Effect Of Tillage Method And Straw Return On Improvement Of Lime Concretion Black Soil And Maize Yield Increase

The method of soil tillage and straw returning to the field was adopted in this experiment,which is of great significance for improving the surface quality and improving yield of the soil.On the basis of 6-year fixed tillage experiment,4-year fixed tillage treatments will be set from 2018 to 2019,namely autumn rotary tillage +straw returning(RT + NS,control),autumn rotary tillage + straw returning(RT + AS),autumn subsoiling + straw returning(SS + AS),autumn deep ploughing + straw returning(DMP + AS),In this paper,the effects of tillage layer regulation and straw returning on soil characteristics,soil nutrients,soil respiration rate,microbial bacterial diversity,crop growth and yield,irrigation efficiency and economic benefits were studied,The results provide the main basis for the research and development of the control measures to alleviate the soil compaction and improve the yield and efficiency of corn.The main findings are as follows1.Soil physical properties can be improved by soil plough layer regulation.Soil compaction and R value of soil three-phase ratio can be significantly reduced during maize silking stage.In order to improve soil plough layer quality,it is necessary to increase soil moisture.On the basis of straw returning,soil compaction in SS+ AS and DMP + AS decreased by 7.0% and 17.2%,soil three-ratio R value in SS + AS and DMP + AS decreased by 1.2% and 5.1%,and soil water content increased by 5.9%and 6.8%,respectively.Compared with RT+NS treatment,straw returning reduced soil compactness by 6.4% and soil three ratio R by 5.7%,and increased soil water content by 1.8%.Therefore,the effect of straw returning is greater than that of soil regulation.In DMP + AS treatment,soil compaction decreased by 24.9%,soil three phase ratio R decreased by 10.3%,and soil water content increased by 3.3%.2.Soil topsoil treatment can increase soil nutrients,and affect soil organic matter,alkali hydrolyzable nitrogen,available phosphorus and available potassium to some extent.In the 10-60 cm soil layer,DMP+ AS and SS+ AS treatments increased soil organic matter,available nitrogen,available phosphorus and available potassium by12.0%,20.7%,52.9%,14.4% and 11.2%,11.3%,29.5%,10.8%,respectively,compared with RT+NS treatments.Among the four treatments,DMP + AS treatment had the best improvement effect on soil organic matter,alkali hydrolyzable nitrogen,available phosphorus and available potassium,and its content in soil was also the highest.3.Topsoil treatment can increase the respiration rate in soil.The soil respiration rate increased by 30.4% due to the regulation of topsoil.The effect of straw returning increased by 13.0%.Compared with RT + NS treatment,SS + AS treatment and DMP+AS treatment increased soil respiration rate by 35.9% and 58.9%,respectively.On the basis of straw returning,SS + AS treatment and DMP + AS treatment increased soil respiration rate by 20.2% and 40.7%,respectively,which was significantly different from RT + NS treatment.4.Soil surface treatment can improve soil surface structure,improve soil porosity,pore volume,pore area and soil microorganism diversity,and reduce the number of soil pores.Deep tillage combined with straw returning could increase soil porosity,pore volume and pore area by 12.7%,39.7% and 31.5% respectively,and reduce the number of pores by 33.7%.The regulation of soil plough layer mainly increases beneficial microorganisms in soil,increases the unique bacterial population,enriches the diversity of soil bacteria,has good control effect on the ecological environment of soil microorganism,and provides favorable growth environment for crop growth and development.5.Soil topsoil regulation can improve soil irrigation efficiency.There was significant difference between DMP + AS treatment and RT + NS treatment,and the irrigation use efficiency of DMP + AS treatment was the highest.Compared with RT +NS treatment,irrigation use efficiency of SS +AS treatment and DMP +AS treatment increased by 11.9% and 8.2% respectively.Deep ploughing could increase the irrigation efficiency by 7.0%,while straw returning could increase the irrigation efficiency by 2.9%.6.The regulation of soil layer increased the accumulation of dry matter and nutrient.Compared with RT+NS treatment,SS+AS treatment increased dry matter accumulation,nitrogen accumulation,phosphorus accumulation and potassium accumulation by 10.3%,26.8%,20.1% and 27.0%,respectively;DMP + AS treatment increased dry matter accumulation,nitrogen accumulation,phosphorus accumulation and potassium accumulation by 10.6%,24.8%,22.2% and 31.7%,respectively.The accumulation of nitrogen,phosphorus and dry matter increased by 15.8%,2.5% and16.8% respectively.Straw returning increased dry matter accumulation by 6.3%,nitrogen,phosphorus and potassium accumulation by 8.2%,5.3% and 10.1%,respectively.Therefore,the effect of soil layer regulation on plant dry matter accumulation was greater than that of straw returning,and the effect of straw returning on plant nitrogen,phosphorus and potassium accumulation was greater than that of soil layer regulation.7.The regulation of soil plough layer could promote the growth and function of crop root system,increase the root length,root volume,root dry weight,root activity and active absorption area,but had no significant effect on the diameter of crop root system among treatments.Compared with RT + NS treatment,SS +AS increased root length,root volume and root dry weight by 29.4%,33.1% and 24.2%,respectively,The root length,root volume and root dry weight of DMP + AS increased by 40.9%,37.2% and 30.0%,respectively.The root activity and active absorption area of SS + AS and DMP + AS increased by 10.3%,5.5% and 17.4%,9.3%,respectively.The promotion of DMP + AS on root growth and function was greater than that of SS + AS,and was significantly different from that of RT + AS.8.Soil topsoil regulation can increase crop yield and economic benefits.Compared with RT +NS treatment,DMP +AS treatment increased grain number per ear,effective panicle number,1000 grain weight,yield and economic benefit by 8.5%,8.4%,3.7%,11.7% and 16.9%,respectively,SS + AS increased grain number per ear,effective ear number,1000 grain weight,yield and economic benefit by 6.6%,11.8%,9.5%,3.7% and 10.8%,respectively.Soil tillage increased crop yield and economic benefit by 6.2% and 6.6% respectively,while straw returning increased crop yield and economic benefit by 2.9% and 6.9% respectively.The results showed that the regulating effect of soil plough layer was greater than that of straw returning.