Controlled Release Urea Improved Nitrogen Use Efficiency, Yield, and Quality of Wheat

Abstract

The effects of newly developed controlled release urea (CRU) and its placement method on the N use efficiency and nutritional quality of winter wheat (Triticum aestivum L.) grown on a loam soil were investigated during 2 yr. The winter wheat was grown on a loam soil. The CRU was applied at 0, 75, 150, and 225 kg N ha−1 and the urea was applied at 225 kg N ha−1 The CRU was applied with wheat seeds during sowing while the urea treatment was split into two applications: two‐thirds applied during sowing and one‐third at the 5‐tiller stage (Z25). Results showed that N release rates of CRU fit N requirements of wheat and the placement of wheat seeds with CRU improved wheat's apparent N uptake efficiency by 28.5% compared to urea treatment. Although the CRU treatment at 150 kg N ha−1 had one‐third less supplied N than that of conventional urea treatment (225 kg N ha−1), the wheat with CRU at 150 kg N ha−1 produced 6.5% more grain. In addition, at the same or one‐third reduced amount of N compared with the conventional urea treatment, CRU significantly increased the contents of Fe and Mn, providing additional nutrition and quality to the wheat grain.