Spatial variation of soil organic carbon stock in a typical agricultural farm of hot arid ecosystem of India

Abstract

Soil organic carbon (SOC) is the largest among three major carbon pools of global ecosystems. During the past few years, global warming and forcible land-use changes have resulted in a huge loss of this major carbon pool and as a consequence, concentration of atmospheric CO2 has increased. To mitigate the potential risks arising from atmospheric abundance of CO2, adoption of carbon sequestration strategies at different landscape scales is a major option. For this purpose, proper estimates of SOC stock per unit area are essential. In this study, we have estimated the SOC stock of a typical agricultural farm from hot arid ecosystem of India and also its spatial variation within the farm. The surface map of the SOC stock revealed that introduction of cultivation practices in fragile lands of the desert region has resulted in huge depletion of soil carbon. For example, the SOC stock of 10- years cultivated plots was found to be almost half of the SOC stock of recently cultivated plots of the farm. The results also showed that previous reports on large-scale estimates of SOC stock for hot arid region of India do not match with the current estimate from a farm scale of the same region. Consideration of spatial variation of SOC during calculation of SOC stock has helped us prepare a surface map of SOC stock of the farm, which may further be used as an essential requirement for implementation of site-specific carbon sequestration strategies and proper carbon credit programmes in the agricultural farms of India.