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通过对上海郊区的43块定位农田连续3年的跟踪监测分析,比较了50种作物以及5种不同轮作农田的氮养分平衡状况及其对土壤速效氮含量的影响。结果表明:(1)不同作物农田的氮养分盈余趋势为水生蔬菜类≥水果类>旱作蔬菜≥大田作物≥草皮;不同轮作农田氮养分盈余大小表现为:菜菜轮作>果树单作>菜作轮作>草皮单作>作物轮作;(2)不同作物及不同轮作农田收获时土壤速效氮含量随土层的加深而逐渐降低,氮养分盈余多的农田土壤的速效氮含量也高;(3)不同作物以及不同轮作农田氮养分盈余与收获时土壤表层(0~30 cm)的硝态氮和铵态氮含量呈正相关。
Through the follow-up monitoring and analysis of 43 locating farmland in Shanghai suburbs for three consecutive years, the nitrogen balance of 50 crops and 5 different cropping fields was compared and their effects on soil available nitrogen were compared. The results showed as follows: (1) The trend of nitrogen nutrient surplus in different crops was aquatic vegetables ≥ fruits> dry vegetables ≥ field crops ≥ turf. The surplus of surplus nitrogen in different crop rotation fields was: rotation of vegetables and vegetables> single fruit of vegetables> (2) The contents of available nitrogen in different crops and different rotation cropland decreased gradually with the deepening of soil depth, and the available nitrogen content in farmland soil with more nitrogen nutrient surplus was also higher (3) Nitrogen and ammonium nitrogen contents in different crops and in different rotation cropland fields were positively correlated with soil nitrate nitrogen and ammonium nitrogen content at harvest (0 ~ 30 cm).