Effects of Fertilization on Yield and Nitrogen Use Efficiency of Wheat and Rice with Straw Return

Abstract

ABSTRACT Fertilizer application of controlled-release urea (CRU) is a feasible fertilization method because of its simple operation, high efficiency, environmental friendliness, and labor-saving. However, the high cost of CRU and the dynamic change of nitrogen (N) demand caused by straw return make it necessary to find a better fertilization method. Therefore, we investigated the effects of application of the mixed CRU and urea on the yield and nitrogen use efficiency (NUE) of wheat and rice, and soil fertility with straw return. The results indicated that application of the mixed CRU and urea increased the yield of wheat and rice compared with 100% urea application. The maximum increments of yield of wheat and rice occurred in the substitution ratio of CRU with 50%. Reducing N application rate of the mixed CRU and urea in wheat by 20% and rice by 15% also increased the yield of wheat and rice compared with 100% urea. Applying the mixed CRU and urea increased NUE of wheat and rice, compared with 100% urea. The maximum increments of NUE of wheat and rice were 31.9% and 37.4%, respectively. Reducing N application rate of the mixed CRU and urea could further increase NUE of wheat and rice. Compared with 100% urea, applying the mixed CRU and urea increased soil organic carbon, total N, alkaline N, and urease concentration. In summary, application of the mixed CRU and urea is feasible to achieve stable crop yield and to improve NUE with straw return. In addition, the application of CRU requires less N fertilizer application. Therefore, application of mixed CRU and urea is of great significance to ensure national food security and sustainable agricultural development.