Kansas State University agricultural engineers have taken another step toward removing the guesswork from crop irrigation scheduling. The result could mean greater yields, reduced water and energy usage and possibly more time for the producer.

KanSched2, an updated release of a computer software program that uses evapotranspiration (ET) data, is designed to help monitor root zone water in the soil. That can help a producer schedule irrigation events, says Dan Rogers, agricultural engineer with K-State Research and Extension. The program can also be used to monitor the soil profile water content of non-irrigated fields.

Information about KanSched2 can be found on K-State Research and Extension Mobile Irrigation Lab Web site at http://www.oznet.ksu.edu/mil. There is no charge for the software.

"ET-based irrigation scheduling is a tool that can help you determine when and how much irrigation water to apply," says Rogers, who along with Mahbub Alum of K-State’s Southwest Area Research and Extension Center in Garden City, developed KanSched2. The software is an updated and expanded version of its predecessor, KanSched 1.0. "The basic process involves using data on crop water use, rainfall, and soil water storage to assess when an irrigation event is needed and how much water could be applied."

New features built into the program include a way to account for cutting cycles in alfalfa, an irrigation forecast (five days into the future), irrigation fuel cost accounting and a water record page for individual fields. Pull-down menus are incorporated throughout the program.

"Those who have used the original KanSched are likely to find KanSched2 familiar and should have little or no difficulty adapting," Rogers says. "Plus, once a season has ended or a new season is ready for new data entry, the previous season data can be saved and new season data for the same field can begin without having to create a new field or delete the old data."

Irrigation scheduling that uses ET information is much like using checkbook accounting where valued commodities are tracked, Rogers explains. In this case soil water, rather than money, is the valued commodity. The debit is crop water use, while the credits are rainfall and irrigation.

One notable difference, however, is that the water balance can be in excess as well as deficient. Crop evapotranspiration is the amount of water that a crop withdraws from the soil water reserve in its root zone.

"The major goal of the ‘accounting procedure’ is to help the producer keep the amount of water in reserve above a minimum acceptable soil water balance level to prevent water stress to the growing crop," Rogers says.

“The benefits of irrigation scheduling generally translate into increased net returns through several avenues. Most irrigated areas of the state are experiencing declining water levels or increased competition for existing water resources from other types of water users. Irrigation scheduling allows irrigators to document their use of water relative to the crops demand. Matching water needs should also minimize irrigation pumping cost, since no excess water is applied, and may also boost yields due to less water stress or less loss of fertilizer due to leaching.”