摘 要 ：通过连续2a的大田试验，比较研究了尿素与包膜尿素对夏播玉米郑单958和农大108产量、水分利用效率(WUE)、氮肥利用率(NUE)与土壤无机氮动态的影响，结果表明：产量与WUE随施氮量增大而增大，两种氮肥间差异不显著；包膜尿素NUE较尿素高，2004年郑单958 N 90 kg/hm2与农大108 N 180 kg/hm2条件下提高显著；施氮对土壤无机氮动态的影响具有年际间差异：2004年不施氮条件下一般呈“V”型变化趋势，施氮使其向“N”型或倒“V”型转变，而2005年施氮与不施氮条件下均呈“N”型变化趋势；施氮使土壤无机氮含量明显提高，包膜尿素较尿素效果更明显；土壤无机氮含量，包膜尿素处理以表土层最高，而尿素处理，特别是尿素N 180 kg/hm2处理9叶展至吐丝期以下层土壤较高，2004年表现尤为明显。可见在降水量较多的年份，包膜尿素缓释效应明显，能有效控制无机氮的下移。华北平原夏玉米季以包膜尿素替代尿素、以一次性基施替代基肥＋追肥是完全可行的，能达到省工、增效、环保目的。
Abstract:A two-year field experiment was conducted to study the effects of two types of nitrogen fertilizers (urea; coated urea, CU) on maize yield, water use efficiency (WUE), nitrogen use efficiency (NUE) and dynamics of soil Nmin content (DSNC) in 2004 and 2005. Two summer maize cultivars, Zhengdan958 and ND108, were applied. The results showed that yield and WUE were increased by the increase of N input, but no significant difference was observed between urea and CU treatments. NUE of maize under CU treatment was higher than that under urea treatment, especially the diffefrence was significant under treatments of 90 kg N/hm2 (Zhengdan958) and 180 kg N/hm2 (ND108) in 2004. Effects of N application on DSNC showed annual difference. In 2004, DSNC showed “V” shape under zero N application condition, whereas transformed to “N” or inverse “V” shape after N application. In 2005, DSNC showed “N” shape under both N application and zero N application conditions. Soil Nmin content was increased by N application, especially with CU application. Nmin content was the highest in top soil layer with CU application, while higher Nmin content occurred in deeper soil layer with urea application, especially when applied 180 kg N/hm2 of urea at 9-leaf to silking stage in 2004. Coated urea showed clear slow-release effect, and simultaneously controlled the downward moving of mineral N under heavy rainfall season. Therefore, it can be speculated that coated urea can be used as a substitution of urea in maize production system in North China Plain, that help to change twice fertilization (basal and dressing) to one fertilization (basal), and thus benefit to labour-saving, profit-increasing and environment-protecting.