R. LALFAKZUALA, H. KAYANG AND M. S. DKHAR
Abstract
Soil microbial biomass carbon (Cmic) was measured under the cultivation of a high yielding variety of groundnut ICGS-76 (Araclzis lzypogaea L.) treated with inorganic and organic fertilizers at an upland experimental block of Agronomy division, Indian Council of Agricultural Research (ICAR)Barapani Shillong, Meghalaya, India. Soil samples were collected randomly at monthly intervals during two crop cycles from each different treatment at two-depths (0-10 cm and 10-20 cm). At the surface soil laver, the maximum Cmk (1061.2 j,g C g-' dry soil) was observed at NPK-i-FYNI plot, whereas the minimum C,:, (42.5 \ag C g-1 dry soil) was observed at FYM plot. At the subsurface soil layer, peak microbial biomass carbon (817.7 I j.g C dry soil) was observed at NTK-FFYM plot, whereas the minimum (16.2 tj,g C g- dry soil) was observed in FYM plot. Insignificant differences in C . were found among the treatments at both the surface and subsurface soil layers. The significant variation was obtained in microbial bion-iass carbon between surface and subsurface soil layers except only in NPK+FYM plot. Microbial population and total organic (TOC) carbon showed a significant correlation with Cink at surface and subsurface soil layers. The investigation showed that Cinic increased shortly after the application of fertilizers and inconsistent distribution of C each treated plots. Fertilizers application has lowered the amount. of Cmic as compared to the non-agricultural field soil. Surface soil layer showed higher accumulation microbial biomass carbon than the subsurface soil layer.