中文摘要：

【目的】研究干热河谷地带不同土地利用方式对土壤酶活性的影响。【方法】以四川宁南县金沙江下游的河谷地带为研究区域,选择相同海拔下的7种主要的土地利用方式为研究对象,于2008年通过室内测试分析,并运用统计和相关分析等方法,研究干、湿季下的土壤酶活性变异特征。【结果】干热河谷地带土地利用方式对土壤酶活性影响显著,脲酶、蔗糖酶、磷酸酶、纤维素酶总体变化规律相似,水桐树林土壤酶活性显著高于其它土地利用方式,其次是草地和合欢林,花椒地、玉米地、甘蔗地和桑地酶活性最低;过氧化氢酶活性整体变幅不大,玉米地、桑地、甘蔗地活性低于其它土地利用方式;多酚氧化酶活性和其它酶活性变化规律不同,其中桑地和合欢林最高。除多酚氧化酶外,总体上相同土地利用方式下湿季酶活性要显著高于干季。相关性分析表明土壤蔗糖酶、脲酶、磷酸酶、过氧化氢酶不仅相互之间关系密切,而且与主要土壤肥力因子相关性显著,可以作为评价土壤肥力的指标。土壤酶指数（SEI）可以客观、全面地反映土壤酶活性特征,7种土地利用方式SEI从大到小依次为水桐树林、合欢林、天然草地、玉米地、花椒地、甘蔗地和桑地,其中湿季的SEI要明显高于干季。【结论】不同土地利用方式由于特殊的耕作环境、物种构成等因素导致了土壤酶活性的差异性,为了实现干热河谷地带生态系统的健康发展,从土壤酶学角度应在该区域尽量选择人为干扰较少,物种丰富的土地利用方式。

英文摘要：

【Objective】 The study of soil enzyme activity on land use is of importance for exploration of the soil quality evolution and its evaluation during the revegetation in Jinsha river dry-hot valley region.【Method】 Seven kinds of land use types with the same altitude at valleys in downstream of Jinsha river in Ningnan county,Sichuan was chosen as subject,aiming at reveal the changes in soil enzyme activity under wet/dry alternate conditions through experimental and statistical analysis.【Result】 The results showed that different land use types significantly influenced the enzyme activity.Soil urease,saccharase,phosphatase,cellulose behaved the same change.Compared to other land use,a higher enzyme was found in Camptotheca acuminata,followed by grassland and Albizzia julibrissin,the lowest in Zanthoxylum bungeanum,Zea mays,Saccharum sinense and Morus alba.No significant change was observed in catalase activity and the lower value was found in Zea mays,Morus alba,Saccharum sinense than other land use.Different changes were observed in polyphenol oxidase from other enzymes,and the Morus alba and Albizzia julibrissin corresponded the highest value.With a exception of polyphenol oxdiase,enzymes with the same land use at wet season were higher than that in dry season.Correlation analysis showed a significant relation among saccharase,urease,phosphatase,and catalase,also related with soil fertility indicators,therefore soil enzyme could be useful for reflecting soil fertility.Soil enzyme index（SEI）can objectively and fully evaluate the change in soil enzyme,the SEI changed with an order of Camptotheca acuminata Albizzia julibrissin grassland Zea mays Zanthoxylum bungeanum Saccharum sinense Morus alba,and the SEI in wet season was higher than dry season.【Conclusion】 The significant difference was observed in different land use types owing to special factors such as framing environment and species composition.In order to realize the healthy development in dry-hot valley,the soil enzyme change should be take