控释氮肥适量减施对玉米产量和氮素利用效率的影响

通过连续两年田间试验，研究控释氮肥较农民习惯用量减施对玉米产量与产量构成因素、氮素吸收利用的影响。试验设5个处理，分别为不施氮肥(N0)、农民习惯施氮(FP)、80%控释氮肥(CRU1)、70%控释氮肥(CRU2)、60%控释氮肥(CRU3)。结果表明，与FP处理相比，CRU1和CRU2处理显著提高了玉米产量(P<0.05)，两年平均产量分别提高7.0%和5.4%。CRU1、CRU2处理两年平均玉米氮素最大积累速率和平均积累速率较FP处理分别提高9.6%、6.5%和7.9%、6.2%，玉米氮素最大增长速率出现天数分别提前7.2 d、5.0 d。与FP处理相比，控释氮肥减量施用处理显著提高了氮素回收率、农学利用率和偏生产力(P<0.05)，其中，氮素回收率和偏生产力随控释氮肥减施比例的增加显著增加，氮素农学利用率表现为先增后降，以CRU2处理最高。控释氮肥减量30%(193 kg/hm2)可实现玉米产量和氮素利用率同步提高。

Reducing Application of Controlled-release Nitrogen Fertilizer to Improve Maize Yield and Nitrogen Utilization Rate

Two-year field experiment was conducted to investigate the effects of reduced application of controlled-release N fertilizer(CRU) compared with farmer conventional fertilization on maize yield, its components, N absorption and utilization. The experiment was set up five treatments, including no N fertilizer(N0), farmer conventional fertilization(FP), 80% CRU(CRU1), 70% CRU(CRU2), and 60% CRU(CRU3). The results showed that CRU1 and CRU2 treatments increased significantly maize yield(P<0.05) than FP treatment. The two-year average yield increased by 7.0% and 5.4%, respectively. The maximum and average N accumulation rates of maize under CRU1 and CRU2 treatments were increased by 9.6%, 6.5% and 7.9%, 6.2% than FP treatment, and the days of maximum N increase rate appeared 7.2 d and 5.0 d earlier, respectively. Compared with FP treatment, reduced application of CRU significantly improved REN, AEN, and PFPN(P<0.05). REN and PFPN significantly increased with increasing of the reduction ratio of CRU. While AEN increased at first and decreased later, and the highest value was found under CRU2 treatment. 30% reduction of CRU(193 kg/ha) can achieve simultaneous improvement of maize yield and N use efficiency in this condition.