| The technology of returning agricultural waste Biomass to the field is an Effective means to improve the ecological environment of farmland and promote the sustainable development of agriculture.The return of Biomass to the field will definitely improve the physical and chemical properties of the soil and improve the soil fertility,but how the blending of different Biomass in the soil affects the infiltration characteristics of the fertilizer solution and the distribution of water and fertilizer under irrigation and fertilization conditions is not clear.In order to prove the effect of returning biomass to soil on the distribution characteristics of soil water and fertilizer in the integrated water and fertilizer mode,a red soil was used as a test soil sample to carry out an indoor one-dimensional vertical infiltration test.Assume 3 kinds of biomass,namely（bio-chars BC;coffee grounds CG;sugarcane bagasse SB）and 5 addition ratios(no addition A0:0 g·kg-1;low addition ratio AL:5 g·kg-1;medium addition ratio AM:10 g·kg-1;medium-high addition ratio AM-H:15 g·kg-1;high addition ratio AH:20 g·kg-1).The effect of adding biomass under irrigation and fertilization mode on soil infiltration characteristics and water and fertilizer distribution was studied.The conclusions reached are as follows:（1）The cumulative infiltration amount and the distance of wet front migration increase with the infiltration time,and the infiltration rate decreases with the infiltration time.Compared with A0 treatment,the cumulative infiltration amount,wet front and infiltration rate are inversely proportional to the amount of biomass applied.The cumulative infiltration amount of the soil under different biomass treatments is expressed as:A0>BC>CG>SB;the order of the migration distance of the wet front is expressed as:A0>SB>BC>CG.（2）Soil water content,available nutrient content and electrical conductivity are positively correlated with the amount of biomass applied.The water content,available phosphorus content,and available potassium content of all treated soils decreased with the increase of soil depth,while the nitrate nitrogen content and electrical conductivity increased with the increase of soil depth.The water content of the tested soil under different biomass treatments is roughly expressed as:CG>BC>SB>A0;the nitrate nitrogen,available phosphorus and available potassium content of the tested soil under different biomass treatments are all expressed in sequence:CG>BC>SB>A0.The electrical conductivity of the tested soil under different biomass treatments is expressed as:CG≈BC>SB>A0（3）When there is no leaching,the infiltration rate and infiltration time conform to the Kostiakov and Philip infiltration models;the wetting front and infiltration time satisfy the power function model,and the coefficient a decreases with the increase of the biomass addition ratio,and the index b increases with The increase in the amount of biomass added increases.In the Philip simulation results,the absorption rate S and the stable infiltration rate A decrease with the increase of the biomass input,while in the Kostiakov simulation results,the coefficient B decreases with the increase of the biomass input.（4）Compared with the treatment without A0,the leaching rate and cumulative leaching amount are negatively correlated with the amount of biomass applied;the leaching rate decreases with the increase of time.The cumulative leaching amount under different treatments is expressed as:A0>CG>BC>SB.（5）When leaching occurs,compared with the A0 treatment,the soil moisture content,available nutrients and electrical conductivity increase with the increase of the amount of biomass applied,namely:A0<AL<AM<AM-H<AH.The water content of the soil under different biomass treatments is roughly expressed as:CG>BC≈SB>A0;the available nutrient content of the tested soil under different biomass treatments is expressed as:CG>BC≈SB>A0;the size of the electrical conductivity The degree is roughly expressed as:CG>BC>SB>A0.（6）Compared with A0 treatment,the concentration and conductivity of available nutrients in the leaching solution decreased with the increase of biomass addition.The relationship between the content of available nutrients and the conductivity of the leaching solution under different biomass treatments is shown as follows:SB>BC>CG.To sum up,CG treatment is the best in terms of water and fertilizer retention and reducing soil nutrient leaching... |
