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大白菜是京郊蔬菜生产的主要菜种,近年来种植面积虽然有所减少,但它在城乡居民蔬菜消费中仍占有不可忽视的地位。在大白菜的化肥施用中,偏施氮肥现象较为严重。相当流行的一种看法认为大白菜是叶菜类作物,应该多施氮肥。这是一种误解。大白菜产量高,需要氮素较多,但是,它对钾钙磷的需要量也是不小的。从京郊土壤养分中氮磷钾的供应情况来看,玉米等大田作物的三要素需要程度是氮大于磷和钾;而对大白菜来说、则是氮磷钾三者同等缺乏,施用磷钾肥和施用氮肥一样重要。
Chinese cabbage is the main vegetable species produced in the suburbs of Beijing. Although its planting area has decreased in recent years, it still occupies a place of neglect in urban and rural residents’ vegetable consumption. In Chinese cabbage fertilizer application, partial nitrogen fertilizer is more serious. A very popular view that cabbage is a leafy crop should be more nitrogen fertilizer. This is a misunderstanding. High yield of Chinese cabbage needs more nitrogen, however, its demand for potassium, calcium and phosphorus is not small. In view of the supply of nitrogen, phosphorus and potassium in the soil nutrients in the suburbs of Beijing, the demand of the three elements of field crops such as corn is greater than that of phosphorus and potassium. For Chinese cabbage, the three factors of nitrogen, phosphorus and potassium deficiency are the same. Potash is as important as applying nitrogen fertilizer.