Wilting Point Single none none nnnn sol Field Capacity Integer none xids nnnn sol Albedo Single none salb nnnn sol Initial Water Content Single none ffc nnnn sol Minimum Water Table Depth Single m wtmn nnnn sol Maximum Water Table Depth Single m wtmx nnnn sol Initial Water Table Depth Single m wtbl nnnn sol Subsurface Flow Travel Time Single days rftt nnnn sol Initial Groundwater Storage Single mm gwst nnnn sol Maximum Groundwater Storage Single mm gwmx nnnn sol Return Flow Root Zone Single rfpk nnnn sol Maximum Layers Single none tsla nnnn sol Previous Years Cultivation Single years rtn1 nnnn sol Soil Group Type Single none xids nnnn sol Minimum Thickness of Maximum Single m zqt nnnn sol Layer Minimum Profile Thickness Single m zf nnnn sol Minimum Beginning Layer Single m ztk nnnn sol Thickness Fraction of Org C in Biomass Single none fbm nnnn sol Fraction of Humus in Passive Single none fhp nnnn sol Table A 8 Weather Name ID Type Units Description APEX File Name Text none iaweath dat Latitude Single degrees xlat iaweath dat Longitude Single degrees xlog iaweath dat Elevation S
80. olar radiation e Hargreaves and Samani 1985 requires daily recorded values for maximum and minimum air temperatures precipitation e Baier Robertson 1965 requires daily recorded values for maximum and minimum air temperatures and precipitation appropriate for cold climates APEX computes evaporation from plants and soils separately Ritchie 1972 Additional variables associated with these methods can be found in Parameters 3 Figure 12 and Parameters 4 Figure 13 The Hargreaves PET eguation exponent is particularly influential in its effect on evapotranspiration Wang et al 2006 Fertilization Like irrigation fertilization may be applied in two ways Automatic Specifications of automatic fertilization may be input by selecting the Auto Fertilization button in the Subarea Edit Window Figure 18 Manaal Fertilization is applied as a field operation with depth and date applied input in the Subarea Edit Window in the Operations section Figure 18 by selecting an ID from the ACCESS Fertilizer table Fertilizer may be applied in many different forms such as e Poultry manure Cattle manure Mineral phosphorus Anhydrous ammonia Mineral nitrogen N P K 28 10 10 Carbon nitrogen phosphorus and other nutrients enable the crop to grow Rate of crop growth is dependent upon nutrient availability chemical form and application method Initial soil nutrient levels should be input in the ACCESS Soils table
81. on Integer none masp apexcont dat Daily Output to SWAT Integer none iswt apexcont dat Enrichment Method Integer none iert apexcont dat Soluble P Runoff Approach Byte none ibp apexcont dat NP Uptake Code Integer none nupc apexcont dat Manure Application Code Integer none mnul apexcont dat Lagoon Pump Trigger Long Integer none ipd apexcont dat Interactive APEX i_APEX USERS GUIDE 39 Table A 1 continued Name ID Type Units Description APEX File Manure Scrapping Interval Long Integer none mscp apexcont dat Steepness Factor Code Integer none islf apexcont dat Air Quality Analysis Integer none naq apexcont dat Flood Routing Integer none ihy apexcont dat Atmospheric CO2 Code Integer none ico2 apexcont dat Field Capacity Method Integer none isw apexcont dat Subarea Print Code Integer none isap apexcont dat Peak Runoff Single none apm apexcont dat Rainfall Nitrogen Concentration Single none rfnc apexcont dat CO2 Concentration Single none co2 apexcont dat Irrigation NO3 Concentration Single none cqni apexcont dat Pest Damage Factor Single none pstx apexcont dat Grazing Limit Single none gzl0 apexcont dat Years Cultivation at Start Single none rtn0 apexcont dat Erosion Eguation Single none drv apexcont dat MUSI Parameter 1 Single none bus 1 apexcont dat MUSI Parameter 2 Single none bus 2 apexcont dat MUSI Parameter 3 Single non
