Vol. 12, Issue 2 (2023)

Author(s):
Manoj M, BS Dhakad and Geeta Singh

Abstract:
The assessment of the impact of agri-management on the microbial activities related to C sequestration was undertaken using two contrasting long term (2003-2020) agricultural managements in the rice-wheat rotation. The aim was to assess the role of microbial glycoproteins for carbon sequestration in agricultural soil, Soil microorganisms are key agents determining the fate of soil C and aid in its sequestration. The organic management included input of a combination of nutrient sources farm yard manure (FYM), vermicompost (VC) and biofertilizers (BF) in the rice - wheat rotation. The treatment VC+CR+BF had significantly higher ergosterol, peroxidase, phenol oxidase, FDA hydrolase activity, β-glucosidase activity & Xylanase activity implying higher fungal populations that are active in the mineralization and subsequent loss of the soil C. while FYM+CR+BF had significantly higher, water-soluble phenolic content, SMBC at 0-30 cm soil depth. a high degree of homology of these microbial metabolites with the SOM indicates superiority of this treatment with its potential to increase the soil labile C fraction. The long-term conservation agriculture (Rice-Wheat rotation) experiments included Zero tilled direct seeded rice (ZTDSR) and zero tilled wheat (ZTW) along with moong bean and input of respective crop residues. These were compared with the farmers practice conventionally tilled rice and wheat (CTR – CTW). (MR + ZTDSR) – (RR + ZTW) – (WR + mungbean) had significantly higher ergosterol content & β-glucosidase activity. ZTDSR – ZTW had significantly higher peroxidase activity, glomalin content & water-soluble phenolic content, (WR + ZTDSR + BM) – (RR + ZTW)) had significantly higher phenol oxidase activity, MBC & xylanase activity with respect to (CTR – CTW). The (CTR – CTW) were dominated by aerobic microbial populations that accounted for the higher activities of oxidative enzymes resulting in loss of C as carbon dioxide. Zero tilled soils were found to aid the development of microbial community and their metabolites that are known precursors of recalcitrant C.