采用经典统计分析与排序分析,研究了2014—2018年岷江流域不同土地利用方式下(撂荒地、次生林、灌丛、果园和耕地)土壤微生物群落多样性变化特征,并探讨了其与土壤养分和土壤微生物数量之间的关系。结果 表明:(1)土壤pH值变化范围为6.13～7.02,其大小依次表现为撂荒地0.05),耕地最高(p次生林>灌丛>果园>耕地,不同土地利用土壤有效磷和有效钾差异均显著(p0.05)。(2)土壤微生物以细菌数目最多,占到90%以上,土壤细菌、真菌、放线菌和微生物总数目大小依次表现为撂荒地>次生林>灌丛>果园>耕地。(3)根据培养第100小时的AWCD值计算土壤微生物群落的物种丰富度指数(H)、均匀度指数(E)、优势度指数(Ds)和碳源利用丰富度指数(S)。土壤微生物多样性指数大小依次表现为撂荒地>次生林>灌丛>果园>耕地,不同土地利用均匀度指数(E)、优势度指数(Ds)差异不显著(p>0.05)。(4)相关性分析表明土壤养分、土壤微生物数量均与土壤微生物群落多样性具有显著的相关性(p<0.05),其中,土壤微生物数量对微生物群落多样性的贡献最大(其相关系数绝对值最大)。(5)冗余分析表明土壤微生物群落多样性与土壤养分含量均呈正相关(除了pH); 有机碳和全氮与丰富度指数相关性最大,由此可知,有机碳和全氮是影响该区土壤微生物群落多样性分布的主要因子。
The variation characteristics of soil microbial community diversity in different land use patterns(abandoned lands, secondary forests, shrubs, orchards and cultivated lands)in minjiang river basin from 2014 to 2018 were studied by using classical statistical analysis and sequencing analysis, and the relationship between them and soil nutrients and soil microbial quantity was discussed. The results showed that:(1)the pH value of the soil ranged from 6.13 to 7.02, and the pH values of the abandoned lands increased in the order: secondary forest0.05), and soil pH of the cultivated land was the highest (pshrubs>orchards>cultivated land>abandoned lands; the differences of available phosphorus and available potassium in different land uses were significant (p0.05);(2)the number of soil microorganisms was the largest, accounting for more than 90%; the total number of soil bacteria, fungi, actinomycetes and microorganisms decreased in the order: secondary forests>shrubs>orchards>cultivated land>abandoned lands;(3)species richness index(H), evenness index(E), dominance index(Ds)and carbon source utilization richness index(S)of soil microbial community were calculated according to AWCD value at 100 h; the soil microbial diversity index decreased in the order: secondary forests>shrubs>orchards>cultivated land>abandoned lands, no significant difference in the evenness index(E)and dominance index(Ds)was found (p>0.05);(4)correlation analysis showed that soil nutrients and soil microbial quantity were significantly correlated with soil microbial community diversity (p<0.05), among which soil microbial quantity contributed the most to microbial community diversity(with the largest absolute value of correlation coefficient);(5)redundancy analysis showed that soil microbial community diversity was positively correlated with soil nutrient contents; along the first sequencing axis of RDA, with the increase of significant influencing factors(soil nutrient indexes), the microbial richness index gradually increased, and the microbial richness index was negatively correlated with pH value; organic carbon and total nitrogen had the largest correlation with richness index, therefore, organic carbon and total nitrogen were the main factors affecting the diversity distribution of soil microbial community in this area.
