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1. on w c os 4 om oO len i Z D 206 N Q w a 2 a gt 5 0 0 O 03 21 04 48 05 16 06 13 07 14 08 08 09 05 10 03 03 24 04 18 05 16 06 13 07 14 08 08 09 05 10 03 Fat L SEhT Waters Fie Stren Crop Coefficient Root Zone Empty Dead WH Irrigation W Rain Source WSU AgWeatherNet Cweather wsu edu Dotted lines indicate forecast values Figure 29 Crop Coefficient Chart showing Cuttings Figure 30 Cutting dates shown on the Soil Water Chart Full Size Screen Version There is a version of this model that is set up for use on full size computer screens at http weather wsu edu Figure 31 The operation of this is essentially identical to the mobile version except that the charts are larger Making changes to fields in this version will apply the changes to the mobile version and vise versa Field Activity Reports One feature that is available on the full size version that is not available on the mobile version is the option to show a report of your interaction with the Irrigation Scheduler This was requested as a way to show certain agencies that you have been actively using the model for irrigation scheduling so that they will feel that incentives for irrigation scheduling are well spent The model counts the number of days that you view or edit that field in a month Figure 32 Views or Edits are counted whether you use the full page or small screen mobile version Loading2. ET information always overwrites forecasted values Forecast values are pulled when the field is first viewed once every two hours or after a change is made in Field Settings Maen Verizon 3G 11 18 AM 89 mm Verizon 3G 11 18 AM 6 s irrigation scheduler mobile 7 Day Daily Budget Table Field 7 Day Daily Budget Table Help Field Date Water Rain amp Avail Water Edit Data Help Use Irrig Water Deficit Date Water Rain amp Avail Water Edit Data i in hrs Use Irrig Water Deficit in in hrs 07 27 0 26 1 88 100 0 Cancel Irrigation hours _ Reset Correct Soil Water Availability ae ign A rT P y A i fi A 2 A Q2 kba tv FRO T V Y Irrigation 0 hours Reset Correct Soil Water Availability Set To Figure 11 Edit button expands table for inputs Figure 12 Reset Correcting Soil Water Availability Using the Edit Link on the Daily Budget Table Edit Data Clicking the Edit link on that day expands the screen to accept inputs for that day as shown in Figure 11 From here you can add or edit irrigation amounts Figure 11 or reset or correct the soil water availability to make it better match reality based on observations or soil moisture measurements Click Cancel closes the table up again You must click Save for these changes to be applied Irrigation Enter the net amount of irrigation applied to the field on this date If you chose to use hours instead of inches in Field
3. Please contact us and we would be happy to help add your network Table 1 Irrigation Scheduler Mobile currently can work with data from the following networks Network States Served Managed By Website AgWeatherNet Washington Washington State University http weather wsu edu CoAgMet Colorado Colorado State University http www coagmet colostate edu AZMET Arizona University of Arizona http ag arizona edu azmet NDAWN North Dakota North Dakota State University http ndawn ndsu nodak edu ADAWN South Dakota South Dakota State University http climate sdstate edu climate_site ag data htm CIMIS California California Dept Water Resources http wwwcimis water ca gov cimis welcome jsp AgriMet WA OR ID US Bureau of Reclamation http www usbr gov pn agrimet NV MT Alternative Crops and Crop Defaults Unfortunately crop coefficients are not always accurately transferrable from one climatological region to another Also the growth season dates used as defaults in the model obviously vary with different climates To account for this Irrigation Scheduler Mobile can accept different default crop coefficients and season growth dates that are attached to user defined groups of weather stations For example the model is now set up so that when a grower chooses a weather station in Western Washington the evergreen side it will use different crop coefficients that if a weather station in Eastern Washington the ever brown side is chosen Because of this dif
4. a full soil profile at field capacity This can be modified by using the Reset Correct Soil Water Availability option on the first day in the Daily Budget table Plant roots grow into soil at field capacity e Water moves quickly into the soil and excess water is lost quickly to deep percolation e All rainfall goes towards satisfying the calculated ET demand Using the Model Page Descriptions 7 Day Daily Budget Table The Daily Budget Table screen Figure 9 shows the most relevant values from a daily soil water budget and allows the user to edit the inputs for each day using the Edit link The data in each column is described below Water Use in day This is the daily crop water use evapotranspiration or ETc estimated from measured weather parameters from the selected weather station and the entered crop coefficients This model uses alfalfa reference evapotranspiration calculated using the standardized ASCE Penman Monteith method The model gets the weather data from the weather network when the model is first opened if it has been greater than two hours since the data was pulled or after a change is made in Field Settings Because of this if the weather network managers make corrections to the historical data for that weather station these changes are reflected in the model Rain amp Irrig in This is the sum of the measured rainfall at the weather station for that day and or and the irrigation amount Irriga
5. has the following benefits Benefits to the grower e Improved crop yields e Improved crop quality e Lower pumping energy costs e Lower irrigation related labor costs and e Decreased loss of expensive fertilizers to runoff or leaching Benefits to the environment e Less movement of fertilizers and pesticides with the water off of farms fields into streams water bodies and groundwater non point source pollution and e More water remains available in groundwater and in streams for alternative uses including fish and wildlife habitat Benefits for energy supply e Decreased irrigation energy pumping costs typical values are 10 20 savings and e Water remains in rivers to drive power generation turbines at multiple dam sites There are many irrigation scheduling tools available including paper and pencil versions e g Wright 2002 spread sheet versions e g Clark et al 2001 compiled program versions e g Rogers et al 2009 and online versions e g Hillyer and English 2011 However these tools are not widely used and most of them are not readily adaptable to the Pacific Northwest State The most common reason cited for not using these tools is that they are difficult to learn time consuming to use and that the grower does not feel that it is worth this time and effort required Agricultural producers are also rarely in the office and don t get many chances for and tend to not enjoy doing desk work A
