Effect of vegetation type and season on microbial biomass carbon in Central Himalayan forest soils, India

Soil microbial biomass is an important component of soil organic matter constituting from 2 to 5% of the soil organic carbon and play a significant role in the cycling of nutrients and overall organic matter dynamics. The present study assessed the effects of three forest types (Banj-oak forest, Chir-pine forest and Mixed oak-pine forest) on the soil physico-chemical properties and microbial biomass Carbon in Central Himalaya, India. The soil microbial biomass carbon was determined by chloroform fumigation extraction method. In the 2 year of study period, the soil microbial biomass carbon (C-mic) was significantly higher in Mixed oak-pine forest (681 +/- 1.81-763 +/- 1.82 mu g g(-1)) than in the Banj-oak (518 +/- 1.50-576 +/- 1.73 mu g g(-1)) and Chir-pine forest (418 +/- 1.42-507 +/- 2.05 mu g g(-1)). Though insignificant, all the forest types showed distinct seasonal variations in microbial biomass carbon with a minimum value in winter season and maximum value in rainy season. The soil microbial quotients (C-mic to C-org) were higher in Chir-pine (2.52-4.18) and Banj-oak forest (2.26-4.02) than those reported in Mixed oak-pine forest (1.44-2.24). These results indicate that Mixed oak-pine forest is better in sustaining the soil microbial biomass and soil nutrients than Banj-oak and Chir-pine forest. It recommends that nutrients rich Mixed oak-pine forest should be preferred as a forest management practice to promote microbial diversity, their activities and soil quality enhancement in Central Himalayan forests.