植被恢复模式对川西北沙化草地土壤微生物量及酶活性研究

Effect of Vegetation Restoration Pattern on the Soil Microbial Biomass and Enzyme Activity in Desertification Grassland of Northwest Sichuan

为研究不同植被恢复模式对高寒沙化草地治理过程中土壤微生物量及酶活性的影响,以川西北高寒沙化草地为研究区,以未恢复沙化草地为对照(CK),通过野外试验与室内分析相结合的方法对围栏禁牧布设沙障恢复模式(WLCD)、围栏禁牧布设沙障撒播草种(RGCD)和围栏禁牧布设沙障混播燕麦草种(YMCD)3种植被恢复模式下沙化草地的土壤微生物量以及土壤酶活性的变化规律和相互关系的研究。结果表明:(1)3种植被恢复模式下土壤微生物量碳氮、多酚氧化酶、蔗糖酶、脲酶与硝酸还原酶活性均显著高于CK(P<0.05),其中YMCD变化最显著。与CK相比,YMCD土壤微生物量碳氮、多酚氧化酶、蔗糖酶、脲酶与硝酸还原酶活性均增加了217.52%,725.26%,130.88%,387.78%,300.33%,192.32%;(2)随着土层的加深,微生物量碳氮、脲酶、蔗糖酶、多酚氧化酶与硝酸还原酶活性显著减小(P<0.05),尤其是0—20cm土层;(3)微生物量碳氮与多酚氧化酶、蔗糖酶、脲酶、硝酸还原酶间呈极显著正相关(P<0.01);(4)多酚氧化酶与蔗糖酶、脲酶、硝酸还原酶呈极显著正相关(P<0.01),蔗糖酶与脲酶、硝酸还原酶呈极显著正相关(P<0.01),脲酶与硝酸还原酶呈极显著正相关(P<0.01);(5)研究表明土壤多酚氧化酶、蔗糖酶、脲酶与硝酸还原酶可敏感地反映植被过程中土壤质量的变化,植被恢复措施可改善表层与深层土壤的生物学性质。

In order to explore the effect of different vegetation restoration patterns on the soil microbial biomass and enzyme activity in process of desertification grassland management, this article selected alpine desertification grassland in northwest Sichuan as the study area and the desertification grassland without restoration as control （CK）. By measuring soil microbial biomass and enzyme activity under 3 vegetation restoration patterns, including fencing with sand-fixing barrier （WLCD）, fencing with sand-fixing barrier and grass seed （RGCD）, fencing with sand-fixing barrier and seeds of grass and oat （YMCD）, through field experiment and laboratory analysis, the change rule of soil microbial biomass and enzyme activity and their relationship were studied. The results indicated that： （1） Soil microbial biomass carbon （MBC）, soil microbial biomass nitrogen （MBN）, polyphenol oxidase, sucrase, urease and nitrate reductase activities under 3 kinds of vegetation restoration patterns, especially YMCD, were significantly higher than those in the grazing grassland （CK） （P〈0. 05）. Compared with CK, YMCD increased the contents of MBC and MBN, polyphenol oxidase, sucrase, urease and nitrate reduetase activities by 217. 52%, 725. 26%, 130.88%, 387. 78%, 300.33% and 192.32%, respectively. （2） The MBC,MBN, urease, suerase, polyphenol oxidase and nitrate reduetase activities significantly decreased with the increase of soil depth （P〈0.05）, especially in 0-20 cm layer. （3） There were significantly positive correlations between the contents of MBC and MBN and the activities of polyphenol oxidase, suerase, urease and nitrate reductase （P〈0.01）. （4） There were significantly positive correlations between the activities of polyphenol oxidase, suerase, urease and nitrate reductase （P〈0.01）. （5） Soil polyphenol oxidase, sucrase, urease and nitrate reductase activities could sensitively reflect the change of soil quality in the process of vegetation restoration, and vegetation restoration measures could improve the biological properties of surface and deep soil.