A Held experiment in Iijiabu, Dingxi City of Gansu province, was carried out based on improving nitro gen use efficiency and reducing the pollution of nitrogen fertilizer. Four treatments, namely flat-planting with no mulching (NM), half-mulching and flat-planting(HM) , complete-mulching and flat-planting(CM), completely mulched alternat ing narrow and wide ridges with furrow planting(CMRF), were designed to study accumulation of residual NO3- - N and dynamic accumulation and distribution of dry matter and nitrogen use efficiency. The results showed that in the whole growth period of mulching treatments NO3 - N content of 0 ~ 10 cm soil layer was highest and were significantly higher than that of NM, indicating there existed NO3 - N surface accumulation in mulching treatments. NO3 - N content of ' all treatments under 140 cm soil layer was accumulated. The average nitrogen accumulation in the whole growth period was: CMRF > CM > HM > NM. Compared with CM and NM, grain nitrogen accumulation of CMRF was increased by 20.48% and 87.87% , showing that CMRF significantly enhanced plants nitrogen utilization from soil, as well as transport of nitrogen to grain Biomass yield of CMRF was 37.60 % higher than that of HM, maize yield was increased by 49.84% , and nitrogen harvest index was significantly increased by 22.55% compared with HM. During different treatments nitrogen use efficiency of maize was significantly different at 0.05 level, CMRF was significantly increased by 53.98% than NM.%以提高玉米氮素利用效率、减少氮肥污染为目标,在甘肃省定西市李家堡设置了露地(NM)、半膜平作(HM)、全膜平作(CM)和全膜双垄(CMRF)沟播等田间试验处理,对其土壤剖面中NO3- -N的积累强度、玉米干物质积累及氮素利用效率进行了系统研究.结果表明:整个生育期覆膜处理在0～ 10 cm表层中NO3- -N浓度最高,明显高于NM,具有表聚现象.所有处理NO3- -N含量在140 cm土层以下均有积累.全生育期植株平均氮素积累量表现为:CMRF＞ CM＞ HM＞ NM.籽粒氮积累量CMRF较CM和NM高出20.48％和87.87％,说明CMRF显著增强了植株对土壤氮的利用和氮素向籽粒的转运.生物产量CMRF较HM增产37.60％,经济产量增产49.84％,氮素收获指数CMRF较HM显著提高22.55％.不同处理之间的NUE差异显著(P＜0.05),CMRF较HM显著提高53.98％.
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