青海高原长期复种绿肥毛叶苕子对土壤供氮能力的影响

利用绿肥的培肥效应,小麦收获后复种绿肥毛叶苕子。在复种绿肥毛叶苕子的情况下,研究后茬作物油菜生育期土壤全氮、碱解氮、硝态氮、铵态氮的时空变化。结果表明,油菜生育期0～100 cm土层全氮、碱解氮、铵态氮积累量均表现为有毛叶苕子处理高于无毛叶苕子处理,硝态氮积累量均表现为有毛叶苕子处理低于无毛叶苕子处理。毛叶苕子与化肥配施效果好,毛叶苕子施用对提高和保持土壤全氮、碱解氮、铵态氮含量,相比CK提高9.54%～18.33%,相比纯施化肥提高0. 94%～19. 28%。化肥配施毛叶苕子处理较单施化肥土壤硝态氮含量降低7.01%～38.51%。绿肥引入小麦(油菜)种植体系后,对小麦(油菜)生长季内土壤氮库、氮素循环及培肥土壤产生一定影响。

Effects of long-term green manurehairy vetch on soil nitrogen supply on the Qinghai Plateau

In this experiment, we studied the effect of green manure crop, hairy vetch, on spatial and temporal variation of soil N in the rapeseed field. hairy vetch was planted after wheat was harvested followed by planting rapeseed. The results showed that the total N, available N, NO^-₃-N, and NH⁺₄-N in the soil during the growth period of the rapeseed (Brassica napus L.) were higher than those in plots untreated with hairy velvet, however, the vetch treatment resulted in lower NO^-₃-N in the soil than that in untreated soil. The results also showed that the combination of hairy vetch green manure and chemical fertilizers had better results than CK and chemical fertilizers did along. The green manure improved the total N, available N, NO^-₃-N, and NH⁺₄-N from 9.54% to 18.33% than CK and 0.94% to 19.28% over chemical fertilizers. It also resulted in lower NO^-₃-N content in the soil in a range of 7.01% to 38.51% than chemical fertilizers. Therefore, the application of green manure in the wheat-rapeseed cropping system improves soil nitrogen, nitrogen cycling, and soil fertility during the growing season of wheat-rapeseed.