Soil microbial activities and its relationship with soil chemical properties under selected soil management systems

Abstract

Most studies in agricultural soil management systems have focused on soil physico-chemical parameters with less on the soil microbial attributes and activities. The aim of this study was to evaluate the microbial activities of soils under selected soil management systems. A total of 75 soil samples were collected in each of year 2012 and 2015 from three fields having different management systems. The fields assessed are organically managed Soils (OMS), Inorganically Managed Soils (IMS) and an Uncultivated Land having grass coverage (ULS). Soil Microbial Respiration (SMR), Microbial Biomass Carbon (MBC), Microbial Biomass Nitrogen (MBN) and Microbial Biomass Phosphorus (MBP) were analyzed. Soil chemical properties were also analyzed using standard procedures. The results showed a substantial difference in the microbial activities, in terms of soil management in both years. Soil microbial activities were highest in OMS as observed in SMR (11.34 μgCO₂-Cg^-1h^-1), MBC (347.9 μgCg^-1), MBN (32.84 μgNg^-1) and MBP (15.35 μgPg^-1), while IMS had the lowest microbial activities of SMR (4.56 μgCO2-Cg^-1h^-1), MBC (144. 2 μgCg^-1), MBN (12.39 μgCg^-1) and MBP (6.60 μgCg^-1) in both years. Between 2012 and 2015, MBC which is one of the key indicators of soil quality and thus sustainable soil management, showed an increase of 61.4%, 32.5% and 42.2% in OMS, IMS and ULS respectively. The results suggest that soil management systems which employ the use of organic inputs may be a more efficient means of improving soil microbial activities and soil fertility.

Keywords: Microbial activity; soil management; chemical, organic; inorganic