82. op dat Plant Population Point 1 Single none smrl iacrop dat 48 Interactive APEX i_APEX USERS GUIDE Table A 10 continued Name ID Type Units Description APEX File Plant Population Point 2 Single none smr2 iacrop dat Lignin at Half Maturity Single none blgl iacrop dat Lignin at Full Maturity Single none blg2 iacrop dat Bk1 Single none bk1 iacrop dat Bk2 Single none bk2 iacrop dat Bk3 Single none bk3 iacrop dat Stx1 Single none stx1 iacrop dat Stx2 Single none stx2 iacrop dat Wub Single none wub iacrop dat Fto Single none fto iacrop dat Fit Single none flt iacrop dat Table A 11 Fertilizer Name ID Type Units Description APEX File Name Text none ftnm iafert dat Mineral Nitrogen Single none fn iafert dat Mineral Phosphorus Single none fp iafert dat Mineral Potassium Single none fk iafert dat Organic Nitrogen Single none fno iafert dat Organic Phosphorus Single none fpo iafert dat Ammonium Nitrogen Single none fnh3 iafert dat Organic Carbon Single none foc iafert dat Table A 12 Pesticide Name ID Type Units Description APEX File Name Text none pstn iapest dat Solubility Single none psol iapest dat Half Life Soil Single none phls iapest dat Half Life Foliage Single none phif iapest dat Wash Off Fraction Single none pwof iapest dat Organic Carbon Absorption Single none pkoc iapest dat Cost Single none pest iapest dat Interactive APEX i_APEX USERS GUI
83. ounty FIPS Long Integer none none apexcont dat SWAT Subbasin Long Integer none none apexcont dat NRIPTR Long Integer none none apexcont dat PSU Long Integer none none apexcont dat Point Integer none none apexcont dat HUC Long Integer none none apexcont dat MLRA Text none none apexcont dat Application Category Integer none none apexcont dat Nutrient Rate Category Integer none none apexcont dat Application Timing Integer none none apexcont dat Number Subareas Long Integer none none apexcont dat Weather Station Id Long Integer none none apexcont dat Simulation Length Long Integer none nybr apexcont dat Beginning Year Long Integer none iyr apexcont dat Beginning Month Long Integer none imo apexcont dat Beginning Dat Long Integer none ida apexcont dat Printout Interval Byte none apexcont dat Print Code Byte none idp apexcont dat Weather Input Code Integer none ngn apexcont dat Weather Random Cycles Byte none ign apexcont dat Weather Generator Stop Day Byte none igsd apexcont dat Leap Year Considered Integer none Ipyr apexcont dat Potential ET Long Integer none iet apexcont dat Stochastic Curve Number Long Integer none iscn apexcont dat Peak Rate Estimate Long Integer none ityp iasite dat Soil Profile Long Integer none ista apexcont dat Automatic Heat Unit Scheduling Long Integer none ihus apexcont dat Non Varying Curve Number Integer none nven0 apexcont dat Runoff Estimation Methodology Long Integer none infl apexcont dat Pesticide Mass and Concentrati
84. r none none apex ACN Year Integer none none apex ACN Total Organic N Single mm q apex ACN Total Organic C Single t ha y apex ACN Organic N Layer 1 Single apex ACN Organic N Layer 2 Single apex ACN Organic N Layer 3 Single apex ACN Organic N Layer 4 Single apex ACN Subarea Id Integer none none apex ACN Organic N Layer 5 Single apex ACN Organic N Layer 6 Single apex ACN Organic N Layer 7 Single apex ACN Organic N Layer 8 Single apex ACN Organic N Layer 9 Single apex ACN Organic N Layer 10 Single apex ACN Organic C Layer 1 Single apex ACN 62 Interactive APEX i APEX USERS GUIDE Table B 5 continued Name ID Type Units Description APEX File Organic C Layer 2 Single apex ACN Organic C Layer 3 Single apex ACN Organic C Layer 4 Single apex ACN Organic C Layer 5 Single apex ACN Organic C Layer 6 Single apex ACN Organic C Layer 7 Single apex ACN Organic C Layer 8 Single apex ACN Organic C Layer 9 Single apex ACN Organic C Layer 10 Single apex ACN Table B 6 Watershed Output Name ID Type Units Description APEX File Year Integer none none apex OUT Month Integer none none apex OUT Prep Single mm apex OUT Qss Single apex OUT Qsw Single apex OUT Qts Single apex OUT Qtw Single apex OUT Ys Single apex OUT Yw Single apex OUT Yns Single apex OUT Ynw Single apex OUT Yps Single apex OUT Ypw Single apex OUT Qns Single apex OUT Q
85. rop 5 Water Stress Single days apex OUT Crop 5 Nitrogen Single days apex OUT Stress Crop 5 Phosphorus Single days apex OUT Stress Crop 5 Single days apex OUT Temperature Stress Crop 5 Curve Single none apex OUT Number Table B 3 Crop Yield Output Name ID Type Units Description APEX File Subarea Id Integer none none apex ACY Year Integer none none apex ACY Crop Name Text none none apex ACY Grain Yield Single t ha none apex ACY Forage Yield Single t ha none apex ACY Biomass Single t ha none apex ACY Nitrogen Single kg ha fn apex ACY Applied Interactive APEX i_APEX USERS GUIDE 61 Table B 3 continued Name ID Type Units Description APEX File Phosphorus Single kg ha fp apex ACY Applied Nitrogen Stress Single days none apex ACY Water Stress Single days none apex ACY Table B 4 Monthly SWAT Output Name ID Type Units Description APEX File Year Integer none none apex MSW Month Integer none none apex MSW Runoff Single mm q apex MSW Sediment Single t ha y apex MSW N in Sediment Single kg ha yn apex MSW P in Sediment Single kg ha yp apex MSW N in Runoff Single kg ha qn apex MSW P in Runoff Single kg ha qp apex MSW Pesticide Name Text none none apex MSW Qpst Single none apex MSW Ypst Single none apex MSW Table B 5 Organic C and N Output Name ID Type Units Description APEX File Subarea Id Intege