6. irrigating again and they end up saving an irrigation or two over the season Moving Irrigation Sets With many irrigation systems it takes many days to irrigate an entire field This brings up the question Which date should put the irrigation on Simply choose one part of the field and throughout the whole season enter the irrigation on the date that that part of the field receives irrigation water Be aware that the soil water content in the other parts of the field will either be slightly ahead or behind the model It might be easier if you choose a location that is easier to remember when it was irrigated such as the first set If correlating correcting with soil moisture measurements be sure to choose the part of the field where the measurements are being taken Use with Soil Water Content Sensors Updating the model with periodic soil moisture measurements will greatly improve the accuracy of the soil moisture estimate These can be used to fine tune the model as well For example if you find that the soil moisture measurement is consistently higher than that estimated then the model is over estimating crop water use and the crop coefficients should be adjusted down for that time period Be aware that soil moisture measurements are quite variable and may be high one time then low the next Use seasonal trends and your good judgment to adjust the model Most soil water content sensors provide in the number as a volumetric soil water con
7. log in Figure 1 Bookmark this page or better yet put a shortcut icon on your mobile device s home screen for quick access in the future Figure 2 s Verizon 3G 11 01 AM 100 Eb irrigation scheduler mobile Login Add Bookmark Username O Password Coo Remember me Add to Reading List Add to Home Screen Mail Link to this Page For ername Forgot Password Register In order to use the irrigation scheduler please register for an AgWeatherNet Ee an lB eS Cancel Figure 1 Login Page Figure 2 iPhone Menu to Bookmark or add to your home screen u Verizon 3G 3 54 PM Verizon 3G 12 19 PM Irrigation Scheduler Mobile Welcome rtpeters 9 The Irrigation Scheduler lets you view weather wsu edu is ind G Search J store and analyze your irrigation water 6 6 0 usage based on crop type soil type and irrigation scheduler mobile historical water use data from a chosen weather network This can help you Add New Field make informed decisions on when and Help how much water to apply for maximum Check box to start with existing field crop yields and quality Field Name Field Year Get Started Network To get started click Add New Field and Station then select your crop type soil type and Field Crop closest weather station We ll do the rest l a Field Soil by filling in information based on your choices Later if you wish you can use Field Settings to person
8. the water stress status of the plant below MAD the crop water use is proportionately decreased as described in the user s manual Deep Water Loss Chart When more water is applied than can be held in the root zone soil water content exceeds field capacity then this water moves down past the bottom of the root zone and is lost to deep percolation The deep water loss chart Figure 20 shows the cumulative water losses to deep percolation a__ Verizon 3G 11 26 AM 100 E gt a Verizon 3G 10 23 AM irrigation scheduler mobile irrigation scheduler mobile Field Potatoes 2011 Potatoes v Field Potatoes 2011 Potatoes v Help Help Deep Hater Loss Chart q o Reduction Due to Hater Stress Percent M 05 09 05 27 06 14 07 02 07 20 08 07 087 25 05 09 05 27 06 14 07 02 07 20 08 07 08 25 Cumulative Deep Daily Deep Total estimate yield Water Loss 0 9 in Water Loss loss to water stress 62 Source WSU AsWeatherNet Cweather wsu edu Source WSU AgWeatherNet Cweather wsu edu Figure 20 Cumulative Deep Water Loss Figure 21 Corresponding Water Stress Chart Water Stress Chart This model uses a very simplified method of yield loss estimation When the soil water content goes below the red MAD line as in Figure 21 it is assumed that there is yield loss that is equivalent to the amount of decreased water use similar to Figure 8 In other words Y ET Yn ETm Or solved for yield Y Y X 2i O mM O ET where Y
9. welcome jsp AgriMet WA OR ID US Bureau of Reclamation http www usbr gov pn agrimet NV MT _ _ Verizon 3G 2 24 PM 77 E irrigation scheduler mobile Add New Field Help Check box to start with existing field FieldName sid Field Year Network Station http weather wsu edu Are you sure you want to delete this field This will delete all of the field settings and data Field Soil Select Soil Type B Field Crop Select staton E a ee patel OK O SE a a U M Figure 26 Add New Field Screen Figure 27 Warning before deleting field Additional information about each option figure 26 follows Field Name Use this to name the field Field Year This is the growing year If a previous year is selected then that previous year s weather data will be used in the water budget Use the current year for ongoing or current irrigation scheduling Network Pick the agricultural weather network from your state that has the station that best represents your location A list of agricultural weather networks whose data can be accessed by this irrigation scheduling tool are given in Table 1 Weather Station This tool automatically pulls the calculated daily reference evapotranspiration ET rates and measured precipitation from this station Choose a station that best represents the weather conditions at your field Field Crop Based on the selected crop default growing season dates cro
10. AE N pannan i f Depth on 0 l l 0 Start Date 100 I 150 I 200 I 290 Emergence Canopy Crop Canopy Crop Initial End of Date Exceeds Full Cover Maturation Growing 10 of Field 70 of Field Season Day of Year Figure 24 How crop coefficients and root growth are defined by the parameters in Field Settings Add Delete Fields Selecting this menu brings up the screen in Figure 25 You can add a new field or completely delete an existing field from this menu Verizon 3G 11 20 T 88 mm ET wsu edu is ini Gf Search irrigation scheduler mobile Manage Fields Field Add New Field Delete Selected Field Help Figure 25 Manage Fields Screen Add New Field Use this to add a new field Delete Selected Field Permanently removes the currently selected field and all of its settings and associated data Table 1 Irrigation Scheduler Mobile currently can work with data from the following networks Network States Served Managed By Website AgWeatherNet Washington Washington State University http weather wsu edu CoAgMet Colorado Colorado State University http www coagmet colostate edu AZMET Arizona University of Arizona http ag arizona edu azmet NDAWN North Dakota North Dakota State University http ndawn ndsu nodak edu ADAWN South Dakota South Dakota State University http climate sdstate edu climate site ag data htm CIMIS California California Dept Water Resources http wwwcimis water ca gov cimis
