Effects of spatial coupling of watering and fertilization on winter wheat photosynthetic characteristics and grain yield
水肥空间组合对冬小麦光合特性及产量的影响

A soil column experiment was conducted with a fertile Eum-Orthic Anthrosols to study the effects of spatial coupling of watering and nitrogen(N)-and phosphorus(P)fertilization on the photosynthetic characteristics and grain yield of winter wheat.The column consisted of three layers,each layer being 30 cm in thickness and with an underlying 2 cm layer of coarse sand to obstruct water-and nutrient exchange.The results showed that relative content of chlorophyll(SPAD),net photosynthetic rate(Pn),and grain yield were significantly lower in the treatment of 0-30 cm soil drought and 30-90 cm soil wetness(D)than in that of 0-90 cm soil wetness(W).In these two watering treatments,a combined application of N and P got the highest SPAD,Pn and grain yield,followed by applying P,and N.The SPAD,Pn and grain yield were significantly higher when the fertilizer N was applied in 0-90 cm layer than in 0-30,30-60 and 60-90 cm layers,respectively.No significant differences in SPAD,Pn and grain yield were observed when fertilizer P was applied in 0-90 cm layer and in 0-30 cm layer.In treatment W,the SPAD,Pn and grain yield were the highest when N and P were applied in 0-90 cm layer,had no significant differences with those when the N and P were applied in 0-30 cm layer,but were significantly higher than those when the fertilization was carried out in 30-60 and 60-90 cm layers.In treatment D,no significant difference in SPAD was observed when the N and P were applied in different layers,but Pn and grain yield were significant higher when the N and P were applied in 0-90 cm than in 30-60 cm layer,and in 30-60 cm than in 60-90 cm layer.It was concluded that whether in treatment W or in treatment D,a combined application of N and P should be carried out in 0-30 cm soil layer.