Study On The Coupling Effect Of Water And Fertilizer Of Silage Maize In Southern Xinjiang

Silage maize is used as high-quality roughage,but the management of water and fertilizer in silage maize production in southern Xinjiang is not perfect.Therefore,it is highly significant to conduct research on the water and fertilizer management system of silage maize in southern Xinjiang to solve the problem of low yield and weak economic advantage of silage maize in southern Xinjiang.In this experiment,"Xinsiyu No.12"was used as the experimental crop and four factors were established:nitrogen application rate,phosphorus application rate,potassium application rate and irrigation water volume,and secondary saturation de-optimal experimental design was used to run field experiments of silage maize water and fertilizer connections.Through the determination and analysis of growth,yield,quality and physiology,and the quadratic regression fitting of silage maize fresh grass yield,quality comprehensive score and water use efficiency,the regression model of nitrogen,phosphorus,potassium and irrigation water was established,and univariate effect,marginal effect and coupling effect analysis were carried out.The main findings are as follows:（1）With the advancement of the growth period,the plant height of silage maize in each treatment gradually increased,and in each treatment,the stem thickness,leaf area index and SPAD all showed changes of first increase and then decrease,and the maximum value appeared in the male pumping stage,and the appropriate amount of water and fertilizer could significantly improve the growth index of silage maize plants,and silage corn with nitrogen fertilizer and irrigation water at a high level could obtain better plant growth characteristics.The dry matter of the aboveground part of silage maize increased with the growth and development of plants,and the dry matter of nitrogen fertilizer and irrigation water was the highest at a higher level of T8treatment.（2）The amount of irrigation water had the greatest effect on the yield of fresh grass of silage maize,followed by nitrogen fertilizer,potassium fertilizer and phosphorus fertilizer.With the increase of the amount of N,P,K fertilizer and irrigation water,the yield of corn straw decreased obviously.The coupling treatment of nitrogen and phosphorus,water and fertilizer,nitrogen,phosphorus and potassium and water and fertilizer had obvious positive effect on the yield of fresh grass.In order to obtain a yield greater than 100 t·hm^-2silage fresh grass in southern Xinjiang,the optimal combination of nitrogen fertilizer,phosphate fertilizer,potassium fertilizer and irrigation water volume was as follows:nitrogen application rate was 281.1～302.4 kg·hm^-2,phosphorus application rate was 120.2～130.1 kg·hm^-2,application amount was 91.9～98.6 kg·hm^-2,and irrigation water volume was 3096～3261 m³·hm^-2.（3）Nitrogen fertilizer had the greatest impact on the comprehensive score of nutritional quality of silage maize,followed by potassium fertilizer,irrigation water volume and phosphate fertilizer.The comprehensive score of nutritional quality of silage maize increased first and then decreased with the input of nitrogen,phosphate,potassium and irrigation water.Through simulation and optimization,the water and fertilizer scheme with a comprehensive score of silage maize quality greater than 3 in southern Xinjiang was as follows:nitrogen fertilizer application rate was 332.0～374.9kg·hm^-2,phosphorus fertilizer application rate was 162.4～176.5 kg·hm^-2,potassium fertilizer application rate was 123.3～133.4 kg·hm^-2,and irrigation water volume was3285～3774 m³·hm^-2.（4）The water use efficiency of silage maize had the highest response to irrigation water,followed by potassium,nitrogen and phosphate fertilizers.Both fertilization and irrigation can reduce water use efficiency.Through simulation optimization,the water and fertilizer optimization scheme of silage maize water use efficiency greater than 6 kg·m^-3in southern Xinjiang was as follows:nitrogen fertilizer application rate was 241.8～264.9 kg·hm^-2,phosphate fertilizer application rate was 111.9～119.8 kg·hm^-2,potassium fertilizer application rate was 81.4～88.1kg·hm^-2,and irrigation water volume was 2 431～2 677 m³·hm^-2.（5）The nutrient accumulation of silage maize plants continues to increase with growth and development,and the appropriate amount of irrigation and fertilization of silage maize can obtain higher nutrients.Nitrogen fertilizer had the greatest effect on the nitrogen fertilizer partial productivity of silage maize,nitrogen fertilizer had a significant negative effect on the nitrogen fertilizer partial productivity of silage maize,and the other three factors were positive effects.Phosphate fertilizer had the greatest effect on the productivity of phosphorus fertilizer in silage maize,phosphate fertilizer had a significant negative effect on the productivity of phosphorus fertilizer in silage maize,and nitrogen fertilizer,potassium fertilizer,irrigation volume and other factors had positive effects on the partial productivity of phosphorus fertilizer in silage maize.Potassium fertilizer had the greatest effect on the productivity of potassium fertilizer in silage maize,followed by nitrogen fertilizer,irrigation water volume and phosphate fertilizer.Potassium fertilizer and phosphate fertilizer had significant negative effects on the partial productivity of potash fertilizer of silage maize,and nitrogen fertilizer and irrigation water had positive effects on the partial productivity of potassium fertilizer of silage maize.