三江源不同海拔高寒草原表层土壤酶活性特征

Characteristics of enzyme activity in surface soilof alpine steppe under different altitudes on Qinghai-Tibetan Plateau

摘要:

为了解三江源地区高寒草原土壤酶活性随海拔变化的规律及其影响因素,在三江源地区选取5个不同海拔高寒草原,并对其地上植被特征,4种土壤酶活性和9种土壤理化性质进行了分析测定。结果表明:海拔变化对高寒草原地上植被生物量影响不大,而海拔升高引起草地盖度和多样性升高及草层高度的降低。随着海拔梯度的上升土壤磷酸酶活性呈上升趋势,土壤多酚氧化酶,过氧化物酶和脱氢酶则随海拔梯度的上升先增加后降低,土壤容重,含水量和pH呈降低趋势,全氮和有机质含量呈上升趋势,而全磷和全钾则无显著变化。冗余分析表明,对土壤酶活性具有显著影响的土壤因子是pH、总碳和土壤含水量,而植被因素为禾本科草生物量。

Abstract:

The characteristics of enzyme activity in surface soil of alpine steppe under different altitudes (3094,3227,3470,3901 and 4200 m) in Sanjiangyuan region on Qinghai-Tibetan Plateau were studied in order to explore the variation patterns of activity of soil enzymes (phosphatase,polyphenol oxidase,peroxidase,dehydrogenase).The results showed that the altitude had little effect on the vegetation biomass of alpine steppe,but the increased elevation increased the plant coverage and diversity of steppe,while decreased the grass height.Soil phosphatase activity increased with altitude,while soil polyphenol oxidase,peroxidase and dehydrogenase increased first and then decreased with the increase of altitude gradient.And with the altitude,the soil bulk density,water content and pH decreased,the total nitrogen and organic matter content showed reversed trends,while total phosphorus and potassium showed no significant change.Redundancy analysis showed that pH,organic carbon and moisture contents and the proportion of gramineae in vegetation were the main factors affecting significant effects on soil enzyme activities.