将玉米上、下位叶片裁成微区,分析各区的含钾量,证实玉米叶片各微区含钾分布的不均衡性,愈近茎秆的微区含钾量愈高;收获期各微区含钾量均低于吐丝期;凡对穗形成贡献大的叶片含钾量下降幅度就大.追施钾肥对果穗上部叶片含钾量增加就显著.玉米生育期叶片营养诊断,可判断玉米钾素营养丰缺,但采取矫治措施,为时已晚.苗期全株诊断效果优于生育后期.比较之下,测定土壤速效钾以指导钾肥施用要优于植株营养诊断. The upper and lower leaves of corn were cut into micro-regions, and the content of potassium in each region was analyzed to confirm the uneven distribution of potassium in each micro-region of corn leaves. The more the content of potassium in the micro-regions of the stalk was higher, Potassium content is lower than the silking stage; where the contribution to the formation of large leaves of the leaves of potassium decreased significantly. Topdressing potassium on the upper leaves of the upper leaves of potassium increased significantly. Corn growth during vegetative diagnosis, can determine the corn Potassium nutrition abundance and deficiency, but to take corrective measures, it is too late.The whole plant seedling diagnosis is better than the late growth stage.Compared with the determination of soil available potassium to guide the application of potassium fertilizer is better than the plant nutrition diagnosis.