How to Develop an Irrigation Schedule Using Cropwat 8.

Step-by-Step Guide

1. 1

   Step 1: Download and install the software.

   Download CropWat
   8.0 from FAO website and then install it.
   
   This program runs on the following Windows platforms: 95/98/ME/2000/NT/XP/7 and Vista.
   
   To get the software, visit http://www.fao.org/nr/water/infores_databases_cropwat.html.
2. 2

   Step 2: Get familiar with the user interface.

   CropWat
   8.0 has a user friendly interface that includes the following features:
   Using the ‘File’ menu, you can start a new session, open an existing session, save a session, close a session, open new input file (climate/ETo, Rain, crop, soil and cropping pattern), save a input or output file, print and exit.
   
   From the ‘Edit’ menu you can do basic cut, copy and paste operations.
   
   From the ‘Calculations’ menu you can calculate water requirements, develop schedule and calculate scheme supply.
   
   The buttons on the left side panel can also be used to create input files or perform calculations.
   
   Using the ‘Charts’ menu, you can create charts or graphs.
   
   Using the ‘Settings’ menu, you can change options of input and output files and change file locations.
   
   From the ‘Language’ menu, you can change the interface to either English, French, Russian or Spanish languages. , Click on the ‘Climate/ETo’ button on left side panel to input the collected climate data.
   
   CropWat uses daily, decade or monthly climate data to estimate reference evapotranspiration (ETo).
   
   If you want to calculate irrigation water requirements for any previous year, then you need to collect the climate data for that year from your nearest meteorological station.
   
   If you want to calculate irrigation water requirements for any future time then you need to collect future forecast data.
   
   If local climatic data are not available, you can obtain those data for over 5,000 stations worldwide from CLIMWAT (an associated climatic database). , CropWat requires the following climate data: maximum and minimum temperature (°C) or average temperature (°C), relative humidity (%) or vapour pressure (kPa), wind speed (km/day or m/s), sunshine hour or percent of day length or fraction of day length. , Collect the rainfall data.
   
   Click on the ‘Rain’ button to input the collected rainfall data. , The available options for calculating effective rainfall are: fixed percentage, dependable rainfall (FAO/AGLW formula), empirical formula, and USDA soil conservation service method. , Collect the required crop data.
   
   Click on the ‘Crop’ button on the left side panel to input the crop data.
   
   CropWat is suitable to estimate irrigation water requirements for both dry crops and rice. ,,, Collect the required soil data.
   
   Click on the ‘Soil’ button on the left side panel to input the soil data.
   
   CropWat requires the following soil data: total available soil moisture (mm/meter), maximum rain infiltration rate (mm/day), maximum rooting depth (cm), initial soil moisture depletion (as % TAM), initial available soil moisture (mm/meter). , or % depl.), maximum water depth (mm). , After completing the previous steps, click on the ‘CWR’ button on the left side panel to estimate your own irrigation water requirements.
   
   Irrigation requirements are showed in mm/decade. , Click on the ‘Charts’ menu, then click on ‘Climate/ETo/Rain’ to get a chart of the inputted climate variables.
   
   Below the chart you will see that there are options to select which variables you want to show on your chart.
   
   You can also select whether the variables will show as either a bar or a curve. , Click on the ‘Charts’ menu, then click on ‘Crop Water Requirements’ to get a graph of your crop water requirements.
   
   Within the same graph you can also get an ET crop by selecting the ‘ET crop’ option below the graph.
   
   You can also select whether those will show either as a bar or a curve. , By clicking on the 'Schedule' button, you will get a table of irrigation schedule and a table of daily soil moisture balance.
   
   You will get information on: total gross irrigation, total net irrigation, total irrigation losses, total percolation losses, actual water use by crop, potential water use by crop, effective rainfall, total rain loss, moist deficit at harvest, actual irrigation requirement, and yield reduction. , The available irrigation timing options are: irrigation at fixed water depth, irrigation at fixed % desaturation, irrigation at fixed % of critical depletion, irrigation at fixed WD/desaturation/critical depletion per stage, irrigation at fixed interval per stage, irrigation at given ET crop reduction, irrigation at given yield reduction, irrigate continuously, no irrigation (rain-fed). , These include: user defined application depth, refill to fixed water depth, refill to or below saturation, refill to or below field capacity, refill to fixed WD/saturation/FC, fixed application depth. , Click on the ‘Charts’ menu, then click on ‘Irrigation Schedule’ to get a graph of your irrigation schedule.
   
   Below the graph you can select options (for example, depletion soil moisture, depletion saturated water, RAM root zone, TAM root zone, SAT root zone, TAM whole puddle and SAT whole puddle), which you can either show or hide in the graph.
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   Step 3: Collect and input climate data.

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   Step 4: Get the appropriate data.

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   Step 5: Collect and input rainfall data.

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   Step 6: From the ‘Settings’ menu open the ‘Options’ and click on ‘Rainfall’ tab to select the method of calculating effective rainfall.

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   Step 7: Collect and input crop data.

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   Step 8: Collect the following crop data for dry crops: planting date

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   Step 9: Kc values at initial

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    Step 10: mid-season and at harvest

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    Step 11: number of days for initial

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    Step 12: development

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    Step 13: mid-season and late season

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    Step 14: rooting depth (m)

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    Step 15: critical depletion (fraction) at initial

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    Step 16: mid-season and late season

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    Step 17: yield response factor at initial

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    Step 18: development

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    Step 19: mid-season and late season

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    Step 20: crop height (m).

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    Step 21: Collect the following data for rice (you need to collect some additional data): both Kc dry and Kc wet values at every stage

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    Step 22: number of days for nursery and land preparation also

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    Step 23: puddling depth (m)

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    Step 24: nursery area (%).

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    Step 25: Collect and input soil data.

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    Step 26: Provide additional soil data for rice: drainable porosity (%)

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    Step 27: critical depletion for puddle cracking (fraction)

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    Step 28: maximum percolation rate after puddling (mm/day)

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    Step 29: water availability at planting (mm WD or % desat.

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    Step 30: Estimate your irrigation water requirements.

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    Step 31: Get a climate/ETo/rain chart.

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    Step 32: Get a crop water requirements graph.

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    Step 33: Click on the ‘Schedule’ button on the left side panel to get a tailored irrigation schedule.

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    Step 34: Click on the ‘Options’ button to modify the scheduling based on different irrigation timing

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    Step 35: irrigation application system and irrigation efficiency.

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    Step 36: Check the other available irrigation application options to see if these are needed too.

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    Step 37: Get an irrigation schedule graph.

Detailed Guide

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