读者来信:蔬菜施肥如何控氮?答:无公害栽培蔬菜要禁用硝态氮肥和以硝态氮肥为原料生产的复合肥。采用科学施肥方法:基肥以腐熟的有机肥为主,配合施用磷钾肥。追肥要根据蔬菜不同生育阶段肥料的需要量大小分次追肥。注意基肥要分层施、深施或沟施。叶面喷施或结合浇水追肥。大力推广有机肥,减少氮肥用量。要多用充分腐熟的优质畜禽粪 Reader letter: How to control nitrogen fertilization of vegetables? A: The pollution-free cultivation of vegetables to ban the use of nitrate nitrogen and nitrate fertilizer as raw material for the production of fertilizer. The use of scientific methods of fertilization: basal fertilizer to decomposed organic fertilizer-based, with the application of phosphorus and potassium fertilizer. Top-dressing according to the needs of different stages of fertilization of vegetables, the size of the top-grade fertilizer. Note that base fertilizer should be layered facilities, deep facilities or ditch facilities. Foliar spray or combined with top dressing. Vigorously promote organic fertilizer, reduce the amount of nitrogen fertilizer. To use more fully cooked high-quality livestock and poultry manure