蔬菜施用氮肥有讲究在蔬菜生产特别是叶菜类的生产中，施用氮肥应注意以下几点：１早施。蔬菜早施氮肥有利于促幼苗早发快长和早熟，而且可使氮素有较充分的时间转化为人体有益的营养物质，减少蔬菜中硝酸盐的积累。一般蔬菜在苗期追施氮肥最好；不易积累硝酸盐的蔬菜，... Vegetable nitrogen fertilizer stress There are particular emphasis on the production of vegetables in the production of leafy vegetables, the application of nitrogen fertilizer should note the following: 1 early application. Early application of nitrogen fertilizer is conducive to promoting early seedlings grow faster and precocious, but also allows more time for nitrogen to be transformed into beneficial nutrients for the human body to reduce the accumulation of nitrate in vegetables. General topdressing nitrogen in seedling best; difficult to accumulate nitrate vegetables, ...