Microbial Community, Biomass and Physico-Chemical Properties of Soil in 1 Dry Tropics

10 Soil physicochemical and microbial properties can be regarded as an important tool to assess soil quality 11 and health. Studying the soil properties under different land use types is great practical significant for land 12 use and soil management regarding soil carbon dynamics and climate change mitigation. However, the 13 changes in land-use types and their eﬀects on soil physicochemical and microbial properties are largely 14 debated and rather unclear. Four different land use types were used to study soil microbial and soil 15 physico-chemical properties. Soil organic carbon and total nitrogen, soil microbial biomass and microbial 16 diversity were determined by micro kjeldahl method, fumigation and extraction method and FAME GC- 17 Ms, respectively. Among all land use pattern the highest water holding capacity (40.06±0.74%), porosity 18 (0.539±0.011%), soil macro-aggregates (64.16±2.64%), organic carbon (0.84±0.054%), total nitrogen 19 (0.123±0.013%), microbial biomass carbon (570.65±35.05 μg/g) and nitrogen (84.21±3.186 μg/g), basal 20 respiration (3.64±0.064μg/g) and b-glucosidase (809.68±39.7μgμg PNP g-1 dry soil h-1) were found to 21 be under natural forest followed by in decreasing order bamboo plantation, degraded forest and 22 agricultural land. Significant differences were observed among the land use types with microbial biomass 23 carbon and B-glucosidase activity. Furthermore, the correlation of analysis showed that microbial 24 biomass, organic carbon, b-glucosidas activity, total nitrogen, moisture content, porosity, water holding 25 capacity, soil macro aggregates were positively correlated to each other and negatively correlated with 26 bulk density, meso and micro soil aggregates at p<0.05. The PLFA analysis showed that microbial 27 community diversity exhibited distinct patterns among land-use types. The conversions of natural forest 28 to other land use type, the amount of PLFA were reduced significantly. The natural forest had high 29 microbial diversity followed by in decreasing order bamboo plantation, degraded forest and agricultural 30 land. Among the organisms G - bacteria and fungi were showed decreasing order from natural forest, 31 bamboo plantation, degraded forest and agricultural land. The reverse was true for G+ bacteria. The result 32 of this study showed that soil physico-chemical and microbial properties were significantly affected by 33 land use types. Thus bamboo based fallow has the potential for improving soil quality and properties in 34 the short term. 35

Soil physicochemical and microbial properties can be regarded as an important tool to assess soil quality 11 and health. Studying the soil properties under different land use types is great practical significant for land 12 use and soil management regarding soil carbon dynamics and climate change mitigation. However, the 13 changes in land-use types and their effects on soil physicochemical and microbial properties are largely 14 debated and rather unclear. Four different land use types were used to study soil microbial and soil 15 physico-chemical properties. Soil organic carbon and total nitrogen, soil microbial biomass and microbial 16 diversity were determined by micro kjeldahl method, fumigation and extraction method and FAME GC-17 Ms, respectively. Among all land use pattern the highest water holding capacity (40.06±0.74%), porosity 18 (0.539±0.011%), soil macro-aggregates (64.16±2.64%), organic carbon (0.84±0.054%), total nitrogen 19 (0.123±0.013%), microbial biomass carbon (570.65±35.05 μg/g) and nitrogen (84.21±3.186 μg/g), basal 20 respiration (3.64±0.064μg/g) and b-glucosidase (809.68±39.7μgμg PNP g-1 dry soil h-1) were found to 21 be under natural forest followed by in decreasing order bamboo plantation, degraded forest and 22 agricultural land. Significant differences were observed among the land use types with microbial biomass 23 carbon and B-glucosidase activity. Furthermore, the correlation of analysis showed that microbial 24 biomass, organic carbon, b-glucosidas activity, total nitrogen, moisture content, porosity, water holding 25 capacity, soil macro aggregates were positively correlated to each other and negatively correlated with 26 bulk density, meso and micro soil aggregates at p<0.05. The PLFA analysis showed that microbial 27 community diversity exhibited distinct patterns among land-use types. The conversions of natural forest 28 to other land use type, the amount of PLFA were reduced significantly. The natural forest had high 29 microbial diversity followed by in decreasing order bamboo plantation, degraded forest and agricultural 30 land. Among the organisms Gbacteria and fungi were showed decreasing order from natural forest, 31 bamboo plantation, degraded forest and agricultural land. The reverse was true for G+ bacteria. The result 32 of this study showed that soil physico-chemical and microbial properties were significantly affected by

60
Increasing evidence has shown that soil microbial attributes are potential early indicators of the 61 changes in soil quality because these parameters are more sensitive than are the chemical and 62 physical properties of soil.  Figure 2). Soil porosity (0.539%), soil aggregates and water holding capacity (WHC) (40.06%) 75 significantly higher in natural forest. However, soil moisture content and bulk density were 76 significantly higher in bamboo planation (2.78%) and agricultural land (1.37 g/cm 3 ), respectively 77 at p<0.05 (Fig 2). Soil aggregates, including macro-aggregates, meso-aggregates and micro-78 aggregates were significantly affected by land use types. Across different land use types, macro-79 aggregates constituted (42-64%) of total soil followed by meso-aggregates (25 to 33.6%) and 80 micro-aggregates (10-20%) ( In comparison to physical variables, strong and significant correlations were found between 117 chemical and biological variables. Microbial biomass carbon and nitrogen, b-glucosidase, 118 showed strong positive correlation with SOC, soil tN and macro soil aggregate; weakly 119 correlated to porosity, WHC and moisture contents. However, they were negatively correlated 120 with bulk density, soil meso and micro aggregates.  (Table 4).

133
This study demonstrated that land use change greatly impacted soil microbial community and  The reduction in WHC, porosity, moisture content and macro aggregates, and increase in bulk 148 density due to the conversion of natural forest to degraded forest and agricultural land (Fig 1).

149
Such trends were also reported by Singh  density of soil as compared to degraded forest and agricultural land (Fig 1). This is probably due

187
The metabolic activities of soil microbial communities under four different land use types was 188 quantified by measuring the amount of CO 2 produced or O 2 consumed in a given soil (Table 2).

189
The study found that natural forest was higher in soil BR while agricultural land was recorded  (Table 3). On average 95% of the microbial biomass and activities 220 were governed by the soil organic carbon, soil total nitrogen, water holding capacity, soil 221 aggregates, porosity and bulk density either positively or negatively (Table 4). The significant

242
The results of the present study showed that natural forest was highest in microbial diversity  Soil physico-chemical and biological properties were significantly affected by land use change.

259
Water holding capacity, porosity, soil macro-aggregates, soil organic carbon, and soil total 260 nitrogen were found to be higher in natural forest followed by in decreasing order bamboo and agricultural land (Fig 1).

280
The forest site was the mixed dry deciduous type dominated by Acacia catechu Wild.,