Exploring winter barley phosphorus and nitrogen needs in western Nebraska

Abstract

Cropping systems in the U.S. High Plains are primarily limited by water availability and a shortened growing season due to the region's high elevations. Winter barley ( Hordeum vulgare L.) shares similar agronomic requirements and equipment needs with winter wheat, and Nebraska's large cattle industry provides an established market for barley as feed or grazing, supporting its adoption with minimal infrastructure changes. Experiments were conducted from 2021 to 2024 at two locations in western Nebraska. The experiments focused on optimizing the timing, rates, and types of P and N fertilizers for grain yield to optimize barley grain yield in the High Plains region. Grain yield was 35% higher than the control when applying 60 lb ac ⁻¹ of P and 18 lb ac ⁻¹ of N as monoammonium phosphate (MAP) and urea, especially when combined with spring N topdress (32 lb ac ⁻¹ of N), which resulted in a 43% yield advantage over the control treatment. Nitrogen‐only applications increased grain protein content by 6.5% compared with combined P and N split applications. When N was applied 100% in‐furrow, grain protein content increased by 7.5% compared with split application. Tillering, total aerial biomass, and plant height were 24%, 38%, and 5% higher, respectively, in the P+N treatment compared with the N‐only treatment. Overall, these results suggest that P placement, combined with split N management, plays a key role in optimizing winter barley yield in western Nebraska. This also suggests that, in the short term, the P source matters, with MAP outperforming 40 Rock, although the physiological or agronomic basis for this advantage warrants further investigation.