86. s Application timing Application method Fertilizer type Nitrogen and phosphorus chemical and biological dynamic variables Pesticides Hydrology parameters Application timing Application method Pesticide properties Pesticide loss coefficient Pesticide Leaching Ratio Crop yield and heat units Simulated crop yields should be within 10 of measured yields Steglich and Williams 2008 Interactive APEX i_APEX USERS GUIDE 35 36 Interactive APEX i_APEX USERS GUIDE References Baier W and G W Robertson 1965 Estimation of latent evaporation from simple weather observations Canadian J Plant Sci 45 276 284 Borah D K G Yagow A Saleh P L Barnes W Rosenthal E C Krug and L M Hauck 2006 Sediment and nutrient modeling for TMDL development and implementation Trans ASABE 49 4 967 986 Gassman P W E Osei A Saleh and L M Hauck 2002 Application of an environmental and economic modeling system for watershed assessments J American Water Resour Assoc 38 2 423 438 Gassman P W J R Williams V W Benson R C Izaurralde L M Hauck C A Jones J D Atwood J Kiniry and J D Flowers 2005 Historical development and applications of the EPIC and APEX models Working Paper 05 WP 397 Center for Agricultural and Rural Development Iowa State University Ames Iowa Available at http www Card lastate Edu publications synopsis Aspx id 763 Gassman P W J R Will
87. t Critical Aeration Factor Single none caf iacrop dat Seeding Rate Single none sdw iacrop dat Maximum Crop Height Single m hmx iacrop dat Maximum Root Depth Single m rdmx iacrop dat CO2 Concentration Single ppm wac2 iacrop dat Nitrogen in Yield Single none cny iacrop dat Phosphorus in Yield Single none cpy iacrop dat Cky Single none cky iacrop dat Minimum Harvest Index Single none wsyf iacrop dat Pest Factor Single none pst iacrop dat Seed Cost Single kg cosd iacrop dat Price for Yield Single t pryg iacrop dat Water in Yield Single none WCy iacrop dat Nitrogen Uptake Emergence Single none bn1 iacrop dat Nitrogen Uptake Midseason Single none bn2 iacrop dat Nitrogen Uptake Maturity Single none bn3 iacrop dat Phosphorus Uptake Emergence Single none bpl iacrop dat Phosphorus Uptake Midseason Single none bp2 iacrop dat Phosphorus Uptake Maturity Single none bp3 iacrop dat Wind Erosion Factor Live Single none bwl iacrop dat Wind Erosion Factor Dead Single none bw2 iacrop dat Wind Erosion Factor Flat Single none bw3 iacrop dat Frost Damage First Point Single none frst1 iacrop dat Frost Damage Second Point Single none frst2 iacrop dat Vapor Pressure Deficit Single none vpth iacrop dat VPD Threshold Single none vpdl iacrop dat VPD Single none vdp2 iacrop dat Root Weight Emergence Single none rwpcl iacrop dat Root Weight Maturity Single none rwpc2 iacrop dat Germination Heat Units Single none gmhu iacrop dat Price for Yield Forage Single t pryf iacr
88. t growth Soil evaporation soil depth Harvest index crop maturity 35 35 Curve number soil water Soil cover estimate Tillage bulk density Aeration stress soil water N P plant stress Pest damage erature Water stress harvest index P use soil P concentration N volitilzation soil depth THAT AAT TAA Wind erosion vegetative cover SCRP1 1 Expresses the effect of soil course fragment content on plant root growth restriction X Course Fragment Parameters 2 Window See Appendix 1 Table 14 for APEX2110 parameters Appendix 3 for APEX0806 Parameters 2 in Figure 11 includes variables regarding 1st and 2nd S point curve values used estimating Runoff Curve Number Interactive APEX i_APEX USERS GUIDE 19 Figure 11 Parameters 2 Parameters Parameters 5 Parameters 6 Parameters 7 Parameters 8 Parameters 1 Parameters 3 Parameters 4 1st S Point Curve Soil temperature factor Plant population on USLE C Snow melt since snowfall Water stress water content CN2 upland slope steepness Feedlot dust moisture of litter Soil oxygen content Distance in spatial rainfall generator Water stress from soil Ground cover as funtion of Ground cover standing live biomass MT A Exception to s curve procedure Cancel Help Parameters 3 Window See Appendix 1 Table 14 for APEX2110 parameters Appendix 3 for APEX0806 Parameters 3 in Figure 12 includes variables regarding crop and soil effects on hydrologic cy
