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以钱粮湖垸为例,研究了洞庭湖退田还湖区林地(Ⅰ)、园地(Ⅱ)、旱地(Ⅲ)、水田(Ⅳ)和荒地(Ⅴ)等不同土地利用方式下的土壤微生物数量、酶活性及其典范相关关系。结果表明:5种土地利用方式下不同土层细菌、放线菌数量均以旱地最高,真菌数量以荒地最高;细菌是土壤微生物的主要类群,占全部微生物的比例为44.42%～92.93%,其次为真菌数量,所占比例为4.89%～42.76%,放线菌数量最少,所占比例为1.71%～24.52%;不同土地利用方式下0～50cm土层磷酸酶、脲酶、蛋白酶和脱氢酶活性变化范围为0.01～0.07mg.g-1.d-1、0.01～0.05mg.g-1.d-1、0.92～7.11mg.kg-1.d-1和0.01～0.38μl.g-1.d-1;土壤磷酸酶、脲酶、脱氢酶活性分别以园地、荒地、水田最低,而旱地土壤蛋白酶活性总体最低;土壤微生物典范变量(U)中,放线菌数量与之呈正相关,回归系数最大(0.174),其次为细菌数量(0.003),而真菌数量则出现负相关(-0.215);土壤酶活性典范变量(V)中,脲酶活性与之呈正相关,回归系数最大(10.557),其次为脱氢酶活性(1.616),而磷酸酶活性(-17.275)与蛋白酶(-0.041)则出现负相关。不同层次土壤微生物数量及酶活性在典范变量上的聚集趋势可为该区域土壤健康诊断与立地类型划分提供依据。
Taking Qianlihu embankment as an example, this paper studied the soil microbial quantity under different land uses such as forest land (Ⅰ), garden land (Ⅱ), dry land (Ⅲ), paddy field (Ⅳ) and wasteland (Ⅴ) Enzyme activity and its canonical correlation. The results showed that the number of bacteria and actinomycetes in different soil layers were the highest in dryland and the highest in wildland in the five land use types. Bacteria were the main group of soil microorganisms, accounting for 44.42% -92.93% of the total soil microorganisms, followed by The number of fungi was 4.89% -42.76%, the least amount of actinomycetes, accounting for 1.71% -24.52%; in different land use types, the contents of phosphatase, urease, protease and dehydrogenase The activity ranged from 0.01 to 0.07 mg.g-1.d-1, from 0.01 to 0.05 mg.g-1.d-1, from 0.92 to 7.11 mg.kg-1.d-1 and from 0.01 to 0.38 μl.g- 1.d-1. The activities of soil phosphatase, urease and dehydrogenase were the lowest in field, wasteland and paddy field respectively, while the soil protease activity in dry land was the lowest. Soil actinomycete number was positively correlated with the soil microbial typical variable (U) , The regression coefficient was the highest (0.174), followed by the number of bacteria (0.003), while the number of fungi was negatively correlated (-0.215). The urease activity was positively correlated with the soil enzyme activity (V) ), Followed by dehydrogenase activity (1.616), while phosphatase activity (-17.275) was negatively correlated with protease (-0.041). The trend of aggregation of soil microbial quantity and enzyme activity on canonical variables at different levels could provide the basis for soil health diagnosis and site type classification in this area.