Spatial Heterogeneity Of Soil Microbial Biomass In Sloping Farmland In A Karst Region On The Yunnan-Guizhou Plateau

Soil microbes to promote energy flow and material cycling in ecosystem, maintaining the normal functioning of the ecosystem is an important part in the ecosystem, their distribution in the soil both reflect a combination of factors including soil, vegetation and climate of microorganisms and role in their life activities also reflects the close relationship of soil fertility, soil improvement status and plant nutrition,.and is generally considered to reflect the important early warning and sensitive indicators of soil ecosystem changes. Southwestern karst region of the fragile ecological environment, strong degradation of the ecosystems in excessive human interference, natural disasters, and rocky desertification phenomenon day by day was the ever-expanding trend, a serious impediment to the sustainable development of the region away. It is important to study the characteristics and the spatial patterns of soil microbes for the rebuilding and restoring of Karst ecosystems. We chose an typical sloping farmland in a Karst region on the Yunnan—Guizhou plateau, and to examine the spatial patterns of soil microbes by sample survey and experimental analysis. We used typical statistics method to describe the characteristics of soil microbes, and applied the geo-statistics method to discuss the spatial patterns of soil microbes, and used path analysis to discuss the relationship between soil microbes and soil nutrients. The main conclusions are as follows:(1) Soil microbial biomass in typical sloping farmland in a Karst region on the Yunnan—Guizhou plateau compared with the same type of farmland soil, its MBC, MBP content were relatively modest, but low MBN content. In addition, soil microbial3groups in addition to Actinobacillusnumber of bacteria outside the low, the proportion of bacteria with the previous study,3groups of total bacterial consistent results, the largest number of karst soil in sloping actinomycetes, while the proportion of bacteria and fungi compared with low, as follows:actinomycetes> bacteria> fungi.(2) Geostatistical analysis showed that the traditional hypothesis of random distribution and soil microorganisms, the Yunnan-Guizhou Plateau karst slope farmland soil microbial spatial distribution of the obvious characteristics of the soil microbial indicators were shown a different spatial pattern, which restricts the distribution of impact factors are mainly topography, parent material, soil properties, and other structural factors. The range was small, and the spatial heterogeneity was strong.(3) Soil microbial biomass C, N showed strong correlation in sloping farmland in a Karst region on the plateau, the correlation between soil microbial biomass C,P was not obvious, but between the soil microbial biomass N,P has strong correlation. The number of soil microbial3groups showed strong correlation between each other, but between soil microbial biomass and microbial3groups was no obvious correlation except the soil microbial biomass C and actinomycetes showed a strong correlation.(4) Different soil nutrient factors had different effects on soil microbial indicators. Soil microbial biomass C,N and the SOM,TK,TN,AK,AN was a strong correlation, and the soil microbial biomass N also showed a strong correlation with soil PH; soil microbial biomass P and the SOM,TK,TN,the AN was a strong correlation, and correlation with SOM performance is strong. soil microbial3groups in sloping farmland in a Karst region on the plateau has a weak correlation with soil nutrient factors.