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一、缺氮1.症状表现玉米苗期缺氮,植株生长缓慢、矮瘦、叶色黄绿、抽雄迟;生长盛期缺氮,老叶从叶尖沿着中脉向叶片基部枯黄,枯黄部分呈V字型,叶缘仍保持绿色而略卷曲,最后呈焦灼状而死亡。2.防治措施中等肥力玉米田,667米2施尿素24~30千克,分3次施用。第1次在苗期,施用量占氮肥总量的20%;第2次在大喇叭口期,施用量占氮肥总量的70%;第3次在抽雄开花期,施用量占氮肥总量的10%。二、缺磷1.症状表现根系发育差,苗期生长缓慢,5叶期后明显出现缺磷症状,叶片呈紫红色,叶缘卷曲,并且缺磷还会使花丝抽出速度慢,造成雄、雌花不育,影响授粉,并且果穗卷缩,穗行不齐,籽粒不饱满,常出现秃顶现象,成熟期延迟。
First, the lack of nitrogen 1. Symptoms of corn seedling nitrogen deficiency, plant growth is slow, thin, yellow and green leaves, tasseled late; growth of nitrogen deficiency, the old leaves along the midrib from the tip to the base of the leaves yellow, yellow part Was V-shaped, leaf margin remains green and slightly curly, finally scorched like death. 2. Control measures Medium fertility corn fields, 667 m 2 urea 24 to 30 kg, divided into 3 applications. The first time in the seedling stage, the application amount accounted for 20% of the total amount of nitrogen fertilizer; the second time in the big bell mouth period, the application amount accounted for 70% of the total amount of nitrogen fertilizer; the third time in the tasseling flowering stage, Of the 10%. Second, lack of phosphorus 1. Symptoms of poor root development, seedling growth is slow, 5-leaf stage after the apparent symptoms of phosphorus deficiency, leaves were purple, leaf margin curly, and lack of phosphorus will also make filaments extracted slowly, resulting in male, Female sterile, affecting pollination, and ear curling, uneven rows, the grain is not full, often appear bald phenomenon, the maturity of the delay.