Effects Of Straw Returning To Field And Combined Application Of Chemical Fertilizer On Soil Nutrient And Soil Enzyme Activity

Excessive use of chemical fertilizers not only destroys the quality of the soil environment and reduces soil fertility,but also causes serious resource waste and non-point source pollution problems,and the soil microbial environment is also affected.my country's crop straw output is among the highest in the world,and the pollution problem caused by the unreasonable utilization of straw resources has become one of the main factors of agricultural non-point source pollution.To this end,this study is carried out to study the effect of straw mulch returning to the field on the basic chemical properties of soil and soil enzyme activity.In this paper,six treatments were set up in the field plot test: no straw return + no fertilization(CK),optimized fertilization(O),conventional fertilization(F),straw full cover soil return + conventional fertilization(SF),straw full cover soil return Field + conventional fertilization reduction of 20%(SFR),full straw cover soil return + optimized fertilization reduction of 20%(SOR),to study the effect of straw return on soil nutrients and enzyme activity in Chaohu area.The main findings are as follows:(1)Single application of chemical fertilizer and straw returning to the field combined with chemical fertilizer can reduce the soil pH to a certain extent,while increasing soil nutrient content.Compared with F treatment,the pH value is reduced by 4.37%?11.94%,which can significantly increase the contents of organic matter and alkali-resolved nitrogen,available phosphorus,available nutrients up to 6.57%?11.81%,6.05%?11.34%,5.39%?20.40 Compared with F,SFR can reduce soil pH,total phosphorus and available phosphorus content,and significantly increase the content of alkali-decomposed nitrogen by 7.73%?11.75%.Comparing the two kinds of straw returning to the field and chemical fertilizer reduction combined application treatment,it can be concluded that SFR significantly increased organic matter and alkali nitrogen content by 7.64%?9.02%,8.83%?23.49%,respectively,compared with SOR treatment.(2)Compared with CK treatment,the activities of soil urease,phosphatase and catalase in F and O treatments were improved,but they did not reach a significant difference.Compared with F treatment,SF can significantly increase catalase activity by 7.17%?9.61%,and SFR significantly improves urease and catalase activities by 23.40%?51.61%,9.41%?16.35%,respectively.Compared with SOR treatment,SFR significantly increased catalase activity by 10.38%-26.69%.(3)There is a certain correlation between soil enzymes and soil nutrients.Soil urease has a significant positive correlation with soil available phosphorus,with a correlation coefficient of 0.674;soil phosphatase has a very significant positive correlation with soil total nitrogen and available phosphorus,with correlation coefficients of 0.703 and 0.877,respectively,with soil alkaline nitrogen and organic matter.The correlation coefficients of the significant positive correlations were 0.669 and 0.631,respectively,and there was a significant negative correlation with the soil pH,the correlation coefficient was-0.630;the soil catalase and the soil alkaline nitrogen had a very significant positive correlation,the correlation coefficient was 0.887,and There was a significant positive correlation between total soil nitrogen,total soil phosphorus and soil available phosphorus,with correlation coefficients of 0.575,0.561 and 0.582,respectively.In summary,the soil nutrient content is closely related to the change of soil enzyme activity.After the straw is returned to the field,the soil enzyme activity is enhanced,which accelerates the release rate of nutrients in the soil nutrients,thus providing a theoretical basis for the in-depth study of soil enzyme activity.