Predicting when and how much to water fields is especially difficult when weather conditions trend to the extreme. University of Wisconsin-Madison research is yielding technologies that help farmers fine-tune irrigation to save water and the energy needed to pump it. An online tool called WISP 2012, developed by UW-Madison soil and water conservation specialists, makes it easier to make better decisions about when and how much to water.
"Having adequate water in the root zone is critical to good yields and high quality crops," says John Panuska, a UW-Madison soil and water conservation specialist. But too much water can wash nutrients and pesticides out of the root zone and into groundwater and streams. Excess water is a three-strike proposition—higher costs for nutrient application, higher costs for pumping, and possible contamination of water needed by people and wildlife.
How can a farmer decide how much water to apply? It's more complicated than in the home garden, where you can simply feel the soil surface and look for wilted leaves. When a field is running a water deficit at key stages in crop growth, a farmer may need to play catch-up by irrigating even in the midst of a rainstorm.
"When you're driving down the road and you see irrigation systems running a lot, you think they're wasting water," says Panuska. "But pumping water costs money and they're not going to want to waste that water."
Avoiding that waste has become easier thanks to the Wisconsin Irrigation Scheduling Program, or WISP 2012. This online tool offers growers a lot of flexibility. They can enter key information— the type of crop, soil type and rainfall—from the field via smart phones or tablets. WISP 2012 uses that information to make a recommendation on when to irrigate.
Growers will be able to use WISP technology to save even more water as crop scientists uncover new water-conserving strategies. For example Nebraska researchers have found that soybeans can go through much of their early life without any irrigation, and UW-Madison's A.J. Bussan is trying to find out if the same is true for corn. If those ideas pan out, farmers could use WISP 2012 to adjust their irrigation accordingly. And if a grower wants to irrigate a little less to leave some "room" in the soil for rain, WISP 2012 can help with the fine tuning.