MU Extension Crop Water User Manual
Contents
1. Authors Gene Stevens Zach Straatmann Joe Henggeler and Andrea Phillips Jones are located at the Fisher Delta Research Center in Portageville Missouri John Travios Stephen Martin Pat Guinan and Ray Massey are located on the University of Missouri campus in Columbia Missouri 74 ETo is multiplied by a crop coefficient which is specific for the crop and growth stage The crop coefficients except for rice come from UN Food and Ag Organization publication FAO 56 Beginning at planting growth stages are predicted from heat units for corn rice and cotton Calendar days are used for soybean This information is used to estimate daily crop water use ETs Soil Water Balance Daily soil water deficit is reported similar to a checkbook registry which tallies rainfall and irrigation as deposits and ETe as withdrawals The soil water deficit becomes more negative in periods of low rainfall When the soil profile is full field capacity the deficit balance is 0 As water is extracted the balance becomes negative Acknowledgements Funds for field research to validate this app were provided by Cotton Incorporated Howard G Buffett Foundation and United States Department of Agriculture Agricultural Research Service Getting Started Enrollment In a browser address box type this address to sign up and click Sign Up agebb missouri edu horizonpoint cropwater php Read the Terms of Use If you approv2. Figure 6 Select soil texture for each fi Although the lat long is locked in soil texture for a field can be changed later to a finer or coarser texture if needed Click on Submit and Back to Main Menu The next step is setting up crop information In the Main Menu click Setup Soils and Crops fourth row second column Then scroll to the field name and click on na under Crops in the second column Field Crop Information Feld mame Soybeans Group V No coo and plant ante cant charmed ore ats oon fo is fea ot yon a ca p Figure 7 Field Crop information page for entering field and crop information Select the planted crop in the field The default planting date is 12 31 Figure 7 Important If crop and planting date are not known yet do not guess Skip these boxes and come back later Other boxes on this page can be entered even if crop and planting date are not known Click Submit to save the information The next box on the page is Soil water deficit on planting date Figure 8 The soil water balance works on the same principle as a checkbook registry Like a checkbook CWU needs a beginning balance Unless spring rainfall has been usually low leave the default value on zero field capacity for initial soil moisture A field method for estimating soil moisture by hand was developed by USDA and can be found at this site http www nres usda gov wps portal nrcs detail mt newsroom cid nres144p2 200
3. 56492 Field Crop Information Figure 8 Select the most common rate of water that you will apply with the irrigation system Fill in the rest of the boxes on this page The effective root depth for most crops in Missouri is in the range of 18 to 24 inches If the soil has a restrictive layer from compaction enter a shallower depth During the season the rooting depth can be modified Select the irrigation method and default rate of water application Leave the allowable field water depletion at the default 50 unless you want to be more liberal with making irrigation applications Then click Yes on NWS Rainfall if you want the program to automatically enter the estimated rainfall amounts based on GPS locations of the field If you click yes during the season you will also have the option to substitute your rain gauge measurements for individual rainfall events or completely turn this feature off Click No to never use NWS rainfall estimates Now repeat the Setup steps for other fields until all are entered in the app Monitoring Daily Soil Water in Fields In the Main menu top row click Field Status or Field Summary to check daily water status in each field Field Status shows estimates for each field individually for the current day Figure 9 and Field Summary shows projected dryness indexes for all your fields for today and the next week assuming no rainfall occurs Figure 10 Lee Field 9 1 ron Coton
4. Flaningdate May 21 2014 Saite sitioam Roonngaepm 281m Allowable capleton 50 Deiautirigrale 2501n nt Status Estate Sun Juy i Cum growing degree day 901 Last water event at on FATA Pro ET crop onm Sol Water Balance 0 66 in ash oy E Iig viager MAD Figure 9 Field Status screen for checking daily soil water deficits in individual fields To navigate between fields in Field Status swipe your finger right to left or left to right across the bottom of the screen As the season progress your fields in Field Status will be sorted each day from driest to wettest soils The Dryness Index warns you when the soil water deficit is coming close to the Management Allowed Depletion MAD level of the field which is the recommended trigger for irrigation The symbols and XXX represent 70 80 90 and 100 of MAD respectively The value showing Left to trigger is the percentage remaining relative to MAD before the reserve water is used The text will change from green to yellow then red as the soil dries In Field Summary today s soil water deficit is shown for each field with the dryness index for today and the next week To see the most columns tilt the phone to landscape position Figure 10 Main menu screen for checking water dryness indexes for the next week As the crop grows and periods of low rainfall occur the values in the H20 deficit inches wil
