中文摘要：

对洞庭湖区不同土地利用方式下与主要营养元素循环相关的关键土壤酶（蔗糖酶、脲酶、碱性磷酸酶、过氧化氢酶）进行分析研究,结果表明,在0—30 cm土层,土地利用方式对4种酶活性的影响极其显著,且随土层深度的增加,土壤酶活性受土地利用方式的影响逐渐减小。碱性磷酸酶、蔗糖酶与脲酶在整个土壤剖面中受到土地利用方式的影响都较大,而过氧化氢酶对土地利用方式的响应只限于0—30 cm土层。不同土地利用方式下土壤蔗糖酶、脲酶和碱性磷酸酶活性均随土层深度的增加呈下降趋势,表明土壤有机质的分解、土壤营养元素的循环与土壤剖面结构息息相关。

英文摘要：

Activities of the four soil enzymes （i. e. invertase, urease, alkaline phosphatase and eatalase） , key to recycling of C, N and P, were studied under four different land use patterns in the Dongting Lake area. Results show that the effect of land use on soil enzyme activities in the surface layer （0-30 cm） was significant, and decreased gradually with depth of the soil profile. Among the four soil enzymes, urease, invertase and alkaline phosphatase were affected by land use throughout the entire soil profile, but the effects on catalase were only limited in the soil surface layer （0-30 cm）. All the enzymes, except catalase that did not vary much, showed a downward tendency in activity with depth of the soil profile, which suggests that soil organic matter decomposition and soil nutrient recycling are closely related to the structure of soil profile.