Controlled Release Urea Improved Nitrogen Use Efficiency and Yield of Wheat and Corn

Nitrogen fertilizer is important for improving wheat ( Triticum aestivum L.) and corn ( Zea mays L.) yields, but inappropriate application methods and excessive amounts lead to low N use efficiency and high N losses through leaching. To investigate the effects of controlled‐release urea (CRU) on crop yield and soil fertility, a field experiment was conducted from 2012 to 2014 in China. The 100% (180 kg ha −1 ) and 70% (126 kg ha −1 ) of the local practice N rates with CRU and urea were used. The results revealed that the release curves of CRU in the natural field corresponded well to the N requirements of wheat and corn plants, and a positive linear correlation was observed between release rates and days after buried in soil. Consequently, the CRU treatments achieved significantly higher wheat and corn yield by 8 to 12% and 9 to 11%, respectively, compared with urea treatments at the same N rate. Reducing N rate of CRU by 30% produced the same yield as with the 100% N rate of urea. The agronomic nitrogen use efficiency (NUE) was significantly increased and the leaching of soil N was reduced by CRU. The acidification rates and leaching of exchangeable Ca 2+ , K + , Na + contents were reduced, base saturation and available P improved by application of CRU compared with urea. Therefore, the results suggested that a 30% decrease of CRU in the recommended application rate of N, can be an effective measure to save consumption input of N fertilizer. Core Ideas Nitrogen release rates of controlled‐release urea in field condition corresponded well to the N uptake of crop plants. A 30% decrease in the application rate of N is possible with controlled‐release urea compared to urea. The application of controlled‐release urea increased crop yield, N use efficiency, net farm profit, and soil fertility.