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选取-5~5℃作为研究温度,以24 h(12 h冻结,12 h消融)为一个冻融循环,研究吉林西部大安灌区水田0~30 cm土壤有机碳以及土壤酶活性(脱氢酶、多酚氧化酶、过氧化氢酶和脲酶)的剖面特征,分析了二者之间的相关性。结果表明:冻融过程中,土壤有机碳、脱氢酶、多酚氧化酶、过氧化氢酶和脲酶均随土壤深度的增加而递减;0~10 cm土壤有机碳含量增加,10~20 cm和20~30 cm土壤有机碳含量降低,其变化趋势与含水率一致;过氧化氢酶变化较小,脱氢酶和脲酶总体增加,而多酚氧化酶活性降低;土壤有机碳与酶活性的相关性大小表现为:脲酶>多酚氧化酶>脱氢酶>过氧化氢酶。冻融作用改变了土壤中水环境,抑制了土壤微生物呼吸和酶的分解作用,影响土壤有机碳的积累。
A series of freeze-thaw cycles of 24 h (12 h freeze and 12 h ablation) were chosen to study the relationship between soil organic carbon and soil enzyme activities (dehydrogenase, Polyphenol oxidase, catalase and urease) profile characteristics, the correlation between the two was analyzed. The results showed that soil organic carbon, dehydrogenase, polyphenol oxidase, catalase and urease all decreased with the increase of soil depth in the process of freezing and thawing. The content of organic carbon in 0-10 cm soil layer increased, And the soil organic carbon content decreased from 20 to 30 cm. The change trend was in line with the water cut; the change of catalase was small, the dehydrogenase and urease generally increased, but the activity of polyphenol oxidase decreased; the content of soil organic carbon and enzyme activity Correlation size showed: urease> polyphenol oxidase> dehydrogenase> catalase. Freezing and thawing has changed the water environment in the soil, inhibited the respiration of soil microorganisms and enzyme decomposition, affecting soil organic carbon accumulation.