Soil carbon sequestration is a process in which CO2 is removed from the atmosphere and stored in the soil carbon pool. This process is primarily mediated by plants through photosynthesis fixing atmospheric CO2 into standing biomass (crops or trees) and root biomass, which leads to carbon stored in the form of soil organic carbon (SOC). Soils of native forests have a large carbon storage capacity and can act as net sinks for atmospheric CO2.
The carbon sequestration potential of soils of orchards and agro-forestry ecosystems having different age group of plants maintained under different agronomical practices like application of various soil amendments (organic, bio-dynamic and conventional), crop rotation, intercropping etc. have been evaluated. The predominant observation is that there was a gradual increase in soil carbon content with increasing age of the plant (5 to 20 years). Furthermore, the organic farming system in particular, was found to influence storage of CO2 as organic carbon in the soils of orchards in all climatic zones and also enhanced the microbial diversity in soil. A typical 20-year orchard and agro-forestry ecosystem maintained under organic farming practices was observed to store carbon averaging 694 equivalent CO2 (t ha–1) as standing biomass.