Dynamics of organic carbon in deep soils under rice and non-rice cropping systems

Subsoil might be a possible sink of stable C in some regions of India, which itself has low soil C storage. Further, knowledge of subsoil C chemistry under submerged rice ecology is required as rice is one of the major staple cereals in India and waterlogging influences SOC characteristics. This study investigated the dynamics of organic C in surface and deep subsoil layers under rice and non-rice ecology in eastern India. Outcomes revealed less organic C in deep subsoils (x 5.35 Mg ha(-1)), but with higher residence time as evidenced by a higher mean recalcitrant index (20.2) and lower mean lability index (1.86). Further, deep rice soils exhibited higher C sequestration potential than deep non-rice soils resulting from curbed microbial biomass and their activities. Summarily, deep rice soil exhibited the potential for C sequestration, displaying a synergistic effect from deep soil and submerged rice ecology. (c) 2016 Elsevier B.V. All rights reserved.