Effects of potassium fertilizer application time on chlorophyll fluorescence parameters of the flag leaf and on yield of winter wheat in northern Henan sandy soil

With the treatment of no potassium fertilizer application as CK,120 kg·hm-2 potassium fertilizer(K2O) total basal dressing and 120 kg·hm-2 potassium fertilizer(K2O) 1/2 basal dressing+1/2 top dressing were used to study the effect of potassium fertilization application time on winter wheat yield and relitive phsiological parameters in northern Henan sandy land.The results showed that the treatment of potassium fertilizer 1/2 basal dressing +1/2 top dressing was better than that of potassium fertilizer total basal dressing at increasing Fv/Fm,PS Ⅱ and qP and reducing NPQ,the former was also better at increasing soluble protein content and chlorophyll SPAD value,improving the SOD activity and reducing MDA levels in leaf than the latter.Thenefore the treatment of potassium fertilizer 1/2 basal dressing +1/2 top dressing was better at increasing the grains per spike,the 1 000-grain weight and the yield.