缺氮 绝大部分蔬菜缺氮或氮肥不足时,整个植株生长衰弱,茎细、叶子小。底部老叶先开始变黄,逐渐向上部叶片发展,全株变成淡黄色或褐色,最后叶枯死脱落。补救办法:(1)每亩追施尿素7～8公斤或用人粪尿600～700公斤对水浇施。(2)叶面喷肥,每亩用1％ Nitrogen deficiency Most vegetables lack of nitrogen or nitrogen deficiency, the entire plant growth and weakness, thin stems, leaves small. At the bottom of the old leaves began to turn yellow, and gradually to the upper leaves of the development, the whole plant into a light yellow or brown, and finally the leaves died. Remedy: (1) top dressing of urea per acre 7 to 8 kg or 600 to 700 kg of human waste water facilities. (2) foliar fertilizer, with 1% per mu