Effect of N,P,K and S Fertilization on Photosynthetic Characteristics and Grain Yield of Winter Wheat

The experiments were carried out on the farm of Henan agricultural university,during 2003~2004,using high-gluten cultivar Yumai 34 as material.This study was to clarify photosynthetic characteristics and grain yield variations with different N,P,K and S rates,so as to provide some experimental foundations for reasonable N,P,K and S fertilization of wheat.The results of the study revealed that under the field fertility of this experiment,rates of N,P,K and S had obvious adjust effect on canopy photosynthetic rate,chlorophyll content and nitrate reductase activity,and all photosynthetic characteristics indices increased with N,P,K and S supply,but the most powerful fertilizer factor at different date after anthesis was different.Combined fertilization of N,P,K and S also obviously regulated grain yield,and effect of S and N on yield was at 0.01 significant level,while effect of P and K was not.N70P120K180S30 treatment was the optimum combination.