利用变性梯度凝胶电泳和Biolog_Eco生态培养平板技术,调查了喀斯特自然退耕(NT，撂荒)、人工种植经济林(CM，木豆-板栗)、免耕(PI，牧草-任豆)和传统耕作(MB，玉米-大豆)4种退耕模式下的土壤微生物遗传分类和土壤细菌代谢功能多样性.结果表明:退耕模式显著影响了土壤微生物群落结构和细菌代谢模式, 其中真菌群落更依赖于退耕模式,而细菌群落对季节变迁更敏感;短时期(6～7年)不同退耕模式下土壤中细菌遗传分类多样性没有显著性差异(P>0.05),经济林与牧草地土壤真菌遗传分类多样性显著高于撂荒和传统耕作地(P<0.05);免耕牧草地土壤细菌代谢功能多样性显著低于其他模式(P<0.05).因此,真菌遗传多样性和细菌代谢多样性较细菌遗传多样性对退耕模式响应更敏感;土壤细菌群落对季节的变化比真菌敏感;木豆板栗经济林对维持土壤微生物遗传和细菌代谢功能多样性具有优势,是较好的退耕模式.
By using denaturing gradient gel electrophoresis (DGGE) and Biolog_Eco micro-plate technique, this paper studied the soil microbial genetic taxonomic and bacterial metabolic functional diversities under four de-farming patterns, i.e., natural restoration (NT, dominant plant species Neyraudia reynaudiana and Miscanthus floridulus), economic plantation (CM, Cajanus cajan and Castanea mollissima), zero-tillage (PI, Pennisetum purpureum and Zenia insign), and conventional tillage (MB, maize-soybean intercropping), in a typical Karst peak-cluster depression. All test de-farming patterns had significant effects on the soil microbial community structure and bacterial metabolic pattern. The community structure of soil fungi was more affected by the de-farming patterns than that of soil bacteria, while the later was more affected by seasonal variation. After 6-7 years of de-farming, soil bacterial taxonomic Shannon diversity indices had no significant differences under the four de-farming patterns, while soil fungal taxonomic Shannon diversity indices were significantly higher under CM and PI than under NT and MB. The soil bacterial metabolic functional diversity under PI was obviously lower than those under other de-farming patterns. Therefore, soil fungal genetic and bacterial metabolic diversities were more sensitive to de-farming patterns than soil bacterial genetic diversity did. Among the four defarming patterns, economic plantation had the superiority in maintaining soil microbial genetic and bacterial metabolic functional diversities, being a better de-farming pattern.