11. Frek Soil Hater Content Rain amp Irrigatio 10 05 09 05 27 06 14 07 02 07 20 08 07 08 25 05 16 05 31 06 15 06 30 07 15 077 30 08 14 Full Soil Water First Stress Full Soil Water First Stress Empty Dead Irrigation W Rain Empty Dead WH Irrigation W Rain Dotted lines indicate forecast values Dotted lines indicate forecast Values Figure 14 Soil Water Chart Figure 15 Shows how water stress below the MAD line causes daily water use to decrease More Charts Clicking the More Charts button will give you access to the additional charts shown in Figure 16 that help you understand and evaluate your field and your soil water balance model Clicking Less Charts hides these charts again a Verizon 3G 11 26 AM LOVA E irrigation scheduler mobile lt lt lt lt lt Aug 02 2013 Forecast Field Potatoes 2011 Potatoes v Help Cunulative Hater Chart 05 09 05 27 06 14 07 02 07 20 08 07 06 25 Crop ET Irrigation W Rain Total 23 3 Total 22 Total 1 5 Source WSU AgWeatherNet Cweather wsu edu Figure 16 After clicking More Charts Figure 17 Cumulative Water Chart Cumulative Water Chart Figure 17 shows the cumulative crop evapotranspiration ETc or crop water use irrigation and rainfall over the specified growing season The season totals are given in the chart legend Crop Coefficient Chart Crop coefficients Kc are multiplied by the daily refe
12. Settings then you can enter this value in hours of irrigation run time Some applied irrigation water is lost to evaporation Therefore gross irrigation amounts must be discounted to account for irrigation inefficiency This is done by multiplying by the irrigation efficiency as a decimal 100 Typical irrigation efficiency values are drip 95 center pivot 85 wheel hand lines lawn sprinklers 70 big guns 60 For example a gross depth of 1 inch of water is applied by a center pivot enter 0 85 here 1 inch x 85 100 If you use measured application depths don t correct for efficiency For surface irrigation either use a very large number like 3 4 inches at each irrigation or a reasonable assumption is that you completely refill the soil to field capacity to 100 Available Water or completely replace the soil water deficit Reset Correct Soil Water Availability Check this box to overwrite the calculated percent of available soil water with an entered number Figure 12 You might want to do this to correct the model to make it better match observations or a soil moisture measurement The model will use your entered value as the new value and will calculate the estimated soil water content from that point on Unchecking this box will make model return to the calculated value Correcting Rainfall in Measured rainfall is automatically included from the weather station If you measured rainfall at your field and it differs significantly
13. alize or refine the default field settings for the selected crop and soil type Add New Field Figure 3 Welcome and Getting Started screen Figure 4 Setup a new field Logging in will bring up the screen in Figure 3 Click Add New Field to bring up the screen in Figure 4 where you can give the field a descriptive name chose the growing year past years are available for comparison purposes or what if scenarios choose the weather network from your state select the weather station in that network that is nearest or best represents your field s growing climate and select the crop grown and the soil texture Click Add Field and you re done with the setup Follow the on screen instructions Help is available for each page by clicking the Help link on that page Additional information is available below in the Using the Model In Depth Descriptions section Introduction Irrigation scheduling is finding the answers to two basic questions When do turn the water on and How long do leave it on Improved irrigation scheduling has tremendous public and private benefits It has been shown in various studies to decrease irrigation water use by 10 30 while resulting in equivalent or better crop yields and quality Since irrigation is responsible for 80 90 of the consumptive water use in most arid areas the total water and energy savings from improved irrigation management is tremendous Irrigation scheduling
14. and empty AWC times the soil depth gives the available water supply The Empty Dead permanent wilting point is calculated using this number and field capacity Soil Available Water Holding Capacity is measured in inches of water per foot of soil depth Management Allowable Deficit Abbreviated MAD this is the percent depletion of the total available water below which the plant begins to experience water stress 100 minus MAD is the First Water Stress point as a percent of the available water holding capacity As the soil dries down below this point the plant will experience increasing amounts of water stress until the plant will die when it reaches the Empty Dead permanent wilting point Daily crop water use estimates are proportionately decreased from the full value to zero as the soil water content decrease from MAD to the soil s permanent wilting point Planting Emergence Date Date the plant that the crop emerges and or the plant starts using water This is the start date for the soil water budget model See Figure 24 Crop Canopy Cover Exceeds 10 of Field The date that crop water use starts increasing See Figure 24 Crop Canopy Exceeds 70 of Field Full Cover Date The date that the crop canopy exceeds 70 80 of the field area or shades 70 80 of the ground area At this point the crop coefficient reaches a maximum and stays at this maximum until the Initial Maturation Date below See Figure 24 Crop Initial Matu
