不同沙化程度高寒草原土壤酶活性及微生物数量特征

Characteristics of Soil Enzyme Activities and Microorganism Quantity in Alpine Grasslands With Different Degrees of Desertification

以轻度沙化、中度沙化、重度沙化、极度沙化4个沙化程度的高寒草原土壤为研究对象,采用室内测定配方法,分别采集深度为0~10、10~20、20~30 cm的土壤样品,测定不同沙化程度各土层中土壤蔗糖酶、脲酶、过氧化氢酶、蛋白酶活性及土壤细菌、放线菌、真菌数量,并做相关性分析,探究不同沙化程度高寒草原土壤酶活性及微生物数量特征,分析沙化对土壤酶活性及微生物数量的影响,旨在为草原生态系统的稳定发展提供参考依据。结果表明:1)随着沙化程度的加剧,蔗糖酶活性、蛋白酶活性呈减小趋势,脲酶活性呈先增大后减小趋势,过氧化氢酶活性呈先减小后增大趋势。2)细菌、放线菌、真菌数量均随沙化的加剧呈减小趋势。3)同一沙化程度不同土层下,酶活性及微生物数量随土层深度的增加逐渐减小。4)脲酶、过氧化氢酶、蛋白酶与细菌、放线菌间有一定相关性,与真菌无明显相关性。由此可见,高寒草原严重沙化会导致土壤酶活性有所降低,微生物数量急剧下降,土壤质量状况下降。

The mild desertification,moderate desertification,severe desertification,and extreme desertification of alpine grassland soil were selected as the research objects.The soil samples,which were collected from 0-10,10-20 cm,and 20-30 cm,respectively,were used to test the soil sucrase activity,urease activity,catalase activity,protease activity and the number of soil bacteria,actinomycetes,and fungi in these soil samples under different degrees of desertification,and did correlation analysis.In order to explore the characteristics of soil enzyme activity and microbial quantity in the alpine grassland with different degrees of desertification,based on these test results,it was analyzed that the soil enzyme activity and microbial quantity affected by desertification.The results showed that,1)as the degree of desertification intensifies,the activities of soil sucrase and protease decreased gradually,the activity of urease increased first and then decreased,and the activity of catalase first decreased and then increased.2)The number of bacteria,actinomycetes,and fungi showed a decreasing trend with the increasing of desertification.3)Under the same degree of desertification,soil enzyme activity and microbial quantity decreased gradually with the increasing of the soil depth.4)Urease activity,catalase activity,and protease activity had a certain correlation with bacteria and actinomycetes,but there was no obvious correlation with fungi.It could be seen that the severe desertification of the alpine grassland lead to a decrease in soil enzyme activity and a sharp decline in the number of microorganisms,soil quality decline.