When Should You Turn Off the Water?

Whether you grow corn or cotton, the last pass of your pivot is just as important as the first. 

“If you stop irrigating too soon and stress the crop before it reaches maturity, yields will be negatively impacted,” said Tim Wilson, irrigation engineering manager at Lindsay Corporation. “On the other hand, watering longer than you really need to adds unnecessary expenses, reduces profits and can leave the field wetter than desired come harvest time.” 

So, how do you know when it’s time to stop irrigating?

There’s no hard and fast date, so Wilson advises growers to monitor soil moisture and check the crop growth stage. For growers who don’t want to rely solely on visual inspections of their fields and complex calculations, he recommends FieldNET Advisor™– advanced technology that helps growers make critical irrigation decisions.

Backed by more than 40 years of crop and irrigation science, FieldNET Advisor provides growers with field-specific and crop-specific irrigation recommendations. The daily recommendations are optimized to help growers avoid water stress throughout the season – including information that can help them use even less water at the end of the growing season.

“Using FieldNET Advisor’s unique forecasted yield loss (see red highlighted yield loss section in the image above), growers have the data they need to decide when it’s economically optimal to stop irrigating,” said Kurtis Charling, manager of FieldNET Business Solutions at Lindsay Corporation. “This forecasted yield loss is an estimate of the percentage of the crop’s yield potential that will be lost if no additional irrigation is applied through the remainder of the season. With this information, a grower may decide to reduce the final irrigation amount or stop irrigating altogether to let the crop further deplete the soil water – particularly if the yield loss is minimal or if the value of the projected yield loss, without additional irrigation, is less than the cost of applied irrigation.”

Charling added that the red outline in the illustration highlights the graphical view of FieldNET Advisor’s projected irrigation schedule, which growers can use to help confirm their decision to reduce or suspend irrigations at the end of the season. The chart displays the season-to-date soil water depletion and irrigation history. It also shows the forecasted soil water depletion and irrigation recommendations through the remainder of the growing season based on the field-specific hourly weather forecast out 15 days in the future and field-specific historical norms beyond the 15 day forecast.  

“With FieldNET Advisor, growers can be extremely confident, knowing their decisions are based on recognized practices for irrigation scheduling,” Charling said. 

For more information about FieldNET Advisor, talk to your local Zimmatic dealer or visit www.fieldnetadvisor.com.