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Optimize Your Irrigation Application Timing with SoyWater

Optimize Your Irrigation Application Timing with SoyWater


Get the most from your irrigations with SoyWater, an easy to use, irrigation management tool.  It provides timely crop water use information specific to your field and this year’s growing conditions. It is available on the Web at www.soywater.unl.edu or simply Google™ the words “UNL SoyWater.”

This decision support tool was developed by the University of Nebraska-Lincoln with support from soybean checkoff funds provided by the Nebraska Soybean Board. Unlike many other management tools, SoyWater doesn't require you to install anything on your home computer or spend time learning a new software program.  It guides you through four simple steps to input information so you can get field-specific irrigation recommendations.

SoyWater can help you determine how much water your field needs and when it needs it, eliminating unnecessary irrigation events. An acre-inch of water applied is equivalent to 27,154 gallons of water. Thus, saving one unnecessary one-inch irrigation event could save you 5,424,800 gallons of water on a 200-acre pivot. Moreover, you would also save pumping energy cost and time. Such savings would allow you to optimize your input use efficiency (bushels per acre per inch of water applied or energy used).

Even if you don’t irrigate, SoyWater can help you fine-tune your management. Both rainfed and irrigated producers can use it to track and predict the dates when a field will reach a specific soybean stage. Pest control and disease management are much more effective if the pesticide or fungicide is applied precisely at the soybean stage that researchers recommend.

About 266 users have registered to use SoyWater since its official launch on May 1, 2010. We invite you to join this group and learn how to more effectively schedule soybean irrigation events to apply just the right amount at just the right time.


Figure 1. A SoyWater crop water use table generated in 2010.


Figure 2. Chart of data developed using SoyWater. Note that these figures show the user irrigating on precisely the dates recommended by SoyWater, applying just the right amount of water at just the right time.

Estimating Growth Stages


SoyWater uses a crop model (SoySim) to create a table showing the calendar date for each soybean vegetative and reproductive stage from emergence to maturity with corresponding and daily and cumulative soybean crop water use values specific to your field.

Once your account is established, you can log into it any time to view the updated information as the crop season progresses. As irrigation or rain events occur, you will need to input the date and amount of water applied or rain measured at the site. SoyWater estimates the first and subsequent dates when irrigation should be applied and soil water depletion amount on those dates is highlighted in yellow in the SoyWater table for that field. This recommendation is based on the soil water depletion percentage value (default is 35%) that you choose as an “irrigation trigger.”

Source: University of Nebraska–Lincoln