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通过对川南坡地进行退耕试验,研究坡地退耕成慈竹林、杂交竹林、桤木+慈竹林和弃耕地对土壤腐殖质及团聚体碳和氮的影响。结果表明,坡地退耕5年后土壤腐殖质(胡敏酸、富里酸和胡敏素)、活性腐殖质(活性胡敏酸和活性富里酸)及团聚体碳和氮含量、胡敏酸与富里酸比值和胡敏酸E4/E6值,以及可浸提腐殖质(胡敏酸和富里酸)、活性腐殖质及>0.25mm各粒径团聚体碳和氮分配比例均增加,并呈现出慈竹林>杂交竹林>桤木+慈竹林>弃耕地>农耕地的变化规律。土壤团聚体有机碳(氮)含量及其分配比例随土壤团聚体粒径的增加呈现出“V”形变化,其最小值分别出现在2～1mm和0.5～0.25mm粒径。说明川南坡地退耕对增加土壤腐殖质及团聚体碳和氮含量、改善土壤肥力状况和促进土壤碳固定具有重要的作用和意义。
This paper studied the effects of returning cultivated land to Cixi bamboo forest, hybrid bamboo forest, Alnus creased wood and Ci bamboo forest and abandoned farmland on soil humus and aggregate carbon and nitrogen in the south slope of Sichuan Province. The results showed that the content of humus (humic acid, fulvic acid and humin), active humus (active humic acid and active fulvic acid) and aggregates carbon and nitrogen, humic acid and fulvic acid ratio and Hu The values of E4 / E6 and the proportion of humus (humic acid and fulvic acid), active humus and carbon and nitrogen fractions of aggregates> 0.25 mm in diameter all increased, and the relationships of Ci bamboo forest> hybrid bamboo forest> 桤Wood + Cizhu Lin> Abandoned Farmland> Change of Agricultural Lands. The content of organic carbon (N) and its distribution proportion in soil aggregates showed “V” shape change with the increase of soil aggregates’ particle size, and the minimum value appeared in 2 ~ 1mm and 0.5 ~ 0.25mm particle size respectively. It is concluded that returning cultivated land on slopes in the south of Sichuan Province plays an important role in increasing soil humus and aggregates carbon and nitrogen content, improving soil fertility and promoting soil carbon fixation.