Effects Of Different Phosphorus Rates In Wheat Season On Yield And Nitrogen And Phosphorus Utilization In Wheat-Maize Rotation System

Winter wheat-summer maize rotation is an important planting system in the Guanzhong region of Shaanxi,China.However,there is currently little research on the effects of phosphorus application during the wheat season on the productivity and fertilizer efficiency of the rotation system.Exploring the impact of a single application of phosphorus in the wheat season on the production of the wheat jade rotation system in the Guanzhong region of Shaanxi Province,and clarifying the optimal amount of phosphorus application for the wheat season based on yield and soil nutrient optimization,can provide scientific basis for optimizing soil phosphorus management,improving crop yield in the rotation system,and increasing cost saving and efficiency of phosphorus fertilizer in green production.This study focuses on the winter wheat-summer maize rotation system in the Guanzhong region,and sets up field positioning experiments with different phosphorus application rates(0,75,150,225,and 300 kg P₂O₅·hm^-2)during the wheat season.Through two years of research,the wheat and maize yield,nutrient accumulation and transportation,soil available phosphorus content,and soil nitrogen form transformation characteristics under different phosphorus application rates during the wheat season were analyzed.Suitable phosphorus fertilizer input thresholds were proposed from the perspectives of yield and environmental safety,and the relationship between nitrogen and phosphorus nutrients and yield was explored.The main research results obtained are as follows:1.Phosphorus application during the wheat season significantly affects the yield and dry matter accumulation of wheat-maize rotation.The yield and dry matter accumulation of wheat-maize were higher under phosphorus application of 150 and 225kg P2O5·hm^-2.Regression analysis showed that the yield and dry matter accumulation of wheat,maize,and wheat-maize rotation in the second year of the experiment showed a parabolic trend of first increasing and then decreasing with the increase of phosphorus application.The yield of wheat,maize and wheat-maize rotation reached its highest at191,204,and 195 P2O5·hm^-2,respectively,the corresponding phosphorus application rates for achieving the highest dry matter accumulation are 226,202,and 219 kg P₂O₅·hm^-2.2.The application of phosphorus during the wheat season significantly affects the absorption and utilization of phosphorus nutrients in wheat-maize rotation crops.The accumulation of phosphorus in wheat and maize is higher at 150 kg P₂O₅·hm^-2and 225kg P₂O₅ hm^-2of phosphorus application.The accumulation of phosphorus in crops shows a parabolic trend of first increasing and then decreasing with the increase of phosphorus application.With the increase of phosphorus application,the utilization efficiency and agronomic efficiency of wheat-maize phosphorus fertilizer show a decreasing trend,while the soil available phosphorus content shows an increasing trend.3.Different phosphorus application during the wheat season significantly affected the transformation of soil nitrogen forms and crop nitrogen uptake and utilization in wheat-maize rotation.The nitrogen accumulation in wheat and maize was higher at 150and 225 kg P2O5·hm^-2 of phosphorus application.The accumulation of nitrogen in crops shows a parabolic trend of first increasing and then decreasing with the increase of phosphorus application.Applying phosphorus during the wheat season can regulate the changes in nitrogen forms and source sink relationships in the rhizosphere soil of wheat and maize,improve nitrogen and phosphorus availability,and promote crop yield formation.Wheat yield,phosphorus accumulation,and available phosphorus content showed a significant positive correlation with IEN and CN,while maize yield,phosphorus accumulation,and available phosphorus content showed a significant positive correlation with CN.4.In summary,a single application of phosphorus during the wheat season can meet the nutrient requirements of the wheat-maize rotation system in the Guanzhong region,achieving high yield in the rotation system and cost saving and efficiency enhancement of phosphorus fertilizer.Taking into account economic and environmental benefits,it is recommended to use 95%of the highest wheat yield as the target yield for wheat season phosphorus fertilizer application under the experimental conditions.This can save 41%of phosphorus fertilizer usage while achieving higher crop yield,dry matter production,and nitrogen and phosphorus nutrient utilization efficiency in crop rotation.As an optimized soil phosphorus management measure,it is beneficial for the high and stable yield,fertilizer conservation,and efficiency increase of the wheat-maize rotation system in the region.