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土壤微生物和土壤酶作为土壤生态环境最重要的组成成分,对环境变化敏感.本文以缙云山柑橘林为研究对象,采用磷脂脂肪酸法并结合主成分分析方法,分析季节更替对柑橘林土壤表层(0~20 cm)的土壤微生物数量、群落结构特征及酶活性等的影响.结果表明:1季节更替对土壤微生物有显著影响(P<0.05),16:0、i17:0、16:1 2OH、18:0、cy19:0ω8c、i17:1ω9c或16:0 10-methyl为4个季节共有PLFAs,含量之和分别占PLFAs的49.57%、41.63%、35.41%和38.05%.各微生物种类中,细菌PLFA比例最高,其次为真菌PLFA,放线菌PLFA比例最低,且均具有显著的季节变化特征,柑橘林土壤PLFAs总量变幅为6.868~24.085 nmol·g-1,大小顺序为春季>秋季>冬季>夏季,细菌PLFAs、G-、G+及放线菌PLFAs也呈现一致的变化规律,但真菌PLFAs则表现为秋季最高,其次是冬季和夏季,春季最低.季节更替对微生物群落多样性指数亦产生显著影响,丰富度指数(R)随季节变化依次为春>冬>秋>夏,多样性指数(H’)随季节变化表现出冬>秋>春>夏,均匀度指数(J)表现为夏>秋>冬>春,优势度指数(D)则随季节表现为直线升高的变化趋势.2土壤脲酶随季节变化表现为夏季>春季>秋季>冬季;土壤蔗糖酶、土壤过氧化氢酶和酸性磷酸酶活性随季节变化均表现为秋季最高,其次是春季、夏季,冬季最低.3主成分分析结果表明细菌PLFAs、G+、G-、放线菌PLFAs和总PLFAs对土壤肥力贡献最大,其次是蔗糖酶、过氧化氢酶、酸性磷酸酶和真菌PLFAs,贡献最小为脲酶.
Soil microorganisms and soil enzymes are the most important components of soil ecological environment and are sensitive to environmental changes.In this paper, citrus groves in Jinyun Mountain were taken as research objects, and phospholipid fatty acid method and principal component analysis were used to analyze the effects of seasonal alternations on soil surface layer (0 ~ 20 cm) of soil microbial biomass, community structure and enzyme activity, etc. The results showed that: 1 seasons alternation had a significant effect on soil microbe (P <0.05), 16: 0, 17: 0, 16: The total content of PLFAs was 49.57%, 41.63%, 35.41% and 38.05% of the total PLFAs at 18: 0, cy19: 0ω8c, i17: 1ω9c or 16: PLFA was the highest, followed by fungi PLFA and actinomycetes PLFA, all with significant seasonal variation. The total PLFAs amplitude of citrus groves varied from 6.868 to 24.085 nmol · g-1 in order of spring> autumn> In winter and summer, the PLFAs, G-, G + and PLFAs of actinomycetes also showed consistent changes, but the fungi PLFAs showed the highest in autumn, the lowest in winter and summer, and the lowest in spring. The diversity index Have a significant impact, richness The number (R) followed the seasons as follows: spring> winter> autumn> summer. The diversity index (H ’) showed seasonal change in winter> autumn> spring> summer. > Spring, the dominance index (D) showed a trend of linear increase with the seasons.2 Soil urease showed seasonal changes in summer> spring> autumn> winter; soil invertase, soil catalase and acid phosphatase The activity changes with seasons are highest in autumn, followed by spring, summer and winter.3 The results of principal component analysis showed that PLFAs, G +, G-, actinomycetes PLFAs and total PLFAs contributed most to soil fertility, followed by sucrase , Catalase, acid phosphatase and fungi PLFAs, contributed the least to urease.