Soil Carbon Dynamics, Sequestration and Productivity of Predominant Cropping Systems under Long Term (9 years) Inorganic and Organic Fertilization in Semi-Arid Deccan Plateau, India

Soil organic carbon (SOC) sequestration in agricultural soils is one of major agricultural strategies to mitigate the greenhouse gas (GHG) emissions as it is a potential sink for atmosphere carbon. Cropping systems and management practices adopted will affect the SOC sequestration. Dynamics of SOC is very important for understanding the pathways of C stabilization into different SOC pools. An attempt was made to assess the importance of different cropping systems on C sequestration and its stabilization in a 9 year old experiment at PJTSAU, Hyderabad, India. In comparison to initial TOC, cropping system perennial super napier fodder showed greater C build up (46.5%) followed by maize intercropped with pigeonpea followed by sunhemp (23.1%). In fact, all the cropping systems there were net increases in TOC. There was only 6.86% of C applied through various sources was stabilized as SOC. A minimal input of 1.24 Mg C ha-1 yr-1 is needed to maintain SOC level. Cropping system perennial super napier fodder showed a higher carbon management index (145.9), sustainable yield index (64.1), BC ratio (16.99) and least amount is required to sequester the kg of carbon to soil (Rs. 59).