【摘要】 为了探讨黄土丘陵区自然植被恢复过程中土壤微生物学质量演变特征,用时空互代法对燕沟和县南沟典型小流域自然植被恢复下5个演替阶段(退耕1~6a、7~17a、18~35a、36~60a、>60a)土壤养分含量、微生物量和酶活性进行了研究。结果表明:随着地区植被退耕后自然演替的推进,土壤有机碳、全氮、有效氮与有效钾含量持续增加,土壤全磷含量在不同植被演替阶段变化不明显,有效磷含量在植被演替至多年生草本阶段(18~35a)时含量最低;土壤细菌约占土壤微生物量的65%左右,且其数量在植被演替至多年生草本阶段时最多,土壤真菌和放线菌随退耕年限的延长呈现不断增加的趋势;土壤碱性磷酸酶、脲酶和蔗糖酶活性也随着植被自然演替的推进呈不断增加趋势,但脲酶和蔗糖酶在植被演替至灌木阶段(36a)后增速放缓。相关性分析表明,自然恢复过程中土壤微生物数量与酶活性的提高程度比较一致,其与土壤养分关系密切,因此土壤微生物群落与土壤酶活性是反映植被恢复中土壤生物学质量变化的重要指标。更多还原

【Abstract】 In order to investigate evolution characteristics of soil biological property in loess hilly region during the process of natural vegetation restoration,soil nutrient content,microbial biomass and enzyme activities of the five natural vegetation successional stages(abandoned time 1~6a,7~17a,18~35a,36~60a,>60 a)were studied by using spatio-temporal substitution method in Yangou and Xiannangou watershed.The results showed that soil organic carbon,total nitrogen,available nitrogen and available potassium increased during the natural process of vegetation succession after stop of cropping,but there was no significant difference for the contents of soil total phosphorus in different succession phases.The content of available phosphorus was the lowest during the vegetation succession progress of perennial herb stages(18~35a).The amount of soil bacteria accounted for about 55% of soil microbial biomass during the natural vegetation succession of 18~35a,there were more soil bacteria than at other stages.The amount of soil fungi and actinomycetes showed a rising trend with the development of vegetation succession.And the activity of soil alkaline phosphatase,urease and invertase increased with the advance of vegetation succession.However,the increase rates of activity of urease and invertase decreased after 36a.The result of correlation analysis showed that the amount of soil microbes were consistent with soil enzyme activity in natural restoration process of a-bandoned farmland,and had a close relationship with soil nutrient.Soil microbes and enzyme can be chosen as biological indicators to evaluate soil biological quality during the process of natural vegetation restoration.更多还原