Long-Term Effects of Controlled-Release Urea on Crop Yields and Soil Fertility under Wheat–Corn Double Cropping Systems
2016
Zheng, Wenkui | Sui, Changling | Liu, Zhiguang | Geng, Jibiao | Tian, Xiaofei | Yang, Xiuyi | Li, Chengliang | Zhang, Min
The long-term effects of controlled-release urea (CRU) on crop yields and soil properties were investigated in lysimeters under wheat and corn rotation system from 2009 to 2014 in northern China. The CRU included polymer-coated urea (PCU), sulfur-coated urea (SCU), and polymer coating of sulfur-coated urea (PSCU) was applied at 147, 210 kg N ha–¹ for wheat and 262.5, 375 kg N ha–¹ for corn and the urea was applied at 210 kg N ha–¹ for wheat and 375 kg N ha–¹ for corn. Results showed that the N release characteristics of three kinds of CRU in field condition were all closely matched to the N requirement of crops. Consequently, the CRU treatments improved wheat and corn yields by 3.2 to 10.1% and 4.9 to 11.1%, increased apparent N use efficiency by 45.9 to 53.8% in wheat, and 36.2 to 45.4% in corn, respectively, compared with urea. Furthermore, the PSCU achieved the highest and the most stable crop yields among CRU. Even reducing CRU rate by 30% produced the same yields as with the 100% rate of urea. In addition, soil total N and organic matter contents in CRU were effectively increased in the topsoil of 0 to 20 cm after 5 yr. Therefore, long-term application of CRU had great potential to increase wheat–corn yields, N use efficiency, reduce application frequency, improve soil fertility, decrease the leaching of soil NO₃––N and NH₄⁺–N, and also relieve soil pH decreased.
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