不同pH玉米田土壤团聚体稳定性及有机碳含量变化OA

To investigate the changes in soil aggregate composition,stability,and organic carbon content in acidified corn fields,soils with different pH values were selected through soil investigation in the same planting mode of corn fields for experiments.Five treatments were set with soil pH val-ues,T1(4.95),T2(5.41),T3(5.82),T4(6.07)and T5(6.09),to determine composition and stability of soil aggregates,distribution of organic carbon and aggregate organic carbon,calculate contribution rate of aggregate organic carbon,analyze the relationship between aggregate stability and soil organic carbon distribution,and explore the interaction between soil aggregate stability and organic carbon in acidified corn fields.In the mechanically stable aggregates of acidified corn field soils,the content of>2 mm sized aggregates was relatively high.In the water-stable aggregates,the content of aggre-gates with a particle size of 1-0.5 mm was relatively high,R0.25(content of aggregates with a particle size>0.25 mm)decreased with the increase of soil pH value.The organic carbon content of soil ag-gregates in acidified corn fields with particle sizes of 1-0.5 mm and 0.5-0.25 mm was relatively high,both organic carbon content of bulk soil and organic carbon content of aggregates with different particle sizes were correlated with soil C/N,among which the correlation coefficient with bulk soil or-ganic carbon was the highest(0.905).There was a significantly negative correlation between soil pH value and bulk organic carbon and organic carbon content of each particle size of aggregates.The cor-relation between soil pH value and organic carbon content of 0.5-0.25 mm particle size was the high-est,with a correlation coefficient of-0.972.The results indicate that soil acidification can promote the accumulation of organic carbon by increasing the contribution rate and C/N of large aggregate or-ganic carbon.