Study: High crop yields compatible with irrigation estimates

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Study: High crop yields compatible with irrigation estimates

About a third of producer fields studied were successful in achieving high yields within irrigated water requirements.
About a third of producer fields studied were successful in achieving high yields within irrigated water requirements.

New research from University of Nebraska researchers has found that one-third of studied fields achieved high crop yields without surpassing prescribed irrigation levels.

The study shows that it’s possible to nearly maximize yields while adhering to the estimated amounts of irrigation needed to support those yields, the researchers said. Reaching even 80% of potential yields is considered a reasonable goal for U.S. corn, the team said.

Conducted by researchers from the Daugherty Water for Food Global Institute and the University of Nebraska-Lincoln, the study collected data from so-called Natural Resources Districts and via producer surveys. Whereas previous studies relied primarily on data from simulations or research farms, the new study used producer data from more than 500 corn and soybean fields in Nebraska. The researchers then developed a framework to diagnose current irrigation water use in relation to grain production in producer fields.

The team also found that yields did not substantially vary among fields that used different types of irrigation scheduling. One type relied on the technology-intensive measurement of factors such as water balances and soil moisture; another entailed simple visual assessments of plant status; and a third involved rudimentary methods such as fixed calendar dates or following a neighbor’s schedule.

However, fields that used the technology-intensive approach did better adhere to suggested irrigation limits. Those fields represented just 22% of the total studied, indicating ample opportunity to save irrigation water and potentially increase farm profits by adopting newer technologies, the team said.

Actual irrigation was similar to estimated irrigation requirements in more than half of the fields, suggesting that many producers are using their available irrigation wisely, said lead author Kate Gibson, a project manager with the Water for Food Institute. But the remaining proportion could still save a substantial amount of water.

“Potential irrigation water savings are greatest in years with above- or near-average precipitation,” said co-author Patricio Grassini, associate professor of agronomy and horticulture.

Justin Gibson, a postdoctoral researcher with the Water for Food Institute, said that flexible irrigation equipment could help ensure the timely and precise delivery of water. This could also reduce unnecessary water use by excess irrigation, which can adversely affect water quality, contribute to greenhouse gas emissions and burden agricultural producers with unneeded costs, he said.

The team reported its finding in the journal Environmental Research Letters. Funding came from the Water for Food Institute, the Nebraska Corn Board and the Nebraska Soybean Board.