On‐farm evaluations of overhead irrigation sprinkler packages at full and reduced rates

Abstract

Irrigation is a critical resource in meeting the global demand for food, feed, fiber, and fuel. One water optimization method with high potential and interest is the use of more efficient irrigation systems. In many areas where pivots are used, the most common sprinkler package is mid‐elevation sprinkler application (MESA), which typically has application efficiencies near 80%. Low‐energy precision application (LEPA) and mobile drip irrigation (MDI) can have greater than 95% application efficiency. The objective of this research was to evaluate the ability of LEPA and MDI to maintain crop yield and quality in alfalfa (Medicago sativa L.) and silage corn (Zea mays L.), at similar and reduced irrigation rates as MESA. The intent of the reduced rate was to determine if the decreased application losses with LEPA and MDI could result in sustained crop production with a 20% irrigation rate reduction. Actual reductions ranged from 5% to 55% depending on system and site due to equipment constraints. Data from two farms in Utah during 2018–2020 provided evidence that these systems can often maintain yield and forage quality with 5%–55% less applied water. However, there were also many instances where yield was reduced by LEPA and MDI, even with similar application rates to MESA. This indicates that the two higher efficiency systems will not save water in all cases and that the application system must be carefully evaluated in small on‐farm trials over multiple years for its ability to succeed in specific field conditions.