NITROGEN NUTRITIONAL DIAGNOSIS AND RECOMMENDATION AS TOPDRESSING FERTILIZER N FOR SEVERAL CROPS IN NORTH CHINA Ⅱ. DIAGNOSIS NITRATE IN PLANT TISSUE BY QUICK TEST METHOD

Two quick test methods(diphenylamine method and nitfate test .strip) for test nitrate N in plant tissue and the relationship for two method used in spring wheat, winter wheat and corn were Studied in field and laboratory. The results suggested that both of two methods could be used as nitrogen quick test methods in practice. The test value measured by the nitrate test strip was more accaracy than that of diphenylamine method, and had a good relationship with that of continue flow analysisa(CFA)and chromatography method. So the nitrate test strip could be used as a common test method with the quick and simple character. The diphenylamine method could indicate the nitrogen status in plant which changed with the different rate of nitrogen fertilizer application. it is more suitable to be used in the practice. The results also indicated that the test vlaue measured by two methods had a similar relationship:different crops.