89. the Selected Output Variables box Thirty three of these output variables have been preselected in the i APEX Selected box and are always presented in the i APEX ACCESS output tables The user is allowed to select an additional 10 output variables from Selected Output Variables by clicking the Select Variable button To change a user selected variable highlight a variable in the User Selected box and click the Remove button to delete it Then go to the Selected Output Variables box and highlight a variable not already present in thei APEX Selected box and click the Select Variable box to add it to the User Selected box A complete list of APEX output variables is presented in the file output variables csv This file must be present in the run directory for i APEX to function The help file IApexHelp csv must be in the same directory as the database A check beside the Run APEX in visible console box allows the user to see APEX output to the screen Otherwise APEX runs will not be shown To the right is the box that invokes the Start with final soil button This button causes i_ APEX to rename previously created SOT soil files present in the run directory as the soil file input to APEX runs The Select Output Files button brings up a screen containing check boxes for each possible APEX output file When a file s box is checked that file is selected for output by APEX Output for only six of these files is captured in the database OUT ACY
90. the climate generator may be edited by selecting the Edit button in the Graphical user interface window 26 Interactive APEX i_APEX USERS GUIDE Figure 3 Availability of other measured parameters can be assigned to the Weather input code based on the designations above For example if only precipitation is available and the user needs other daily parameters to be generated the Weather input code 1 Measured precipitation must be available if daily temperatures and other measured parameters are to be used in the simulations When other measured data are available a 1 designation does not need to be input For example if all 5 parameters have measured values available the Weather input code 2345 In all simulations mean monthly weather data must be input into the ACCESS table Weather by Month Appendix 1 Table 9 Soils A soil may be selected by clicking Select in the upper right section of the Subarea window Figure 18 Selecting the Soil Edit button brings up the soil edit window and double clicking on the entries in the soil layer list box brings up an edit window for a particular soil layer A layer may be added by selecting the Add Layer button and editing values using the Edit Layer button To delete a layer click on the layer in the list box and select the Delete Layer button Alternatively soil may be added or altered using the Soils Appendix 1 Table 6 and Soil Layers Appendix 1 Table 7 ACCESS ta
91. trols A record from the list must be selected before that record in the Control Records table and the linked records in associated tables can be edited Edit Area Edit area fields allow editing of all variables in the current control record These include e Record IDs 12 Interactive APEX i_APEX USERS GUIDE Run Header Parameters Erosion Equation Weather Station Subarea variables Record IDs Record identifier fields state county etc are provided to the right of the control record list Identifiers are optional and may be left blank Run Header Selecting the Run Header button brings up the five Header buttons that account for variables contained in the Control Records table see Appendix 1 Table 1 These variables are written to the iasite dat and the apexcont dat files Placing the cursor on each variable field will display helpful information at the bottom of the Header screens Header 1 Window Header 1 Figure 5 includes variables regarding rain duration simulation timing print criteria random number generator cycles weather input code day weather generator stops grazing mode seed initialization field dimensions and angle wind speed power parameter and erosion soil particle diameter number of times generator seeds initialized Interactive APEX i_APEX USERS GUIDE 13 Figure 5 Header 1 Run Header Years of simulation duration Beginning year Beginning month Beginning da