15. any page for the field is counted as a view Making an edit in the Daily Budget Table such as adding an irrigation event or in the Field Settings is counted as an edit C G Irrigation Scheduler Mo x 7 G Washington State Weathe x f Follow us on Facebook News Staff Popular Links Northwest Forecast Spokane Forecast State Climate Contact Us Help Home AWN Aoril 2013 Weather Review AWN Mobile eae Field Blasphemy 2013 Beets table x AWN Outlook AWN Frost Risk AWN Warnings Pictures Station Details Weather Widget Current Conditions Yesterday s Weather Want to Give Contact AWN Help 05 16 Full Soil Water First Stress Empty Dead MP Irrigation W Rain Dotted lines indicate forecast values glike Send Pj Sign Up to see what your friends like Figure 31 Full Screen version r m as Irrigation Scheduler Mo x 7 G Washington StateWeathe x 3 gt C f D weather wsu edu awn php page irrigation scheduler A Z Index Campuses myWSU WASHINGTON STATE The Washington Agricultural Weather Network Version 2 0 WSU Prosser NIVERSITY Wu AgWeatherNet World Class Face to Face f Follow us on Facebook News Staff Popular Links Northwest Forecast Spokane Forecast State Climate ContactUs Help Home Another unlucky tum Rein causes more problems with chery harvest AWN Mobile Sapa Field Areak Pasture 2013 Grass Pasture AWN News AWN Frost Risk AWN Warnings Stati
16. below MAD the stomata in the plant leaves will begin to close the leaves will often curl or droop and the plant will use less water and the growth will decrease The model estimates this decrease in water use according to Figure 8 Daily crop water use is proportionately decreased as the of available water decreases below MAD towards the PWP This follows the water stress coefficient Ks concept as described by Allen et al 1998 Irrigation scheduling for maximum crop growth requires maintaining the soil water content between field capacity and the MAD Different plants are more resistant to water stress than others and therefore the MAD for each crop may be different The default MAD values for the various crops are given in Appendix B 120 100 80 60 40 20 of Max Growth amp Water Use 0 O 10 20 30 40 50 60 70 80 90 100 Wilting MAD Field Point Capacity Available Water Figure 8 Water use is proportionately decreased as the of available water goes below the MAD Yield is also assumed to decrease in the same pattern Defaults values for MAD is set based on the crop chosen but can be modified in Advanced Field Settings Other Model Assumptions The following additional assumptions are made by this soil water balance model e All water entered as an irrigation amount infiltrates into the soil e Water in the plant s root zone is equally available to the plant regardless of depth e The season begins with
17. d its roots grow Root growth in Irrigation Scheduler Mobile is assumed to increase linearly from a beginning depth at the planting or emergence date and is assumed to reach their maximum depth at the same time the crop canopy reaches full cover or covers shades 70 80 of the field area Figure 6 After this time the root depth is assumed to remain constant until the end of the growing season Default values for the parameters that define the changing root zone depth for the various crops are given in Appendix B Maximum L 2 a tT A t 0 Root Zone Depth ft tn 100 150 200 250 Emeen Crop Canopy Full End of Growing Date Cover 70 of Field Season Day of Year Figure 6 Parameters that define the changing root zone depth Defaults values for these parameters are set based on the crop chosen but can be modified in Advanced Field Settings How Much Water is the Plant Using The amount of water required to grow a crop consists of the water lost to evaporation from a wet soil surface and leaves and transpiration of water by the plant Together these are called evapotranspiration ET and are also referred to as crop water use ET is measured in inches of water used per day The crop evapotranspiration E7 is calculated as ET K X ET where ET is the estimated evapotranspiration of a reference surface of full grown alfalfa that is calculated from measured weather data The weather data used to calculate ET inc
18. dry The soil s water holding capacity can be reduced by multiplying by this percentage to reflect this Soil Water Content at Field Capacity This is the maximum amount of water that the soil can hold long term against gravity After a soil is at the field capacity Full point adding more water will result in the water moving down through the soil profile and possibly past the bottom of the root zone tracked on the Deep Water Loss Chart Field Capacity is measured in inches of water per foot of soil depth all Verizon 12 58 PM ut Verizon weather wsu edu weather wsu edu Advanced Field Information Advanced Field Information Field Field Help Help Show Forecast Values Show Forecast Values O Send Me Notifications By O Send Me Notifications By Use Hours Irrigation Instead of Inches Use Hours Irrigation Instead of Inches For Drip Micro Irrigation Application of Soil Wetted Rate in hr Soil Water Content at know my Application Rate Field Capacity in ft Irrigation Type Soil Available Water Emitter flow rate Holding Capacity in ft Emitter line spacing in DS First Water Stress Distance between Point of drip lines 9 Emergence Application Efficiency Date Z Canopy Cover For Drip Micro Figure 22 23 Advanced Field Information Setup Screen Soil Available Water Holding Capacity AWC This is field capacity minus wilting point or the amount of water the soil can hold between full
19. eck this box to get email or text message notifications sent to you on the status of your field If you choose to be notified by email you will be asked for your email address If you choose to be notified by text SMS message you will be asked for your mobile phone number and your service provider You can also choose what time of day the notification will be sent You can also elect to only be notified when your percent of available soil water has been depleted to less than an entered threshold value See Figure 22 23 Use Hours Instead of Inches Many irrigators think in terms of hours of irrigation run time instead of inches of water applied Applied irrigation can be entered in hours and the soil water deficit can be displayed in hours instead of inches If you prefer to use hours an irrigation application rate in inches per hour must be provided Calculators are available on this page to Help Calculate My Application Rate for drip sprinkle and general irrigation systems using a variety of different units Reasonable assumptions of irrigation application efficiency are provided for each system See Figure 23 For Drip Micro of Soil Wetted In many perennial cropping systems under drip or micro irrigation the entire soil volume is not used For example a drip irrigation system in a wine grape vineyard may wet a 4 ft width of soil in an 8 ft row spacing In this case only 50 of the soil is used to store water since the inter rows remain
