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Abstract:
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Soil microorganisms play a main part in organic matter decomposition and are consequently necessary to soil ecosystem
processes maintaining primary productivity of plants. In light of current concerns about the impact of cultivation and climate
change on biodiversity and ecosystem performance, it is vital to expand a complete understanding of the microbial community
ecology in our soils. In the present study we measured the depth wise profile of microbial load in relation with important soil
physicochemical characteristics (soil temperature, soil pH, moisture content, organic carbon and available NPK) of the soil
samples collected from Mahatma Gandhi University Campus, Kottayam (midland region of Kerala). Soil cores (30 cm deep)
were taken and the cores were separated into three 10-cm depths to examine depth wise distribution. In the present study,
bacterial load ranged from 141×105 to 271×105 CFU/g (10cm depth), from 80×105 to 131×105 CFU/g (20cm depth) and from
260×104 to 47×105 CFU/g (30cm depth). Fungal load varies from 124×103 to 27×104 CFU/g, from 61×103 to110×103 CFU/g
and from 16×103 to 49×103 CFU/g at 10, 20 and 30 cm respectively. Actinomycetes count ranged from 129×103 to 60×104
CFU/g (10cm), from 70×103 to 31×104 CFU/g (20cm) and from 14×103 to 66×103 CFU/g (30cm). The study revealed that there
was a significant difference in the depthwise distribution of microbial load and soil physico-chemical properties. Bacterial,
fungal and actinomycetes load showed a decreasing trend with increasing depth at all the sites. Except pH all other
physicochemical properties showed decreasing trend with increasing depth. The vertical profile of total microbial load was well
matched with the depthwise profiles of soil nutrients and organic carbon that is microbial load was highest at the soil surface
where organics and nutrients were highest |