[Soil microbial diversity in typical Karst peak-cluster depression under effects of different de-farming patterns]

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 de-farming patterns, economic plantation had the superiority in maintaining soil microbial genetic and bacterial metabolic functional diversities, being a better de-farming pattern.