Influence of prevailing disturbances on soil biology and biochemistry of montane habitats at Nanda Devi Biosphere Reserve (NDBR), India during wet and dry seasons

The impact of prevailing disturbances in montane habitats of Nanda Devi Biosphere Reserve (NDBR) was studied on soil microbial population, biomass, soil respiration and enzyme activities during wet and dry seasons. The physico-chemical characteristics of soils exhibited conspicuous variation in total carbon and nitrogen content; being maximum in grazed meadow soil in wet season and minimum in intact forest soil in dry season. The rate of N-mineralization and nitrification was maximum (31.5 μg g− 1 day− 1 and 10.3 μg g− 1 day− 1) in grazed meadow soil during wet season and minimum (9.7 μg g− 1 day− 1 and 4.8 μg g− 1 day− 1) in intact forest soil during dry season. The bacterial and fungal populations were also highest in grazed meadow soil followed by disturbed forest, residential area and lowest in intact forest soil, especially in wet season. The soil respiration and enzyme activities (dehydrogenase and alkaline phosphatase) were found maximum in grazed meadow soil during wet season and minimum in intact forest soil during dry season. Correlation analysis among variables at different sites revealed significant and positive correlation among soil organic matter, microbial biomass and activities, emphasizing ‘successional effect’ on health and fertility status of soil.

Research highlights
► Soil's physico-chemical characteristics exhibit conspicuous variation among habitat.
► The microbial populations and enzyme activity were highest in grazed meadow soil.
► Positive correlation among variables showed ‘successional effect’ on soil health.
► All soil characteristics were higher in wet season than dry season, except NO3-N.
► Soil micro flora and activities greatly affected by prevailing disturbances.