DYNAMICS OF SOIL MICROBIAL BIOMASS UNDER DIFFERENT LAND USES IN SOUTHERN GUINEA SAVANNA ZONE OF NIGERIA

Abstract

Management practices and vegetation exert a profound influence on microbial biomass carbon and nitrogen. This study was carried out to estimate microbial biomass carbon and nitrogen at three soil depths (0-5cm, 5-10cm and 10-15cm) and in relation to physico-chemical properties of the soils under four land uses (Teak, gmelina , cashew and fallow soil) in Minna, Niger State. The experiment was a 4 x 3 factorial in Randomized Complete Block Design (RCBD). Soils under teak had the highest microbial biomass carbon (1347.3 mg kg-1) followed by soils under gmelina (1281.1 mg kg-1), fallow (1032 mg kg-1,) and cashew (678.2 mg kg-1) in that order. On the other hand, soils under gmelina (13.569 mg N kg-1) and cashew (9.647 mg N kg-1) had the highest microbial biomass nitrogen, followed by those of fallow (8.9873 mg N kg-1) and teak (6.778 mg N kg-1). Both microbial biomass C and N were significantly affected by soil depth with the 0-5cm depth having the largest amount. This study showed that land use has a significant effect on microbial biomass C and N in soil by altering natural soil characteristics.