20. ferent states can also have their own set of default crops crop coefficients and growth season dates Please contact Troy Peters troy peters wsu edu for more information on how to get these made specific to your state or area References Allen R G L S Pereira M Sith D Raes and M Smith 1998 Crop Evapoatranspiration Guidelins for computing crop water requirements Irrigation and Drainage Paper 56 Food and Agiculture Organization of the United Nations Rome 300 pp ASCE EWRI 2005 The ASCE Standardized Reference Evapotranspiration Equation R G Allen A Walter R L Elliott T A Howell D Itenfisu M E Jensen and R L Snyder Reston VA ASCE The Irrigation Association Clark G D Rogers and S Briggemen KanSched A Water Management and Irrigation Scheduling Program for Summer Crops Available online at http mobileirrigationlab com kansched microsoft excel Last accessed 3 21 2012 Hillyer C and M English 2011 Irrigation Management Online Available online at http oiso bioe orst edu RealtimelrrigationSchedule Last accessed 3 21 2012 Peters R T K Desta and L Nelson 2012 Practical Use of Soil Moisture Sensors for Irrigation Scheduling WSU Extension publication Rogers D G Clark and M Alam KanSched2 Available online at http mobileirrigationlab com kansched2 Last accessed 3 21 2012 Wright J 2002 Irrigation Scheduling Checkbook Method Available online at http ww
21. from the existing value you can correct it by adding the difference as an irrigation If you measured less rainfall than the weather station reported you can subtract the difference by adding this difference as a negative irrigation value It makes the soil water chart look funny to plot that negative value but the math works correctly Additional Details Additional details of the daily soil water budget are available by clicking on the date Figure 13 This will expand the table to show these details The table can be returned to normal again by clicking the date again 5 46 PM Help Date Water Rain amp Avail Use in u Verizon 3G Edit Data Water Irrig Water Deficit in Day of Year 7 Measured Available Water 0 0 in 0 in 0 15 in 0 88 Irrigation Precipitation Reference ET Crop Coefficient Crop ET 0 13 in Root Depth 30 in Root Zone Water Deficit 0 39 in Modeled Available Water 93 Field Capacity 10 in Wilting Point 4 5 in Avail Water Capacity 5 5 in Water Storage At MAD 8 08 in Current Water Storage 9 61 in Volumetric Water Content 32 lt lt lt lt lt Aug 14 2013 Forecast Figure 13 Clicking on the date expands the table to show additional details for that date Soil Water Chart The soil water chart Figure 14 shows the estimated soil water content blue line over time in relation to the field capacity light green line management allowable dep
22. ield Capacity FC Total pore space Permanent Wilting Point PWP gt Oven Dry gt Figure 5 The various components of the soil water content As a plant s roots remove water from the soil the soil dries out to the point where the suction or pull of the soil on the water is greater than the plant s ability to absorb water At this point the plant will wilt and die Although there is water left in the soil from the plant s perspective the soil is empty This soil water content is referred to as the permanent wilting point PWP and is also measured in inches of water per foot of soil depth The difference between field capacity and permanent wilting point is known as the available water holding capacity AWC again given in inches of water per foot of soil depth AWC FC PWP Different soils have different available water holding capacities For example sand cannot hold as much water as a silt soil The default values of FC PWP and AWC that are used in this model for different soil textures are given in Appendix A A plant s rooting depth is also an important consideration A plant with deeper roots has access to much more soil and consequently has a larger reservoir of soil water to draw upon compared to plants with shallower roots The FC PWP and AWC are multiplied by the rooting depth to get the amounts of water held at those points in inches Rooting zone depths change over time as the plant an
23. irrigation scheduler mobile http weather wsu edu is User s Manual and Documentation R Troy Peters P E Ph D u Verizon 3G 9 02 AM 96 mm irrigation scheduler mobile Field Potatoes 2011 Potatoes v Help CASSE Soil Hater Content Rain amp Irrigation 05 09 05 27 06 14 07702 07 20 06 07 08725 Full Soil Water First Stress Empty Dead OF Irrigation W Rain Dotted lines indicate forecast values Table of Contents Quick Start Introduction Basics of Irrigation Scheduling and Model Assumptions How Much Water can the Soil Hold How Much Water is the Plant Using At What Point will the Plant Experience Water Stress Other Model Assumptions Using the Model In Depth Descriptions 7 Day Daily Budget Table Soil Water Chart More Charts Cumulative Water Chart Crop Coefficient Chart Daily Water Use Chart Deep Water Loss Chart Water Stress Chart Field Settings Add Delete Fields Forage Cuttings Full Size Screen Version Suggestions for Different Irrigation Cropping Systems Technical Details on Adapting the Model to Your Area References Appendix A Soil Defaults Appendix B Crop Defaults Quick Start To use the mobile irrigation scheduler you must have an AgWeatherNet user name and password This is free and easily set up on the AgWeatherNet website http weather wsu edu To start using Irrigation Scheduler Mobile point your mobile browser to http weather wsu edu is and
24. is the actual crop yield Ym is the maximum obtainable crop yield ET is the actual crop water use and ET is the maximum possible crop water use The right hand portion of this equation can be simplified as a crop water stress coefficient K that behaves as shown in Figure 8 as 7 ET SET The yield reduction on any particular day is therefore 1 Ks x 100 This is what is charted Figure 24 The season long total estimated yield loss due to water stress as shown on this chart is therefore calculated using the season long mean K Ks as 1 Kom X 100 Field Settings Field Settings allows users to select model interaction options and to change the field defaults that were chosen based on the crop and soil type chosen during field setup Default values for each crop and soil are in Appendix A amp B Entering alternate values here overwrites these defaults The Update Field button must be clicked for any changes to be applied Additional information about each option follows Show Forecast Values If checked the model will get a seven day forecast of the maximum and minimum temperatures from the National Weather Service based on the location of the chosen weather station The Hargreaves equation is then used to estimate grass reference evapotranspiration ETo and multiplied by 1 2 to estimate alfalfa reference evapotranspiration ETr Forecasts are refreshed every 2 hours See Figure 23 Send Me Notifications Ch
