Carbon fixation, partitioning and storage in field planted with wheat (Triticum aestivum) at different moisture regimes

Impacts of agricultural management on soil organic carbon and soil carbon storage in fields planted with wheat at North East India are not well documented. Experiments were conducted to investigate the impact of water regimes on soil organic carbon and carbon storage in wheat grown alluvial soil of Assam. Continuous input of plant organic matter to soil through root exudation during the growth period of wheat variety ‘Sonalika’ was monitored in a twoyears field study. Carbon fixation and partitioning by the plants were estimated in terms of photosynthesis and biomass accumulation, respectively. Results demonstrate that there was increase in organic carbon at upper and lower depth of soil due to addition of crop root biomass. An average increment of 15.71% and 11.18% soil organic carbon at irrigated and rainfed conditions, respectively was recorded over the initial value during two years. Increment in net photosynthetic rate and higher dry matter accumulation was considered as the primary cause for higher grain productivity at irrigated condition.