EVALUATION OF SOIL MICROBIAL BIOMASS CARBON AND NITROGEN DISTRIBUTION UNDER DIFFERENT AGRO-CLIMATIC CODITIONS

Abstract

Soil microbial biomass (SMB) is a chief marker of changes that may occur in soil fertility. It represents an important source and sink of nutrients and systematize the cycling of nutrients. The objective of the study was to determine soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN) and their correlation with selected physical and chemical properties. Selected soils with different land uses (cultivated, forest and grassland) and climatic conditions were Eutrudepts and Hapludolls. The forest soils of Eutrudepts and Hapludolls showed the highest amount of SMBC that was 265.01 mg / Kg in Eutrudepts. In Eutrudepts, SMBN was higher (48.713 mg / Kg) in forest soils while in Hapludolls statistically non-significant difference was observed among land uses. The SMBC and SMBN were positively correlated with soil organic matter (OM) (0.81 and 0.73), total N (0.62 and 0.59) and extractable K (0.51 and 0. 52) at Hapludolls. The same trend was observed at Eutrudepts. The SMBN and SMBC were lowest (30.48 and 136.18 mg /Kg) in cultivated land while, Hapludolls had higher SMBC (213.49 mg /Kg) than Eutrudepts (205.79 mg /Kg) and lower SMBN (40.18 mg /Kg) than Eutrudepts (42.45 mg /Kg) .