Seasonal changes in soil microbial biomass under different agro-ecosystems of Arunachal Pradesh, North East India

Abstract

The study was carried out to investigate the soil microbial biomass C, N and P of major agro-ecosystems prevalent in East Siang district, Arunachal Pradesh viz., Soybean, Millet, Maize and Vegetable agro-ecosystem. The study was conducted for a period of an annual cycle during the year 2010-11. Microbial biomass C and N ranged between 199.61 and 238.35 µg g -1 and 15.46 and 26.55 μg g -1 respectively. It was found to be higher in the surface soil layer than the subsurface layer in all the agro-ecosystems. Microbial biomass P significantly varied among the seasons and sites (P<0.05). Microbial C/N ratio was found to be higher in subsurface soil layer than the surface soil layer and the ratio varied between 8.83 and 13.94 in all the sites. Microbial biomass C contribution to total soil organic carbon was 1.13%-3.37%. Microclimatic variations and different agricultural practices were found to affect the changes in microbial biomass.