Effect Of Biochar Application On Soil Structure And Organic Carbon Fraction In Dry Framland

Biochar is a highly aromatic substance which made by pyrolysis of plant biomass under the 0xygen or completely anaerobic environment.Due to its special properties,it can improve soil construction,increase soil carbon content.This study set up a experiment that input different quality of biochar(0t/hm~2,10t/hm~2,20t/ hm~2,30t/hm~2,40t/hm~2,50t/hm~2)in dry farmland and rearch the soil structure,soil water holding capacity,soil organic carbon and its components.The order is explore the mechanism of the biochar addition to the soil structural characteristics and organic carbon components in dry farmland.This study aim to provide scientific basis and theoretical support for the development of soil moisture management and soil improvement measures.The critical conclusions are following:1)In dry farmland,the biochar addition can improve the soil structure,reduce the soil bulk density,increase soil capillary pore content,but it has little effect on soil non-capillary pore.With the increase of biochar input level,the change of soil bulk density and porosity are increased.2)The stability of mechanism-stable aggregates and water-stable aggregates decreased in initial stage of biomass application.But as time go on the stability will increase slowly.3)The Gardner model has good effect on the soil water holding curve in dry farmland which input the biochar,and the correlation coefficient is above 0.90.From the fitting results,it can be found that soil water holding capacity and water supply capacity increased with the increase of biomass carbon input level.When the biochar input level reached 40 t/hm~2,the soil water holding capacity and water supply capacity is stable.And the effect of biochar on soil water holding capacity decreases with the increase of water suction.4)The biochar addition can increase soil saturated water content,field water holding capacity and soil effective water content.After the biochar input level reached 40 t / hm~2,the soil water content was saturated,the field water holding capacity and the soil available water content were the best and stabilized.Biochar can increase the wilting coefficient,but the effect is not obvious.In conclusion,the addition of biochar in dryland can improve the soil water constant,and the soil water holding capacity is the best when the input level is 40 t /hm~2.5)The biochar application can significantly increase the soil TOC,ROC,MBC,HFOC content,But the impact of biochar on HWOC is little.And the effect of biochar application on carbon pool index was significant,which could significantly increase soil organic carbon content,active organic carbon content,soil carbon pool index(CPI)and soil carbon management index(CPMI).