以吴县黄泥土为供试土壤,在盆钵条件下设置不同轮作处理,观测粮食作物、绿肥、牧草对土壤C、N的影响。结果表明,N素平衡主要靠施肥,C素平衡主要靠施用有机肥。不施有机肥的粮田有机质均有耗损;若把两季根茬计入,水田可达平衡;二年中有一季绿肥的旱地,C素仍不能平衡。稻麦轮作收入N素大,但必须投入比粮食作物更多N。豆科牧草可获得大量的生物N,但必须用大量磷钾肥去换。 Taking Wuxian yellow soil as test soil, different rotation treatments were set up under the conditions of pots and pots to observe the effects of food crops, green manure and pasture on soil C and N. The results show that, N balance depends mainly on fertilization, C balance mainly by the application of organic fertilizer. Organic matter without organic fertilizer grain fields are depleted; if the two seasons of stubble included, paddy fields up to balance; two years in a dry season of green manure, C elements are still not balanced. Rice and wheat crop income N large, but must invest more than food crops. Legume forage can get a lot of biological N, but must be replaced with a large number of phosphorus and potassium.