Effects of Different Land Use Patterns on Soil Enzymes Activities and Chemical Properties on Riverbank Slopes of the Three Gorges Reservoir | 三峡水库岸坡系统不同用地类型对土壤酶活性和土壤化学性质的影响

Chinese. 以三峡水库岸坡系统常见的5种不同土地利用类型（林地、草地、退耕地、耕地、消落带）为对象,研究不同用地类型下土壤酶活性、土壤化学性质及其二者之间的关系。结果表明：林地土壤的过氧化氢酶、脲酶、碱性磷酸酶的活性在所有用地类型中最低,这与耕地土壤中的蔗糖酶、蛋白酶活性最低形成鲜明对照。与之相反,退耕地土壤中的脲酶、蛋白酶活性最高,而草地中的蔗糖酶、碱性磷酸酶活性居于最高。相关性分析表明：土壤过氧化氢酶、碱性磷酸酶活性与全氮、速效氮、全磷、有机质含量以及pH值分别呈现极显著的正相关,但碱性磷酸酶活性与速效磷含量呈现出极显著的负相关。蔗糖酶和脲酶活性则与全氮、速效氮、速效磷、pH值也呈显著的相关性。脲酶与有机质含量之间、蛋白酶与全氮、速效氮、pH值之间均分别呈显著相关性。林地土壤的全氮、速效氮、全磷、速效磷含量在几种用地类型中居于最低,岸坡林地能够有效减少可能进入三峡库区水体的N,P含量。消落带土壤中的速效氮、速效磷以及全磷含量在所有用地类型中最高,消落带的人为耕作可能是加剧水库水体N,P元素富营养化的重要来源之一。建议在三峡库区进一步增加林地,限制在消落带进行耕作等农事活动。

English. The soil enzyme activities and chemical properties were studied in five different land use types（i.e.woodland,grassland,abandoned land,farmland,and hydro-fluctuation belt） on riverbank slopes of the Three Gorges Reservoir.The results showed that the activity of soil catalase,urease and alkaline phosphatase in woodland was the lowest among all the land use types.In contrast,farmland had the lowest activity of the soil invertase and protease.However,abandoned land had the highest activity of the soil urease and protease,while grassland exhibited the highest activity of the soil invertase and alkaline phosphatase.Moreover,the soil catalase and alkaline phosphatase activity presented significantly positive relationship with content of soil total nitrogen,available nitrogen,total phosphorus,organic matter,and pH value,respectively.There was a significant negative correlation between alkaline phosphatase activity and soil available phosphorus content.The invertase and urease activity also showed a significant correlations with soil total nitrogen,available nitrogen,available phosphorus and pH value,respectively.In the meantime,a significant correlation was detected not only between urease activity and organic matter content,but also between protease and total nitrogen,available nitrogen,and pH values,respectively.The woodland had the lowest content of the soil total and available nitrogen,and the soil total and available phosphorus,compared to that in other land use types.The woodland might be able to effectively reduce content of nitrogen and phosphorus in the soil and hence the amont into the water body of the Three Gorges Reservoir.However,the content of soil available nitrogen,available phosphorus and total phosphorus in the hydro-fluctuation belt was the highest compared to that in other land use types The continuous agricultural farming in the hydro-fluctuation belt could be one of the crucial sources for inputting nitrogen and phosphorus into the water body of the reservoir to cause eutrophication.Thus,woodland should be further increased while imposing farming should be restricted in the hydro-fluctuation belt of the Three Gorges Reservoir area.This study provides useful knowledge for protecting results can be of help to protect riverbank slopes of the Three Gorges Reservoir.