玉米秸秆还田方式对土壤胡敏酸含量及组分的影响OA

To explore the effects of different tillage measures on soil humic acid content and structural characteristics under straw returning,the farmland soil with long-term(8 years)straw returning was taken as the research object,and no straw returning(CK),straw mulching(NTS),straw burial(BTS)and straw rotary tillage(MTS)treatments were set up.The fluorescence spectral characteristics of soil humic acid under different straw returning methods were studied by combining three-dimensional fluorescence spectroscopy and parallel factor analysis.The results showed that different straw returning methods were all beneficial to the accumulation of humic acid content in topsoil(0-10 and 10-20 cm).NTS treatment significantly increased the content of humic acid in 0-10 cm soil layer(35.25％),while BTS treatment had the best accumulation of humic acid content in 10-20 cm soil layer(9.80％).The three-dimensional fluorescence spectrum analysis showed that soil humic acid was affected by the interaction of autochthonous and exogenous sources,showing strong humification characteristics.Four fluorescent components C1,C3,C4(humic acid substances)and C2(fulvic acid substances)were identified by parallel factor analysis.The three straw returning treatments showed that the soil humification degree of straw enrichment layer was higher.To sum up,different straw returning methods significantly affected the content of soil humic acid in each soil layer,which in turn affected the structure and composition of soil humic acid in different soil layers.The results of this study provided a theoretical basis for studying the effects of straw returning methods on the properties of humic acid in semi-arid black soil area.