【摘要】 通过在陕西杨凌进行的3年田间试验研究了减氮+秸秆还田以及添加双氰胺（DCD）对旱地雨养区冬小麦-夏休闲种植模式小麦产量和氮平衡的影响.试验共设置不施氮肥（CK）、施氮220 kg·hm^-2+秸秆不还田（FP）、施氮150 kg·hm^-2+秸秆还田（OPT）和施氮150kg·hm^-2+秸秆还田+7.5 kg·hm^-2双氰胺（OPT+DCD）4个处理.结果表明:与FP相比,OPT处理产量略降低,但差异不显著,而氮肥利用率增加6.1%,氮肥表观损失率减小7.2%;OPT+DCD处理小麦产量和氮肥利用率均最高,且氮肥表观损失率最低,3年平均产量分别比OPT和FP高10.4%和7.9%,氮肥利用率高20.8%和28.1%,氮肥表观损失率减少8.5%和15.1%.施肥40⁴5 d内,添加DCD可以提高表层土壤NH₄⁺-N的含量,减少NO₃^--N的累积.更多还原

【Abstract】 In a 3-year field experiment,effects of reducing N fertilizer,straw returning and dicyandiamide（ DCD） application on wheat yield and nitrogen budgets under wheat-fallow system were studied in rain-fed region. The experiment was carried out in Yangling of Shaanxi Province,and 4 treatments were installed including no nitrogen（ CK）,220 kg N · hm^-2 and no straw returning（ FP）,150 kg N·hm^-2 and straw returning（ OPT）,150 kg N·hm^-2,7.5 kg·hm^-2 DCD and straw returning（ OPT + DCD）. The results showed there was no remarkable difference for wheat yield between OPT and FP,but the N use efficiency of the former was 6.1% more than that of the latter,and the apparent N loss ratio was 7.2% less. OPT+DCD increased the average yield of winter wheat by 10.4% and 7. 9% respectively compared to OPT and FP,the N use efficiency of winter wheat increased by 20. 8% and 28. 1%,and the apparent N loss ratio decreased by 8. 5% and 15.1%,respectively. NH₄⁺-N content in 0- 20 cm of soil increased,accordingly the NO₃^--N content decreased in 40 to 45 days when DCD was applied.更多还原