Effect of Years of Straw Returning on Soil Aggregates and Organic Carbon in Rice-wheat Rotation Systems
In order to reveal the change characteristics and the response mechanisms of the soil aggregate stability and organic carbon fractions to different years of straw returning in rice-wheat rotation systems,a field experiment was conducted to determine the effects of years of straw returning on the soil aggregate distribution characteristics and soil aggregate stability indexes (Mean Weight Diameter MWD,Geometric Mean Diameter GMD and Fractal Dimension D),and to study their relationships with soil organic carbon fractions.The results of the study showed that under the condition of straw returning,soil macroaggregate content R0.25,MWD and GMD increased significantly,and the fractal dimension D decreased significantly,and the trend was more obvious with the increase of years of straw returning,but the improvement effect on MWD and fractal dimension D under short-term straw returning (within 5 years) was not significant.The long-term straw returning significantly increased soil total organic carbon TOC,but there was no significant difference in TOC between the treatments of short-term straw returning (within 5 years) and no straw returning.Both long-term and short-term straw returning could enhance the active organic carbon AC significantly.The multiple regression analysis showed that compared to AC,soil aggregate structure stability could promote the growth of TOC.GWD had the most significant correlation with soil organic carbon fractions,and it was more suitable for revealing the relationship between soil aggregates and organic carbon fractions.
years of straw returningsoil aggregatessoil organic carbonrice-wheat rotation
国家科技期刊平台
NSTL
万方数据
维普