5. Where Am I At Tunes app store Example Lat 36 4151365 Long 89 7010119 CWU uses positive decimal degrees Do not use minutes and seconds Main Screen Click on the bookmarked website address for your farm in browser The first screen that will appear in the app is Main Figure 4 This is the starting place to add new fields setting the soil and crop information monitoring daily soil moisture logging rainfall and irrigation amounts and requesting field reports aco ATAT F 0 54 AM ei Field Summary Add Add Rainfall Irrigation a Report fo Setup Soils and Crops o Figure 4 The main menu screen Field Setup Now click on Add Field in the third row In the next screen click on the top boxes and enter the field name and decimal degrees for north latitude and west longitude which are both positive real numbers Figure 5 If they enter west longitude as a negative number the program will correct it without error Be sure the correct GPS location for the field is entered before clicking Submit The title at the top of the page will change to Edit Field The location cannot be changed now but it is easy to delete and re enter a field Select the dominant soil texture for the field Figure 6 This is used to estimate available soil water holding capacity For more information about soils on your farm check the NRCS Soil Survey site httpy websoilsurvey sc egov usda gow Ap p HomePage htm
6. AGRICULTURAI PUBLISHED BY UNIVERSITY OF MISSOURI EXTENSION Crop Water Use Program for Irrigation Divisions of Plant Sciences Applied Social Sciences Food Sciences and Bioengineering and Soil Environmental and Atmospheric Sciences Water is an important factor affecting crop yields The University of Missouri Extension Service developed an on line program app to help farmers produce higher crop yields by improving irrigation management There is no charge to farmers This bulletin gives information about the Crop Water Use CWU application and explains how to set up fields to track soil moisture How Does The Application Work The application estimates crop water use from weather data An equation for calculating evaporation from soil and plants called evapotranspiration ET is used The application also calculates daily soil water deficit balances for each field Reports include indexes to help farmers determine when to irrigate Crop Water Use The University of MO Extension automatically downloads data each day from a mesonet of agricultural weather stations located across Missouri ET is calculated from solar radiation temperature humidity and wind CWU uses the Standardized short crop Penman Monteith Evapotranspiration ETo equation which was developed by a task committee of the American Society of Civil Engineers ETo is the amount of combined water lost from a reference crop grass and soil evaporation
7. e click I agree Figure 1 Enter information in the boxes Figure 2 Name phone number are optional Email address User Name password are required Horizon Figure 1 Introduction screen for CWU app Figure 2 Enter information and click submit Then on the third screen you will have the option to either launch the application now and bookmark the link or request the address by email Figure 3 Horizon Point Crop Water Use Application pei i Figure 3 Launch App or Request E Mail Link If you request email link an address with 32 random numbers and letters will be generated Only share your unique address with people that you trust You can copy Ctl C and paste Ctl V the address of the link to your computer and mobile phone This will save you time not having to type in a password every day to check your fields The Crop Water Use App requires daily weather from the Missouri weather station mesonet to function Currently the program only works when you have internet access by WiFi or a cellular data connection Before beginning the set up process it is best to write down on paper the names of all your fields with their latitude and longitude dominant soil texture and planned crop Latitude and longitude are used to estimate rainfall from the National Weather Service Find the fields location on Google Earth or go to each field and copy and paste the locations from an app such
8. e field setup for NWS rainfall compare your rain gauge measurement to the rainfall amount in the blue column remembering amounts are not posted at midnight If it does not agree closely click on the column to override the NWS amount Balance the value of exactness relative to the time required to enter rain amounts from gauges The daily reference ET values used in the CWU app is collected from the MU closest electronic water station to your field The main variable in the Penman Monteith equation is solar radiation which is more consistent across a region than rainfall Terms of Use The Crop Water Use Application is a weather based prediction model designed to aid farmers with irigation management Iti ot intended to be a substitute or scouting fields Always inspect soil and crop conditions in each ald betore deciding whether or not to irigale Under no circumstances including negligence shall the niversity of Missouri or its Board of Curators officers employees or agents be liable tor any incidental Indirect special or consequential damages including damages for loss of business profits business interruption and the like arising out ot the use misuse or inabilty to use this application or any related documentation Information is provided by the University ot Missouri Extension Commercial Agriculture Automated Weather Staton Network The Commercial Agriculture Automated Weather Station Network and the University
