京郊蔬菜种植面积逐年扩大,复种指数不断提高,随着有机肥料施用量的急剧減少,氮肥施用量的增大,同时又忽视磷、钾肥的配合使用,就引起了氮、磷、钾肥比例的严重失调。近年来,蔬菜作物尤其是瓜、果、豆类单产严重下降,品质变次,病害严重。国内外大量研究 The area under vegetable cultivation in the suburbs of Beijing increased year by year and the index of multiple cropping increased continuously. With the drastic reduction in the amount of organic fertilizers and the increase of the amount of nitrogen fertilizers, ignoring the combination of phosphorus and potassium fertilizers, the proportion of nitrogen, phosphorus and potassium fertilizers Serious disorders. In recent years, the yield of vegetable crops, especially melon, fruit and bean, has dropped seriously, the quality has changed and the disease has become serious. A large number of domestic and foreign research