覆盖和粮草间作对作物氮素吸收利用和土壤硝态氮累积的影响

为了减少普通地膜和氮肥的投入,实现该地区农业生态良性循环和土壤的可持续利用,在甘肃武威试验站采用完全随机裂区设计,研究了不同种植模式（玉米单作、玉米//毛苕子和玉米//箭筈豌豆）和覆盖方式（普通地膜覆盖、生物可降解地膜覆盖、秸秆覆盖和无覆盖）对玉米和绿肥作物氮素吸收以及土壤硝态氮累积的影响。结果表明：覆盖和间作对作物的氮素吸收利用具有显著促进作用。玉米收获期,与无覆盖相比,普通地膜覆盖、生物可降解地膜覆盖和秸秆覆盖的玉米植株吸氮量分别增加21.46%,11.22%和34.63%,与玉米单作相比,玉米//毛苕子和玉米//箭筈豌豆的玉米吸氮量分别增加6.94%和6.26%。玉米收获期,秸秆覆盖的牧草植株吸氮量较普通地膜覆盖、生物可降解地膜覆盖和无覆盖分别增加46.75%,72.31%和21.76%,间作毛苕子的吸氮量较间作箭筈豌豆增加25.26%。玉米收获期,各处理玉米带、牧草（裸露）带0～140cm土壤硝态氮累积量均低于牧草收获期,无论牧草收获期还是玉米收获期,单作玉米的玉米带、裸露带土壤硝态氮累积量均低于间作玉米。玉米收获期,普通地膜覆盖和生物可降解地膜覆盖的玉米带0~140cm土壤硝态氮累积量较无覆盖分别显著增加32.87%和27.82%,普通地膜覆盖的牧草（裸露）带0～140cm土壤硝态氮累积量较生物可降解地膜覆盖、秸秆覆盖和无覆盖分别增加9.17%、6.07%和35.45%。

Effects of mulching methods and intercropping on crops nitrogen uptake and soil NO-3-N accumulation

In order to maintain the sustainable development of agriculture and to reduce the inputs of nitrogen fertilizer and common plastic film in agricultural production, a experitment with completely randomized split-plot design was conducted from March to October in 2013 at Gansu Agricultural University Experiment Station, Huangyang Town, Wuwei C maize//hairy vetch intercropping and plastic mulching, biodegradable fi ty, Gansu Province. Effects of planting patterns （maize monoculture, maize//common vetch intercropping） and mulching methods （common m mulching, straw mulching and no-mulching） on crop nitrogen uptake and nitrate nitrogen （NO3^- -N） accumulation in soil were studied in the experiment. The results showed that mulching and intercropping promoted the nitrogen uptake by crops. At maize harvesting stage, compared with no-mulching, the increases of nitrogen uptake by maize under common plastic film mulching, biodegradable film mulching and straw mulching were 21.46 %, 11.22 % and 34.63 %, respectively. Compared with maize monocul- ture, the increases of nitrogen uptake by maize with maize//hairy vetch intercropping and maize//common vetch intercropping were 6.94% and 6.26 %, respectively. At maize harvesting stage, compared with common plastic film mulching, biodegradable film mulching and no-mulching, the increases of nitrogen uptake by forages under straw mulching, were 46.75% ,72.31% and 91.76% ,respectively,Compared with intercropping common vetch, the nitrogen uptake of intercropping hairy vetch significantly increased by 25.26%. At maize harvesting stage, the soil NO3^- -N accumulation from 0 to 140 cm in the maize belts and forage belts were below than that at forages harvesting stage. Whether at forages or maize harvesting stage, soil NO3^- -N accumulation in the maize belts and forage belts of maize monoculture were below than that in intercropping maize. At maize harvesting stage, compared with no-mulching, the increases of soil NO3^- -N accumulation in the maize belts under common plastic