Effect Of Corn Stover Incorporation With Different Ways On Composition And Structural Characteristics Of Soil Humus

At present,most of the research is about the effects of different types of straw,different dosage and different fields on soil physicochemical properties and structure,but the study of time based measurements is rare.So this experiment based on time,control the amount of straw returning to the field(full amount),five treatments were set as follows:CK(No corn stover incorporated),CS2(corn stover incorporated to shallow layer),CS3(corn stover deep incorporation),CS4(corn stover and shallow layer soil evently mixed to surface soil),CS5(corn stover and deep layer soil evently mixed to deep soil).The changes of soil physical and chemical properties,available nutrients,humus composition and structure characteristics of black soil under different returning methods and depths of corn stover were studied in the field experiment,and provide a theoretical basis for soil organic fertilize and carbon fixation.Results showed:(1)There was no significant change in soil pH and electrical conductivity after returning corn stover in different ways.With the increase of corn stover returning time,the differences in soil pH and conductivity were also not significant.The content of N,P and K in soil was improved,and there was significant difference.The corn stover shallow and deep incorporation have a more significant effect on the nutrient content of surface and subsurface soils.The mixture of corn stover and soil is more beneficial to the increase of soil available nutrients.The content of N in soils showed an irregular trend with the increase of corn stover returning time,and both the available P and K showed an increasing trend.(2)After returning corn stover in different ways,the soil bulk density decreased,and the subsurface layer decreased more than the surface;The soil moisture content increases,corn stover deep incorporation effect is better;Soil tightness increases with depth.The corn stover shallow and deep incorporation have a more significant effect on the tightness content of surface and subsurface soils.With the increase of corn stover returning time,the soil bulk density showed an upward trend,and the water content was the opposite.(3)After adding the corn stover,the content of organic matter in soil was improved.The organic matter in soil of surface layer was increased more by corn stover shallow application.The corn stover deep also makes subsurface organic carbon in soil change more obvious.The mixture of corn stover and soil is more beneficial to the increase of organic carbon in soil.After returning corn stover in different ways can increased the composition of organic carbon,PQ value and ΔlogK of HA.With the increase of corn stover returning time,the organic carbon content and logK value of HA increased,PQ value increased significantly.(4)After adding the corn stover,the condensation degree and thermal stability of the HA structure decreased,the content of aliphatic chain hydrocarbons increased,and the aromatic carbon content reduced.The effect of corn stover shallow application and deep treatment on 0 ~ 20 cm and 20 ~ 40 cm soil layer was more obvious.With the times going on,the condensation degree and aroma of HA structure increased,and the content of aliphatic chain hydrocarbons decreased.