黑土区水土保持林对表层土壤微生物群落碳代谢多样性的影响

Effects of different soil and water conservation forests on topsoil metabolic functional diversity of soil microbial community in black soil region,northeastern China

采用Biolog-ECO微平板检测法，以典型黑土区美青杨林、水曲柳林、落叶松林和樟子松林土壤为对象，研究了不同类型水土保持林表层土壤（0～10cm）微生物群落碳代谢多样性的变化特征。结果表明：1）培养144h时，4种林地土壤碳源平均颜色变化率（AWCD）的变化范围为0．11—0．62，且表现为美青杨林最高，依次分别为水曲柳林和落叶松林，樟子松林最低；2）土壤微生物群落碳代谢多样性丰富度指数、Shannon—Winner指数、Simpson指数和McIntosh指数的变化范围分别为4～22、1．37～3．00、0．62—0．94和1．46—5．21，同样表现为美青杨林最高、其他依次分别为水曲柳林、落叶松林和樟子松林的规律；3）4种林地土壤微生物均以多聚物类为主要利用碳源，除此之外，阔叶林土壤微生物主要利用的碳源类型还包括氨基酸类和羧酸类；4）土壤微生物群落碳代谢多样性指标与土壤理化性质相关性极为密切。可以认为，阔叶林提高土壤微生物群落碳代谢多样性的作用优于针叶林，研究结果可为典型黑土区水土保持林的构建提供参考。

Metabolism diversity of soil microbial carbon sources in surface soil （0 -10 cm） from four soil and water conservation forests, dominantly composed of poplar （Populus nigra var. italica x P. cathayan） , Manchurian ash （Fraxinus mandshurica） , larch （Larix gmelinii） and Scots pine （Pinus sylvestris var. mongolica ） respectively, in typical black soil region of northeastern China was studied by using the method of Biolog ECO-microplate culture. Results showed that the average well color development （AWCD） varied from 0. 11 to 0.62 for four stands and the peak value was found in poplar, followed by Manchurian ash, larch and Scots pine, orderly. The microbial functional diversity showed the same changing tendency as AWCD, or poplar 〉 Manchurian ash 〉 larch 〉 Scots pine in consequence, with a variation range of 4 - 22, 1.37 - 3.00, 0.62 - 0.94, and 1.46 - 5.21 for richness index, Shannon- Weiner index, Simpson index and Mclntosh index, respectively. Polymers are main carbon sources for four forests, in addition to this, the soil microbes of broadleaved forests could also utilize amino acids and carboxylic acids as carbon sources with a higher efficiency and intensity. Based on the significant links between the metabolic diversity of microbial communities and soil physical and chemical properties, we conclude that broadleaved forest may have more metabolic functional diversity of soil microbial community than coniferous forest. The results presented in this paper could provide theoretical basis and reference for soil and water conservation forest construction in typical black soil region.