25. k al Verizon 3G 11 13 AM 100 Eb a Verizon 3G 11 22 AM 6 6 0 irrigation scheduler mobile 7 Day Daily Budget Table Field 7 Day Daily Budget Table Help Field Potatoes 2011 Potatoes D Date Water Rain amp Avail Water Edit Help Use Irrig Water Deficit Data Date Water Rain amp Available Water Edit in in in Use Irrig Water Deficit Data in in in ag Bo E Mo Tu We Th 7 A A A A f Y ad 4 A P a E JZ 1 Y o b ho f f j E Pa MN a ae Ze 0 21 28 lt lt lt lt lt Jul 12 2011 gt gt gt gt gt Figure 9 Daily Budget Table screen Figure 10 Expanded information for a date Forecast The last day on the Budget Table represents very early this morning A seven day forecast is available This forecast is based on the projected maximum and minimum temperatures from the National Weather Service NWS for those days at the latitude and longitude of the chosen weather station The Hargreaves equation is used with these temperature data to estimate grass reference ETo which is then multiplied by 1 2 for alfalfa reference ETr which is used in the model If the model is viewed late in the day the 7th forecasted day is from the NWS However before 6 PM the 6th forecasted day is repeated for the 7th forecasted day Irrigations can be entered in the future to do planning These irrigation events will remain as time passes from the future to the past Historical
26. letion MAD red line and the wilting point black line All of these may change over time as the soil volume available to the plant increases with the growing plant roots i e the upwards slopes in the first part of the season Enter irrigation events green points or correct the estimated available water content based on soil moisture measurements or estimates in the Daily Budget Table to make the soil water content better represent your field conditions Rainfall amounts are pulled from the weather station blue points If you find that this model is consistently off try editing the dates and crop coefficients in Field Settings Figure 15 is an example of a field where the irrigation system cannot keep up with crop water use demands and also shows how the model will modify daily crop water use numbers using the assumptions illustrated by Figure 8 As the soil dries below the First Stress MAD point the rate of drop in the soil water content decreases over time as the plant shuts down For maximum crop growth and production keep the soil water content blue line between the Full point or field capacity top green line and the and the First Stress MAD middle red line Verizon 3G 4 30 PM 88 u Verizon 3G 9 34 AM 87 mm irrigation scheduler mobile irrigation scheduler mobile Field Potatoes 2011 Potatoes v Field SE Corner 2013 Corn grain M Hel neip Field Soil Hater Content Rain amp Irrigation
27. lude solar radiation air temperatures humidity and wind speed data Irrigation Scheduler Mobile uses alfalfa reference ET as calculated by the ASCE standardized Penman Monteith Equation ASCE EWRI 2005 K is a crop coefficient specific to a crop and that crop s growth stage over the season Crop coefficients Irrigation Scheduler Mobile are mean crop coefficients and defined as in the FAO 56 publication Allen et al 1998 Figure 7 Default dates and crop coefficient values for different crop s are given in Appendix B 1 2 Full Cover 4 e SA U Ina re vam 0 6 GH Initial O 4 n Oo 0 2 I 100 I 150 i 200 i 2450 Emergence Canopy Crop Canopy CropInitial End of Date Exceeds Full Cover Maturation Growing 10 of Field 70 of Field Season Day of Year Figure 7 Parameters that define the crop coefficient curve The crop coefficient is multiplied by the alfalfa reference ET rate to determine the crop water use for that day Defaults values for these parameters are set based on the crop chosen but can be modified in Advanced Field Settings At What Point Will the Plant Experience Water Stress As water is removed from the soil through ET there is a point below which the plant experiences increasing water stress This point is known as the management allowable depletion MAD To manage the soil water for maximum crop growth depletion below this point is undesirable As the soil water content decreases
28. n on any mobile platform or directly from a full sized computer web browser There is a full size computer web browser interface from http weather wsu edu Background Information Irrigation Scheduling Basics and Model Assumptions Soil serves as a reservoir to store water and nutrients for use by the plant Knowing when to irrigate and how much water to apply requires knowledge of three things 1 How much water can the soil hold 2 How much water is the plant using 3 At what point soil water content will the plant begin to experience water stress Let s discuss each of these separately How Much Water Can the Soil Hold Water is held in the empty spaces between soil particles When these empty spaces are completely filled the soil is said to be saturated Figure 5 Excess water will drain out over time until a point where the soil can hold a certain amount of water indefinitely against the downward pull of gravity This soil water content is the soil s full point called field capacity FC and in this application is measured in inches of water per foot of soil depth The excess water that drains will move down to lower soil layers Applying more water than a soil can retain in the plant s managed root zone results in water loss to deep percolation DP or deep water loss Water loss to deep percolation wastes water pumping energy and vital plant nutrients that are held in the soil water solution Saturation F
29. nal Starting Max MAD Grain Spring Grain Winter Grapes juice Grapes wine Grass Hay Grass Pasture Grass Tall Pasture Grass Turf Hops Lentils Lettuce Melons Mustard Onions dry Onions green Peaches Pears Peas Peppermint Peppers Plums Potatoes Pumpkin Radishes Raspberries Appendix B cont Crop Defaults Used in the Model Continued Crop Development Dates for Crop Coefficient Curve DOY Crop Coefficients Root Depths ft Full Planting gt 10 o0f Cover gt Initial End of Full Crop Name Emergence Field 70 Maturation Season Initial Cover Final Starting Max Safflower Sorghum Soybeans Spearmint Spinach Squash Strawberries Sugar beets Sunflowers Tomatoes Tubers Watermelon Alfalfa and mint hay cutting lag and recovery periods are 7 and 14 days respectively They are 5 and 10 days respectively for grass hay