92. urve 11 1 Single none P use soil P concentration 1 iaparm dat S Curve 11 2 Single none P use soil P concentration 2 iaparm dat S Curve 12 1 Single none N volatilization soil depth 1 iaparm dat S Curve 12 2 Single none N volatilization soil depth 2 iaparm dat S Curve 13 1 Single none Wind erosion vegetative cover iaparm dat S Curve 13 2 Single none Wind erosion vegetative cover 2 iaparm dat S Curve 14 1 Single none Soil temperature factor iaparm dat S Curve 14 2 Single none Soil temperature factor 2 iaparm dat S Curve 15 1 Single none Snow melt from snow fall 1 iaparm dat S Curve 15 2 Single none Snow melt from snow fall 2 iaparm dat S Curve 16 1 Single none Soil cover soil erature iaparm dat S Curve 16 2 Single none Soil cover soil erature iaparm dat S Curve 17 1 Single none Water stress water content iaparm dat S Curve 17 2 Single none Water stress water content 2 iaparm dat S Curve 18 1 Single none CN2 upland slope steepness 1 iaparm dat S Curve 18 2 Single none CN2 upland slope steepness 2 iaparm dat S Curve 191 Single none Feedlot dust moisture of filter 1 iaparm dat S Curve 19 2 Single none Feedlot dust moisture of filter 2 iaparm dat S Curve 20 1 Single none Soil oxygen content 1 iaparm dat S Curve 20 2 Single none Soil oxygen content 2 iaparm dat S Curve 21 1 Single none Distance in spatial rainfall generator 1 iaparm dat S Curve 21 2 Single none Distance in spatial rainfall generator 2 iaparm dat S Curve 22 Single none Not used iaparm
93. ve 1 1 Single none Coarse fragment root growth 1 iaparm dat S Curve 1 2 Single none Coarse fragment root growth 2 iaparm dat S Curve 2 1 Single none Soil evaporation soil depth 1 iaparm dat S Curve 2 2 Single none Soil evaporation soil depth 2 iaparm dat S Curve 3 1 Single none Harvest index crop maturity 1 iaparm dat 50 Interactive APEX i APEX USERS GUIDE Table A 14 continued Name ID Type Units Description APEX File S Curve 3 2 Single none Harvest index crop maturity 2 iaparm dat S Curve 4 1 Single none Curve number soil water 1 iaparm dat S Curve 4 2 Single none Curve number soil water 2 iaparm dat S Curve 5 1 Single none Water table ground water storage iaparm dat S Curve 5 2 Single none Water table ground water storage 2 iaparm dat S Curve 6 1 Single none Tillage Bulk Density 1 iaparm dat S Curve 6 2 Single none Tillage Bulk Density 2 iaparm dat S Curve 7 1 Single none Aeration Stress Soil Water 1 iaparm dat S Curve 7 2 Single none Aeration Stress Soil Water 2 iaparm dat S Curve 8 1 Single none N P plant stress 1 iaparm dat S Curve 8 2 Single none N P plant stress 2 iaparm dat S Curve 9 1 Single none Pest damage erature 1 iaparm dat S Curve 9 2 Single none Pest damage erature 2 iaparm dat S Curve 10 1 Single none Water stress harvest index 1 iaparm dat S Curve 10 2 Single none Water stress harvest index2 iaparm dat S C
94. y Printout interval Print code Monthlyouput S oy Random number generator cycles Weather input code 2 Grazingmode Manual Hybrid Automatic Compute latitude Day weather generator stops generating v Leap year considered Field length km Field width km Angle of field length from North clockwise degrees Power Parameter Soil Particle Diameter a NS AN s i Wind Erosion Control umrw wth Duration of Rain Times seeds initialized NBYR Number of Years of Simulation Duration The number of years of simulation can be any number from 1 up to hundreds of years However 20 to 30 years may be adequate to estimate frequency distributions used to solve many problems coa vn Header 2 Window Header 2 Figure 6 includes variables found in the Control Records table regarding e evapotranspiration plant N and P dynamics RCN estimator methodology non varying option output conversion Metric English rainfall peak rate enrichment ratio method auto mow minimum interval EPIC oxygen Kemanian carbon clay 14 Interactive APEX i APEX USERS GUIDE Figure 6 Header 2 Run Header Potential ET Hargreaves E N and P Plant Uptake a Smith Curve C SCuve Runoff curve number estimator Stochastic v Output Conversion Code s Metric C English Peak Rate Estimate Modified Rational EA v a NormalErosion Static Soil Profile Automatic Heat Unit Scheduling E

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