Effects of land-use change on soil microbial C, N and P in a Himalayan watershed

Soil microbial C, N and P as affected by land-use change were studied in a Himalayan Microbial biomass; watershed at Sikkim, India. The major land-uses considered were forests (dense and Mamlay watershed; open), agroforestry types (Large cardamom and mandarin), open cropped and Soil properties; wasteland areas covering subtropicat and temperate zones. Across the land-use, Sikkim Himataya microbial C ranged from 219 to 864 mug g(-1), microbial N from 30 to 142 mug g(-1), and microbial P from 12 to 43 mug g(-1) soils. The microbial C, N and P were positively related to each other. The microbial C:N ratio in these soils ranged from 6 to 11 and the microbial C:P ratio from 18 to 27. The conversion of forests into other land-uses resulted in a remarkable decline in the amounts of soil nutrients and microbiat C, N and R The microbiat nutrients in the Himalayan region are very sensitive to land-use/cover changes. Therefore, the conversion of forest to agricultural land should be reversed. Agroforestry systems should be included in agricultural land in mountainous regions. (C) 2003 Elsevier GrnbH. All rights reserved.