Effects Of Straw Returning And Phosphate Fertilizer On Phosphorus Uptake And Phosphorus Components In Soybean

China is a big agricultural country with abundant straw resources,producing about 600 million to 800 million tons per year.As the rural economy continues to develop,straw is no longer a major burning substance,causing excess straw to be burned in the open air,and straw burning will cause air pollution,environmental pollution,climate change,and even h uman health.Straw returning has an important impact on the sustainable production of soil,it can improve soil fertility and physical and chemical properties,save fertilizer consumption,and promote continuous crop yield increase and income increase.Soybean is native to China and is an important grain and oil combination.Its nutritional value is high.In 2019,the No.1 Document of the Central Government clearly stated: “Implementing the Soybean Revitalization Plan and expanding the planting area by multiple channels”.Soybean is a leguminous crop that needs more phosphorus.Phosphorus promotes the growth of soybean roots and is also beneficial to the formation of nodules.The phosphorus used is mainly derived from soil.Studying the effects of straw returning and applying phosphate fertilizer on soybean phosphorus uptake and soil phosphorus fraction have important production significance.In this experiment,under the rotation mode of corn-soybean planting every other year,the method of round frame planting was used to study.There are two factors of straw returning and phosphorus application amount were set,among them,straw returning to the main area,and phosphate fertilizer is applied as the secondary area.There are three ways to return the straw to the field,straw is not returned?S0?,directly returned straw?S1?,straw burned?S2?,while setting not phosphate?F0?,low phosphorus?F1?,medium phosphorus?F2?and high phosphorus?F3?four phosphorus levels.Heavy superphosphate was used for phosphate fertilizer?P₂O₅ 44%?,and the amount of heavy superphosphate treated by F0-F3 was 0,78.4,156.8,235.2 kg·hm-2.Urea?N: 46%?was used for nitrogen fertilizer,and the application rate was 87.5 kg·hm^-2.Potassium sulfate?K₂O: 30%?was used for potassium fertilizer,and the application rate was 150 kg·hm^-2.The effects of straw returning and phosphorus application on soybean dry matter quality,phosphorus content and phosphorus accumulation,soil phosphorus fraction and yield during R₁,R₅ and R₈ were studied.The results show:Straw returning and applying phosphate fertilizer have an effect on the dry matter accumulation of soybean during the three sampling periods.In addition to the irregular behavior of the R5 period,the dry matter accumulation of soybeans in the other two periods increased with the increase of phosphorus application rate;straw returning also has an effect on the dry matter accumulation of soybean,straw burning and returning to the field and straw not returning to the field is slightly higher than straw burying and returning to the field.Phosphorus accumulation in soybean increased with the phosphorus application rate,and there was irregular change in soybean phosphorus content;the effects of straw is not returned to the field,straw returning directly to the field,straw burning and returning to the field on the phosphorus content and accumulation of soybean did not show regularity;soybean yield increased with the increase of phosphorus application rate,and the yield difference betwe en straw returning treatment was not significant.Soybean phosphorus utilization rate,phosphorus fertilizer partial productivity and phosphorus fertilizer agronomic productivity all showed a downward trend with the increase of phosphorus application rate;while straw returning treatment showed irregularity.The content of different phosphorus fractions in soil was significantly affected by the level of phosphorus application,Among them,soil total phosphorus,available phosphorus,H 2O extracted phosphorus and residual phosphorus increased with the increase of phosphorus application rate;the extraction of Na OH and Na HCO3 showed irregularity with the increase of phosphorus application rate;The difference between the straw returning treatment was not obvious.