Effects of straw and straw-derived biochar with equal carbon incorporation on soil stability and conversion of carbon
[Objective]The paper aimed to investigate the effects on carbon stability and carbon conversion of soil incorporated by straw and straw-derived biochar under different water conditions.[Method]The soil culture experiments were conducted to explore the concentration of soil organic carbon(SOC),dissolved organic carbon(DOC),microbial biomass carbon(MBC),easily oxidized organic carbon(ROC),and the emission of CO2 and CH4,in which the soil was incorporated with equal amounts and straw or straw-derived biochar,respectively,and in-cubated at 60％,100％,and alternating wet and dry conditions of the maximum water holding capacity of the soil field.[Result](ⅰ)After 60 days of incubation,equal carbon addition of straw and biochar increased soil organic carbon by 48.02％-53.91％and 31.55％-42.39％,respectively,and soil microbial carbon increased by 243.20％-258.16％and 85.67％-101.09％,respectively,and the organic carbon loss rate was shown as straw treatment(29.27％-34.95％)＞biochar treatment(12.25％-21.79％),and the cumulative emissions of CO2 and CH4 in straw treatment were 75.40％-398.43％and 1394.61％-3201.17％higher than those in biochar treatment,respective-ly,indicating that although straw could significantly increase the total organic carbon of the soil,at the same time,it stimulated the loss of or-ganic carbon of the soil,and increased the emissions of CO2 and CH4,and the carbon sequestration and emission reduction effect were smaller than that of biochar treatment.(ⅱ)Soil water content significantly affected the soil organic carbon loss rate and carbon emission.The SOC loss rates of different exogenous carbon addition treatments all showed 60％of maximum water holding capacity(12.25％-29.29％)dry-wet alternation(16.61％-29.27％)＜100％of maximum water holding capacity(21.79％-34.95％).The cumulative CH4 emis-sions of straw treatment at 100％of maximum water holding capacity and the wet-dry alternation treatment were 200.96％and 139.35％higher than those at 60％water holding capacity,respectively,which were greater than those of CK.However,the effect of moisture on cumu-lative CH4 emission from biochar treatment was small,increasing by 36.26％and 20.31％,respectively,which was smaller than that of CK.This was due to the higher content of ROC of straw,and the promotion of CH4 emission resulting from 100％filed water holding capacity.[Conclusion]Compared with straw,biochar returning to field can improve SOC content and reduce the rate of soil carbon loss.At the same time,biochar can mitigate the influence of the difference in oxygen environment caused by soil water content on soil carbon patterns,and ef-fectively reduce CO2 and CH4 emissions per unit mass of soil.
BiocharWater contentStability of soil carbonConversion of soil carbonCarbon emission
万方数据
维普
