缓释尿素在玉米上的应用效果

Effects of Slow-release Urea on Maize Yield

利用大田小区试验,在赤峰市和鄂尔多斯市分别进行不同氮素处理对玉米产量、肥料吸收利用和土壤氮残留影响的研究。结果表明,施用氮肥玉米子粒产量和秸秆产量可分别增加13.3%～157.2%和6.9%～64.2%。减少20%施氮量同时配比75%的缓释尿素处理,玉米子粒氮含量、秸秆氮含量和氮积累量最大,与100%推荐施氮量无显著差异。缓释尿素占比60%以上时氮素回收率、氮肥偏生产力和氮肥农学效率达最大值,较普通尿素（RU）可分别提高14.3、4.5、61.7个百分点（赤峰市）和8.4、11.0、35.7个百分点（鄂尔多斯市）。玉米收获后耕层（0～20 cm）土壤矿质氮含量表现,赤峰市耕层土壤硝态氮含量远大于铵态氮且不同处理间差异显著（P〈0.05）,100%推荐施氮量最大,80%推荐施氮量（RU80%）最小。鄂尔多斯市耕层土壤硝态氮含量和铵态氮含量基本相当,除各氮素处理与对照（CK）达显著差异外（P〈0.05）,其他各处理间均未达显著差异。施氮量减少20%,缓释尿素占比30%以上与普通尿素配施即可替代100%推荐施氮量,且缓释尿素占比越大养分吸收利用越显著,玉米产量间无显著差异。

To explore the effects of slow-release urea（CRU） on maize, seven treatments, control（CK, no urea application）, 100% normal urea（RU）, 80% RU, 25% RU＋75% CRU, 40% RU＋60% CRU, 55% RU＋45% CRU, and70% RU＋30% CRU, were performed respectively in Chifeng and Ordos cities of Inner Mongolia, China. Results indicated that grain and straw yields of maize applied urea were increased by 13.3%-157.2% and 6.9%-64.2%, respectively, when compared with that of CK, and among CRU treatments, the maize in the treatment of 25% RU＋75% CRU got the highest yieldwhich was the same as that in 100% RU. In the treatments of 25% RU＋75% CRU and 40% RU＋60% CRU, N utilization efficiency, partial factor productivity of applied N（PFPN）, and N agronomy efficiency were up to the maximum values, which were more than that in 100% RU by 14.3, 4.5, 61.7% in Chifeng and by 8.4, 11.0, 35.7% in Ordos, respectively. After harvest, N contents in the soil top layer（0-20 cm） of different treatments were significantly different at the location of Chifeng, and the maximum（26.16 mg/kg） and minimum（18.37 mg/kg） values were got in 100% RU and 80% RU treatments, respectively. In addition, NO3^--N contents were 3.5-7.0 times of NH4~＋-N While, NO3^--N and NH4~＋-N contents in the soil top layer were nearly the same（1.85-3.26 mg/kg） among the treatments in Ordos, except that of CK was significantly different from others. In summary,CRU was benefit for maize production, and 20% of the recommended N application amount would be saved when more than 30% of the total N application was replaced by CRU.