追氮和垄膜沟播种植对晋南旱地冬小麦氮素利用的影响

在自然降水条件下,通过2年大田试验研究了追氮、垄膜沟播种植对晋南旱地冬小麦生育期地上部氮素吸收累积,02 m土层氮素残留、损失及氮肥利用率和氮素平衡的影响。结果表明: 追氮和垄膜沟播种植均可显著提高旱地冬小麦地上部氮素累积量和氮肥利用率,苗期和返青至抽穗期是冬小麦氮素吸收累积的两个高峰期,分别占到最大累积量的20%46%和29%57%。追施氮的利用率高于基施氮的利用率; 随施氮量增加,土壤残留无机氮（Nmin）增加,主要集中在060 cm土层,2040 cm土层为硝态氮积累的峰值区,垄膜沟播种植可以减少土壤残留无机氮（Nmin）,但增加了氮的表观损失量; 冬小麦生长季土壤氮输出以表观损失为主,氮肥表观损失率在4087%7629%之间,且主要发生在播前至返青期。本试验条件下,综合氮素吸收累积、土壤残留、氮肥利用率及氮素平衡等因素,旱地冬小麦应采取氮肥后移顶凌追施和垄膜沟播相配套的种植方式。

Effects of topdressing nitrogen and plastic film mulched ridge-sowing furrow cultivation on nitrogen utilization of winter wheat on rainfed lands in Southern Shanxi

Nitrogen application amount and time directly affect its uptake,accumulation and translocation in winter wheat,and furthermore affect the yield formation.Too much nitrogen fertilizer would result in low nitrogen use efficiency,high production costs and environmental pollution.Water deficit is the major restriction factor for improving nitrogen utilization efficiency in rainfed lands.Therefore,it is of great importance to apply N fertilizer and match cultivation measure rationally for increasing winter wheat...