30. ntents Figure 16 Some descriptions of how the page operates Line Colors When the calculated soil water content is well above the MAD point and the plant growth should be at maximum then the row is highlighted green Figure 14 When the soil water content gets close to the MAD line only 15 of the readily available water remaining then the row turns yellow And when the soil water content goes below the MAD line the row is highlighted red as a warning of crop water stress The Most Important Number The most important value for irrigation scheduling is this morning s soil water deficit This is the amount of water that need to apply today to completely refill my soil profile If apply more water than this some will be lost to deep percolation because the soil can t hold it all It is highlighted in red can be seen in Figure 13 Navigation You can navigate to other dates in the growing season using the buttons at the bottom of the table The date button in the middle is used to go to the week starting with the chosen date Note that you cannot navigate outside of the growing season as defined by the crop s planting date and end of season or harvest date as defined in Field Settings The lt lt and gt gt buttons takes you to the beginning of the growing season and to today or to the growing season respectively The lt lt lt and gt gt gt buttons navigation you forward or backwards respectively in time by one wee
31. on Details Weather Widget Field Activity User Name tpeters Field Name Creek Pasture Weather Station WSU HQ WA Current Conditions Yesterday s Weather Soil Type Silt Loam Start Date Mar 05 2013 SES Crop Grass Pasture End Date Sep 05 2013 I Want to Give Contact AWN Month Year Days with Views Days with Edits Help May 2013 9 June 2013 11 July 2013 13 August 2013 13 slike amp Send Fa 7 people like this Sign Up to see what your friends like Figure 32 Field Activity report that is available from the full screen version Suggestions for Different Irrigation Cropping Systems Rill or Furrow Irrigation With surface irrigation methods it is difficult to know exactly how much water infiltrated into the soil A good assumption is that at each irrigation event you completely refill the soil water deficit to field capacity in the entire root zone Simulate this by entering a large number at each irrigation event like 3 4 inches entering a number equivalent to the soil water deficit or resetting the Percent Available Water number to 100 at each irrigation event The model is useful with surface irrigation in that it will indicate when the soil is getting dry again and when to irrigate To be the most efficient with your water resources wait to irrigate when the soil water content is near the First Stress MAD line Often growers learn they can wait a little longer than they thought before
32. p coefficients management allowable deficit MAD rates and rooting depths are chosen These crop parameters can be later edited in Field Settings Field Soil Based on the soil texture chosen default field capacity wilting point and water holding capacity values are chosen These soil parameters can be later edited in Field Settings Forage Cuttings Harvested forages such as alfalfa grass hay and sometimes mint can have multiple cuttings per season After a forage crop is cut the crop coefficients are greatly decreased since the height and leaf area of the forage has been removed The model knows which crops are forages and has default lag and recovery periods for these crops where the crop coefficients are temporarily reduced following a cutting Appendix B For these crops there will be an additional check box titled Apply Forage Cutting Today in the Edit expansion menu on the Daily Budget Table Checking this box on the day that the forage was cut will alter the crop coefficients during the recovery phase of the forage Figure 29 It will also put a mark on the Soil Water Chart to indicate the forage cutting Figure 30 u Verizon 3G 5 20 PM 81 mm Verizon 3G 9 17 AM 90 mm irrigation scheduler mobile irrigation scheduler mobile Field CutHay 2012 Grass Hay v Field CutHay 2012 Grass Hay v Help Help Crop Coefficient Chart Freza Soil Hater Content Rain amp Irrigatio j M N
33. ration Date After this date the crop begins to dry up senesce or otherwise shut down and water use begins to decrease See Figure 24 End of Growing Season Date Water use stops on this date Often this coincides with harvest or the first killing frost This is the last date of the model See Figure 24 Root Depth on Start Date The effects of a growing root depth is included in the soil water budget model This is the root depth in inches on the starting or plant emergence date See Figure 24 Maximum Managed Root Zone Depth This is the maximum root depth reached in the season It is assumed that the plant root reaches this depth on the Crop Canopy Full Cover Date See Figure 24 Initial Crop Coefficient The crop coefficient Kc from emergence to the 10 Cover date See Figure 24 This Kc is based on alfalfa reference ETr Full Cover Crop Coefficient The crop coefficient Kc at full cover This is the peak or maximum crop coefficient See Figure 24 This Kc is based on alfalfa reference ETr Final Crop Coefficient Crop coefficient Kc at the end of the season See Figure 24 This Kc is based on alfalfa reference ETr Crop Coefficient and Root Zone Depth Parameter Explanation Chart 1 2 T Full Cover Crop 6 Oo Coefficient E a 2 OOOO AOUN 5 a c Final Crop 08 ae Te oem U 9 w u 0 6 i lees Managed pT i Root Zone O 5 Initial Crop enii N Coefficient it 2 p n l O O 0 2 l i i 1 Root cc Q
34. rence alfalfa evapotranspiration ETr rate that is calculated from the measured weather parameters from your chosen weather station The Crop Coefficient Chart Figure 18 shows the crop coefficient curve used for this field over the growing season Also shown is the root zone depth over time The values that define these curves can be viewed and edited on the Advanced Field Settings page u Verizon 3G 11 26 AM 100 E gt ul Verizon 3G 11 25 AM 100 E gt irrigation scheduler mobile irrigation scheduler mobile Field Potatoes 2011 Potatoes y Field Potatoes 2011 Potatoes y Help Help Crop Coefficient Chart Daily Crop Hater Use m w D a A Re z D 15 N O a z z Z x a Pa 0 0 05 09 05 30 06 20 07711 08 01 08 22 Crop Coefficient Root Zone 05 09 05 27 06 14 07 02 07 20 08707 08 25 Source WSU AgWeatherNet Cweather wsu edu Source WSU AsWeatherNet Cweather wsu edud Figure 18 Crop Coefficient and Root Depth Chart Figure 19 Daily Crop Water Use Chart Daily Water Use Chart The Daily Water Use Chart Figure 19 shows the daily crop water use evapotranspiration or ETc over the specified growing season This is calculated as ETc ETr x Kc where ETr is alfalfa reference evapotranspiration and Kc is the crop coefficient for that day These values are affected by the weather hot dry sunny and windy days cause the plants to use more water the crop coefficients and
