K-State Research and Extension News
March 18, 2014
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Online Tool Can Help with Efficient Crop Irrigation, Plus Projects Net Returns


K-State’s Crop Water Allocator can integrate several scenarios into one.

GARDEN CITY, Kan. – Its name is as straightforward as it comes. The Crop Water Allocator developed by Kansas State University has a simple name but can help producers navigate complex decisions regarding crops and rotations that best utilize water based on net economic returns. And using scarce water to help grow the global food supply is of utmost importance on the High Plains.

The CWA is one of several web-based and downloadable tools developed for crop producers by K-State Research and Extension agricultural engineers, economists and agronomists, available online at Crop Water Allocator

By going online and filling in such information as field size, soil type, annual rainfall, plus irrigation information, a farmer can use the CWA as a seasonal planning tool to find the optimum net return from combinations of crops, irrigation amounts, and land allocations that he or she wants to examine. CWA uses crop budgets, which can be customized using an individual farmer’s values or updated from the AgManager website, to compute the net return. If program users are unsure of some of the values to input, the tool offers a default feature, which estimates values such as irrigation information, crop prices and yields, and production costs.

“This tool not only allows the producer to allocate the irrigation water over the field, but also to look at the end of the season and compute the net return,” said Jonathan Aguilar, K-State Research and Extension water resource engineer. 

“Often a producer will get information through tools from irrigation company A, agrochemical company B and seed company C, but they would only allow you to see the benefit in terms of yield from that particular company’s input. The CWA will get you through the net returns combining the inputs from companies A, B and C,” said Aguilar in describing how the CWA integrates several scenarios into one.

By changing up the information, the tool is capable of evaluating an array of crop rotations and water allocations.

A practice scenario, for example, is if the price of corn is $6.50 per bushel and available water for irrigation is 11 inches, at what price will alfalfa and sunflower break even with corn? Under that scenario and using current default values, said Aguilar, the CWA found that alfalfa at $170 per ton and sunflower at $0.35 per pound, would break even with corn.

Drought management is another application of CWA, said Aguilar, who is based at K-State’s Southwest Research-Extension Center in Garden City: “Since you can specify in the CWA different annual precipitation levels, you could use a lower value for the precipitation to simulate drought and run the CWA to see what management strategy farmers could use.” 

Aguilar spoke earlier this year at a workshop in Garden City organized by the National Drought Mitigation Center. His recorded presentation is available online.

Other resources available at the Mobile Irrigation Lab are the Crop Yield Predictor, an in-season planning tool and KanSched, a daily decision tool to help monitor the root zone soil profile water balance using evapotranspiration (ET) data. ET-based irrigation scheduling can help producers determine when and how much irrigation water to apply.

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K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by: Mary Lou Peter
mlpeter@ksu.edu
K-State Research & Extension News

Jonathan Aguilar – 620-275-9164 or jaguilar@ksu.edu