放牧对青藏高原东缘高寒草甸土壤酶活性及土壤养分的影响

对青藏高原四种不同放牧强度(围栏封育、轻牧、中牧和重牧)高寒草甸的土壤酶活性、土壤养分和植被群落特征进行了研究,探讨了不同放牧强度土壤酶活性和土壤养分及植被群落的相关性.结果表明:各样地土壤酶活性、士壤养分和植被群落特征有较大差异.土壤纤维素酶和淀粉酶活性与土壤有机质、速效氮质量分数及地上生物量变化一致,表现为围栏封育>轻牧>中牧>重牧,然而脲酶活性的变化趋势正好与之相反,表现为随着放牧强度的增加而增加.酸性磷酸酶活性和地下生物量变化一致,表现为轻牧>围栏封育>中牧>重牧.经分析,土壤酶活性和土壤养分密切相关,其中土壤淀粉酶和脲酶活性与土壤养分和植被特征的相关性最好,因此这两种酶活性可以作为评价青藏高原高寒草甸土壤质量的指标之一.

Impact of grazing on the activities of soil enzymes and soil nutrient factors in an alpine meadow on the Qinghai-Tibetan plateau

A comparative study on the soil enzyme activities,soil nutrients and plant community properties with different grazing intensities(zero grazing,light grazing,moderate grazing and heavy grazing) was conducted in an alpine meadow on the Qinghai-Tibetan plateau(in Maqu county,Gansu) and the relationships between soil enzyme activity,soil nutrient and plant community properties were discussed.The results indicated that soil enzyme activities,soil nutrients and plant community properties differed obviously among different grazing intensities.The activities of cellulose and amylase were in the order of zero grazing>light grazing>moderate grazing>heavy grazing,and the content of soil organic matter,available nitrogen and above-ground biomass were in the same order.However,the changing trend of urease activities was just opposite to them.The activities of acid phosphatase and underground biomass were in the order of light grazing>zero grazing>moderate grazing>heavy grazing.Pearson correlative analysis showed that the activities of amylase and urease were significantly related to soil nutrients and plant community properties.Therefore,the activities of amylase and urease were viable means for predicting the soil quality.