9. hen the dryness index does not match soil moisture sensors or visual crop water stress fine tune the field setup by adjusting the rooting depth or allowed depletion percentage Entering Rainfall and Irrigations Two options are available for entering rainfall and irrigation events Click on the water faucet symbol Figure 10 first column in a field row of Field Summary to navigate to the Add Edit Precipitation and Irrigation page Figure 12 If Yes was selected for NWS rainfall in setup the third column displayed will be NWS Precip To override NWS for a specific day enter the correct value in the blue column labeled Field Precip The rainfall amounts will be underlined indicating the CWU is using the new value for that day The NWS amount will still be displayed but it will not be used by CWU date Precittion and ian for Lee Field 12 1 Soybean ure 12 Page to edit precipitation rain and jation for amounts field To enter rainfall amounts in the program click on a cell in the light blue column 4th corresponding the date that water was applied Likewise for irrigation click on the green column far right The irrigation default rate that was entered in the setup will appear Figure 13 If needed it can be modified before clicking Submit When other fields receive the same amount of irrigation click the check boxes beside their names at the bottom of the page Unfortunately the 24 hour pe
10. l become more negative Soils have different water storage capacities so no single soil water deficit value is acceptable across all soils For example crops growing on sandy soil stress for water faster than crops on silt loam soil Factors used for calculating MAD are soil texture crop rooting depth and allowable depletion Soil texture is used to estimate available water holding capacity AWHC The formula for MAD is AWHC x Root Depth x Percent Allowable Depletion More details about water credits and debits is found in the Field Detail screen You can find this screen from the Main menu or clicking on a row in the Field Summary table This screen shows the daily values for crop ET inches of rainfall and soil water deficit for the last week Figure 11 To view more days click on All Days at the bottom of the page The second row of boxes will be for entering rainfall and irrigation amounts after the fields have been setup 5 leks Water for Lee Field 12 1 Soybean pana sear Figure 11 Detail page with water debits and credits for single field in past seven days When soil water deficit values equals 70 of the MAD level the Dryness Index column will display a single red asterisk Without rain or irrigation more asterisks will appear in the following days Avoid letting the index become red with XXX for several days Once a field soil becomes dry crop yield is lost W
11. of Missouri give no warranty as to the accuracy reliably uty or completeness of this information While we use care To provide accurate Wealher clmatic information errors may oceur because fof equipment or other failure Users o this weather climate data do so at their own risk and ate advised to use independent judgment as to whether to verly the data presented The University of Missouri expressly disclaims all warranties express and implied including but not Imite to the implied warranty at merchantability and finess for a particular purpose
12. riod for rainfall at the National Weather Service is not midnight to midnight It is mid morning to mid morning so a late afternoon rainfall still will not been posted in the app at 6 am the next morning If you know how much it rained in your rain gauge enter it rather than wait for an NWS update When NWS shows a rainfall amount but none actually occurred enter 0 in the blue Field Precip column When other fields on the farm also received the same amount of rainfall or none click the check boxes beside their names at the bottom of the page Field Precipitation C vomema Figure 13 Irrigation input page for entering irrigation events for fields To access a report for printing go to Report 3 row right column in the Main menu Figure 4 Select the field to print and click Print Figure 14 Figure 14 Example field reports showing daily rainfall irrigations and ET crop NWS Rainfall and ET Accuracy The greatest differences between NWS rainfall estimates and field rain gauge measurements usually occurs during isolated storms Figure 15 The NWS grid is too coarse to accurately estimate rainfall in small thunderstorms When heavy rainfall occurs on a field the soil water deficit balance reaches field capacity and soil water deficit becomes zero In this case a small inaccuracy is not critical in the app Figure 15 Rainfall tracked by National Weather Service radar If you clicked Yes in th
Download Pdf Manuals
Related Search