35. simple and user friendly irrigation scheduling tool that is accessible from a smart phone is needed to increase the adoption of data based irrigation scheduling Irrigation Scheduler Mobile is a soil water balance model that meets these requirements It is a free irrigation scheduling tool developed by Washington State University that is designed for use ona smart phone or on a desktop web browser for doing simplified check book style irrigation scheduling It is a basic soil water budget model In addition it has the following features It is simple to set up and intuitive to use There are help menus on each page It uses tables of default crop and soil parameters to simplify setup It automatically pulls daily crop water use evapotranspiration or ET estimates from a fairly expansive number of agricultural weather networks It is flexible enough to allow modifications by educated users for improved accuracy The model can be corrected using soil water measurements or estimates It includes a one week forecast of crop water use and soil water status for irrigation decision planning Growers can interact with it in terms of irrigation run time if desired instead of inches of water applied It readily displays useful charts and tables for visual evaluation of soil water status and model inputs It can send out push notifications to growers in the form of an email or as a text message Since it is designed as a web application it can be ru
36. tent water of total soil volume this number is available by clicking the date in the Daily Budget table for expanded information Figure 13 Use with Soil Water Tension Sensors Tensiometers and Granular Matrix Watermark sensors don t measure soil water content and therefore it is very difficult although not impossible to compare the measurements directly with the model However these sensors should indicate that the soil is drier greater soil water tension as the soil water content approaches and goes below the MAD line For additional help see the publication Practical Use of Soil Moisture Sensors for Irrigation Scheduling by Troy Peters The Effects of Irrigation Frequency With center pivots and some solid set irrigation systems water is applied much more frequently than other irrigation systems such as surface rill or hand lines and wheel lines High frequency irrigations mean that the soil surface and plant leaves are wet a greater percentage of the time and therefore a greater amount of water is lost to evaporation In other words the crop uses needs more water Because of this you might need to adjust the crop coefficients up 5 10 in Field Settings to compensate for this Deliberate Water Stress With some crops such as wine grapes it is desirable to deliberately cause water stress to get the desired crop quality results Recall that the plant will see approximately linearly increasing water stress from barely any at
37. the red First Stress MAD line to the black Empty Dead Permanent Wilting Point line see Figure 8 Deliberately causing stress is done by purposefully allowing the soil water to dry down below the First Stress line Figure 33 u Verizon 3G 9 08 AM 94 mm irrigation scheduler mobile Field WineGrapes 2012 Grapes wine v Help Field Soil Hater Content Rain amp Irrigatio 10 04 20 05 16 06 11 07707 08 02 08 28 09 23 Full oil Water First Stress Emptu Dead E Irrigation W Rain Dotted lines indicate forecast Values Figure 33 Water stressing wine grapes Irrigation after harvest was done to restore the health of the vines Technical Details on Adapting the Model to Your Area This model was set up to be used outside of just Washington State It was written in PHP and MySQL both of which are free open source applications that run on a web server The code is freely available under an open source GPL license if someone wants to set it up to run on a different server It is OK with the developers if this is re branded as long as the developers are acknowledged and it is freely available to users Other Weather Networks It can easily accept rainfall and weather data for evapotranspiration calculations from any weather network whose data can be accessed over the internet Additional states or networks can be fairly easily added if there is an automated way to get access to up to date historical weather data
38. tion events must be entered using the Edit link This is net irrigation not gross Some applied irrigation water is lost to evaporation Therefore gross irrigation amounts must be discounted for irrigation efficiency Typical irrigation efficiency values are drip 95 center pivot 85 wheel hand lines lawn sprinklers 70 big guns 60 For example a gross depth of 1 inch of water is applied by a center pivot enter 0 85 here 1 inch x 85 100 If you use measured application depths don t correct for efficiency For surface irrigation a reasonable assumption is that you completely refill the soil to field capacity or replace the soil water deficit Soil Water This is the calculated daily soil water content expressed as a percent of the available soil water 100 is equivalent to field capacity and 0 is equivalent to wilting point Entering a measured or estimated soil moisture value here using the Edit link will correct the model to the entered value from that day forward Volumetric soil water content for comparison with soil moisture sensor readings is available in the expanded information click the date Figure 13 Water Deficit in The soil water deficit in the root zone This is the amount of space in the soil or the depth of irrigation water that can be applied before the soil is full again reaches field capacity Edit Data Use this link at each line to add irrigation amounts or correct the model for measured soil water co
39. w extension umn edu distribution cropsystems DC1322 html Last accessed 3 21 2012 Appendix A Defaults by Soil Texture More accurate estimates for your particular soil are available from the NRCS Web Soil Survey http websoilsurvey nrcs usda gov app HomePage htm Soil Water Content in ft Field Wilting Soil Texture Capacity Point AWC Coarse Sand Fine Sand Loamy Sand Sandy Loam Fine Sandy Loam Sandy Clay Loam Loam Silt Loam Silty Clay Loam Clay Loam Silty Clay Clay Peat Mucks Appendix B Crop Defaults Used in the Model Alternative crops and defaults can be set up for different states or climatic regions Crop Development Dates for Crop Coefficient Curve DOY Crop Coefficients Root Depths ft Full Planting gt 10 o0f Cover gt Initial End of Full Crop Name Emergence Field 70 Maturation Season Initial Cover Final Starting Max Alfalfa Apples Apricots Asparagus Beans dry Beans green Beets table Blackberries Blueberries Bluegrass Seed Broccoli Brussel Sprouts Cabbage Canola Cantaloupe Carrots Cauliflower Celery Cheatgrass Cherries Clover Corn grain Corn sweet Cranberries Cucumbers Garlic Appendix B cont Crop Defaults Used in the Model Continued Crop Development Dates for Crop Coefficient Curve DOY Crop Coefficients Root Depths ft Full Planting gt 10 of Cover gt Initial End of Full Crop Name Emergence Field 70 Maturation Season Initial Cover Fi
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