Irrigation scheduling application to conserve water resources

Agriculture today is not what it was a decade ago. We are at an interesting pace of agricultural technological innovation and development in sensors, controls, robotics and technology, including irrigation scheduling applications. The declining quantity and quality of freshwater resources in many parts of the world, including the United States, imposes significant challenges for producers, managers, advisors and decision-makers to produce more yield with less water. It is necessary to promote sound management strategies to improve irrigation efficiency and conserve water resources. By using irrigation scheduling applications, producers can make more informed decisions that can lead to higher yields with fewer irrigation inputs.

Nebraska is one of the top states that produces maize under different irrigation methods, in third place after Iowa and Illinois. The total irrigated area in Nebraska reaches about 9.3 million acres. More than 85% of the total irrigation areas use the center pivot irrigation system, while about 15% is covered by furrow irrigation and less than 1% is managed by subsurface drip irrigation systems (see fig. 1).

A new irrigation scheduling application is being developed to improve irrigation scheduling that can have a substantial impact in using limited water supplies more effectively and increase yield per unit applied of irrigation water and sustain agricultural productivity. At the request of Irriga Global, Lutry, Switzerland, a field test was initiated for the 2022 growing season on maize fields to evaluate the irrigation scheduling application in one of the University of Nebraska-Lincoln/Biological Systems Engineering research facilities at the Eastern Nebraska Research, Extension and Education Center.

Overall, the use of irrigation scheduling applications in limited water regions in semi-arid and arid climates has the potential to revolutionize the way of scheduling irrigation.

The performance and results were compared with other irrigation scheduling applications including third-party products and control irrigation scheduling. The test was established on about an 18-acre plot irrigated by a four-span center pivot system. A control panel and online interface were used to implement speed-control variable rate irrigation prescriptions to accommodate the different irrigation needs of the treatments. The field test included three irrigation treatments. First, the IrrigaNet section ran irrigation events based on the app’s recommendations. The control treatment was based on the recommendation from the Eastern Nebraska Research, Extension and Education Center farm staff and agronomist. Also, a third-party product was used for the remaining group, which irrigated based on its sensor recommendations. Each treatment was replicated three times.

Neutron probe access tubes were installed in all replications of each irrigation treatment to monitor soil water content in a 1.52-meter (5-foot) soil profile beginning June 7, 2022. Soil water readings were periodically recorded at the midpoint of each 12-inch increment throughout the growing season until mid-September 2022, using a neutron probe. A catch can uniformity test was performed on the system in mid-June 2022 to evaluate system performance before any irrigation applications occurred.

The maize under the IrrigaNet irrigation scheduling application received 80 mm (3.14 in.) and 53 mm (2.1 in.) less than the third-party product and control group, respectively (see fig. 2). The analyzed maize grain yield was similar across all irrigation scheduling applications (i.e., IrrigaNet and third-party product) and control irrigation scheduling indicated that there were no significant differences due to the irrigation scheduling (see fig. 3).

This application can have a considerable impact in using limited water supplies more effectively and increase yield per unit applied of irrigation water and sustain agricultural productivity.

Today, these technologies facilitate irrigation scheduling for producers more than was available a decade ago. Overall, the use of irrigation scheduling applications in limited-water regions in semi-arid and arid climates has the potential to revolutionize the way of scheduling irrigation. It can be used to optimize the utilization of water resources and predict the accurate amount and time of irrigation water that is required for crops. These applications can help producers make optimal irrigation decisions at the optimal time. As these applications continue to develop, they will likely be utilized increasingly commonly and will play a significant role in assisting producers to feed the world’s rapidly growing population.

Ali Mohammed, PhD, is a post-doctoral research associate of biological systems engineer-ing at the University of Nebraska–Lincoln.
Derek Heeren, PhD, PE, is an associate professor of biological systems engineering at the University of Nebraska–Lincoln.
Eric Wilkening is a graduate research assistant of biological systems engineering at the University of Nebraska–Lincoln.