Evaluation of nitrogen fertilizer source and application method for dryland wheat

Abstract

Optimizing nitrogen (N) fertilization is critical to ensure high-yield and high-quality wheat (Triticum aestivum L.) production while minimizing its environmental footprint and production costs. A two-yr field trial was conducted in a dryland research farm in Montana with a clay loam soil to evaluate the response of spring bread wheat (cv. Velva) and durum (Triticum durum Defs cv. Joppa) to N rate (45 vs. 90 kg ha−1), N source (urea vs. SuperU®), and application method (broadcast vs. banding). Compared to broadcast application, fertilizer banding reduced plant density by 6% without affecting the final grain yield. Nitrogen rate had a significant effect on grain yield. Neither nitrogen source nor application method affected grain yield when N was applied at 90 kg N ha−1. Grain yield increased from 3171 to 3652 kg ha−1 with increasing N rate from 45 to 90 kg ha−1 in the year with ample rainfall, whereas yield remained unchanged in the drier year. Protein concentration was higher in broadcasting treatment compared to banding at 90 kg N ha−1. However, at 45 kg N ha−1, protein concentration in the grain was not affected by method of application. The source of fertilizer did not show a significant effect on grain protein concentration. Our data indicated no agronomic benefit in using SuperU compared to conventional urea or banding fertilizer vs. broadcasting in this dryland system.