Microbial Community, Biomass and Physico-Chemical Properties of Soil in dry tropics

Abstract Soil physicochemical and microbial properties can be regarded as an important tool to assess soil quality and health. Studying the soil properties under different land use types is great practical significant for land use and soil management regarding soil carbon dynamics and climate change mitigation. However, the changes in land-use types and their effects on soil physicochemical and microbial properties are largely debated and rather unclear. Four different land use types were used to study soil microbial and soil physico-chemical properties. Soil organic carbon and total nitrogen, soil microbial biomass and microbial diversity were determined by micro kjeldahl method, fumigation and extraction method and FAME GC-Ms, respectively. Among all land use pattern the highest water holding capacity (40.06±0.74%), porosity (0.539±0.011%), soil macro-aggregates (64.16±2.64%), organic carbon (0.84±0.054%), total nitrogen (0.123±0.013%), microbial biomass carbon (570.65±35.05 μg/g) and nitrogen (84.21±3.186 μg/g), basal respiration (3.64±0.064μg/g) and b-glucosidase (809.68±39.7μgμg PNP g-1 dry soil h-1) were found to be under natural forest followed by in decreasing order bamboo plantation, degraded forest and agricultural land. Significant differences were observed among the land use types with microbial biomass carbon and B-glucosidase activity. Furthermore, the correlation of analysis showed that microbial biomass, organic carbon, b-glucosidas activity, total nitrogen, moisture content, porosity, water holding capacity, soil macro aggregates were positively correlated to each other and negatively correlated with bulk density, meso and micro soil aggregates at p<0.05. The PLFA analysis showed that microbial community diversity exhibited distinct patterns among land-use types. The conversions of natural forest to other land use type, the amount of PLFA were reduced significantly. The natural forest had high microbial diversity followed by in decreasing order bamboo plantation, degraded forest and agricultural land. Among the organisms G- bacteria and fungi were showed decreasing order from natural forest, bamboo plantation, degraded forest and agricultural land. The reverse was true for G+ bacteria. The result of this study showed that soil physico-chemical and microbial properties were significantly affected by land use types. Thus bamboo based fallow has the potential for improving soil quality and properties in the short term.