棕壤长期定位试验结果表明,覆膜使表层土壤中NH4+-N含量明显增加,并使各个层次NO3--N含量都有所增加,有效地减少了NO3--N的淋失。研究同时表明施用有机肥和化肥都能提高土壤全氮、碱解氮、NH4+-N、NO3--N含量,而施用单一的氮肥则对土壤碱解氮几乎没有影响。因此,有机肥与无机肥配合施用是培肥覆膜土壤氮素肥力的有效措施。 The results of long - term brown locating experiment showed that the content of NH4 + -N in topsoil increased obviously and the content of NO3 - N in all layers increased, which effectively reduced the leaching of NO3 - N. The results also showed that both organic and chemical fertilizers could increase soil total N, available N, NH4 + -N and NO3 - N contents, whereas application of a single N fertilizer had little effect on soil available N. Therefore, the combination of organic fertilizer and inorganic fertilizer is an effective measure to fertilize the nitrogen fertility of soil covered by plastic film.