The Effect Of Combined Application Of Nitrogen And Phosphorus On Yield And Physiology On The Winter Wheat & Summer Maize In The Drought Region

By researching the effect of combined application of Nitrogen and Phosphorus on the drought-resistance in dry farming crops under the winter wheat/summer maize rotation system on sloping farmland in west of Henan through field experiment,we have mainly drown following conclusions:1.Combined application of N and P fertilizers could increase the output,the ratio of output to input and the fertilizer efficiency of rain-fed winter wheat/summer maize on the slope farmland in western Henan.2.The treatment of N₁₂₀P₉₀ in wheat season and the treatment of N₂₄₀P₁₈₀ in maize season are the best treatments for improving the accumulation and metastasis rate of N and P elements,the nutrient recovery rate decreased with the increase of fertilizer.3. Suitable combined of N and P fertilizers significantly increased the drought-resistance of winter wheat/summer maize,which could improve output of the winter wheat/summer maize.4.Suitable combined of N and P fertilizers significantly increased the content of chlorophyll and leaf relative water content(RWC) of winter wheat flag leaf and summer maize function leaf,the roles of nitrogen is better than that of phosphorus,meanwhile, only when the nutrient was balanced,would certain water be maintained and Chlorophyll be formed in leaves,and both had a very significant difference with the treatment of N₂₄₀P₁₈₀.5.The treatment of N₁₂₀P₉₀ is the best in decreasing MDA content and increasing the antioxidant enzyme(SOD,POD,CAT) activity of winter wheat flag leaf,its maloaldehyde(MDA) content was 62.7%compared with that of the control treatment of N₀P₀,the activity of SOD,POD,CAT were increased by 39.40%,52.40%,80.36%, respectively,comparing to the control treatment(N₀P₀).The treatment of N₂₄₀P₁₈₀ is best for summer maize,its maloaldehyde(MDA) content at filling stage was 32.05% compared with that of the control treatment of N₀P₀,which at anthesis stage was 44.48% compared with that of the control treatment of N₀P₀.The activity of SOD,POD,CAT at filling stage were increased by 55.03%,1.16times and 1.71 times,respectively,comparing to the control treatment(N₀P₀),which at anthesis stage were increased by 89.96%,1.71times and 1.52times.In this experiment,applying nitrogen and phosphorus fertilizers was beneficial to improving Fv/Fo values(PSâ…¡activity),Fv/Fm values(potential photochemical efficiency of PSâ…¡),ΦPSâ…¡values(practical quantum yield of PSâ…¡) and qP(photochemical quenching component),while the contents of NPQ(nonphotochemical quenching component) decreased,and compared with the processings which stops applying fertilizer,The Fv/F0,Fv/Fm,φpsii and qP of the maize which continues to apply fertilizer are also higher,but the NPQ of the processings which stops applying is higher than the processing which continues to apply fertilizer.But employee excessive phosphorus fertilizer cannot exhibit a obvious advantage.When nitrogen application reached to 240kg/hm²,the Fv/Fo values of each winter wheat treatments manifested as P₉₀＞P₁₈₀＞P₀;The Fv/Fm values of each winter wheat treatments manifested as P₉₀＞P₁₈₀＞P₀ without nitrogen fertilizer application.With the complication of nitrogen and phosphorus fertilizers,Fv/F₀,Fv/Fm,φPSâ…¡and qP values of the N₂₄₀P₁₈₀ treatment were much higher than that of other treatments,while the NPQ was significantly lower than that of other treatments.Among them,while compared N₂₄₀P₁₈₀ with N₀P₀,NPQ of winter wheat decreased by 17.36%.It was further suggested that combined ample application of N and P fertilizers could significantly improve the activate photosynthesis of summer maize,and photosynthetic efficiency was obviously improved.