Effect Of Water Deficit And Fertilization On Growth And Water And Nutrient Use Of Maize And Soybean

Study on the effect of moderate water deficit on growth and water- and nutrient- use has scientific significance in crop production.This paper dealt with the effect of water deficit on maize(Zea Mays L.)and soybean(Giycine max L.Merrill)growth,dry mass accumulation or yield,water- and nutrientuse under different fertilization level.Seven water deficit treatments in different growth stages of maize were designed for experiment 1 and 2.Two fertilization levels(F₁ and F₂)for experiment 1 and three N fertilization levels (N₁,N₂ and N₃)were designed for experiment 2,respectively.Seven water deficit treatments in different growth stages of soybean and three K levels(K₁, K₂ and K₃)were designed for experiment 3.The main results are outlined as follows:1.Slight water deficit in the seedling- early jointing(A₃)and later jointing - heading(B₂)stages did not reduce total dry mass of maize significantly.Under F₁ and F₂ condition,A₃B₂ increased water use efficiency of maize(WUE_maize)compared to conventional irrigation treatment.And under different N treatments,different water deficit treatments in different stages generally increased WUE_maize.And the WUE_maizewas increased with the application of N fertilizer in certain range of N level.2.Compare to the conventional irrigation treatment,the medium water deficit in seedling - branching stage and slight water deficit in podding -maturity stage increased seed yield of soybean by 24.47%,24.25%and 39.37%,and water use efficiency on seed(WUE_seed)by 47.06%,55.00%and 60.71%in K₁,K₂ and K₃ treatments,respectively.Thus the medium water deficit in seedling - branching stage and slight water deficit in podding -maturity stage can effectively improve the yield and WUE_seed.Furthermore, the yield and WUE_seedof soybean were enhanced with the application of K fertilizer.3.Compare to the control treatment,slight water deficit treatment in the early seedling-jointing and later jointing - heading stage of maize increased plant N,P and K contents,but reduced soil available N,P and K contents.At K₂ level,medium water deficit in seedling - branching stage and slight water deficit in podding - maturity stage of soybean increased plant N,P and K contents effectively,and reduced the soil available N,P and K contents when compared to the control treatment.4.Leaf MDA content in different water deficit treatments of soybean was higher than that of CK,but it was decreased with the increased K fertilizer. Thus the water stress in plant can be relieved by supplying certain amount of K fertilizer.Furthermore,leaf chlorphyll content of soyban was increased by applying appropriate K fertilizer.The above-mentioned results indicated that slight water deficit in both seedling- early jointing and later jointing - heading stages of maize increased N,P and K contents,but did not reduce total dry mass significantly.The medium water deficit in seedling - branching stage and slight water deficit in podding - maturity stage of soybean can effectively improve the yield, WUE_seedand plant N,P and K contents.Furthermore,N application increased the WUE_maizeof maize in certain range of N rate and K application enhanced the yield and WUE_seedof soybean.