IMPACT OF LONG TERM TILLAGE AND RESIDUE APPLICATION ON ORGANIC CARBON POOLS AND CARBON STOCK IN SEMI ARID TROPICAL ALFISOL OF HYDERABAD

Not Availablelong term experiment was conducted in rainfed semi-arid tropical Alfisol at Hayathnagar Research Farm of Central Research Institute for Dryland Agriculture, Hyderabad, India, during the period 1995 to 2013 to study the long-term impacts of tillage and residue application on carbon sequestration, C pools and C Management Indices and their relationship with crop yield. The experiment was conducted in a split-split plot design with conventional tillage (CT) and minimum tillage (MT) as main factors, surface application of sorghum stover @ 2t ha-1 (SS), fresh gliricidia loppings @ 2t ha-1 (GL) and ‘no’ residue (NR) as sub factors and levels of N viz., 0 (N0), 30 (N30), 60 (N60) and 90 (N90) kg N ha-1 as sub-sub factors in a castor-sorghum yearly rotation. The results of the study clearly indicated that minimum tillage significantly increased the contents of soil C pools viz., microbial biomass carbon, labile carbon and its fractions and particulate organic carbon compared to conventional tillage. It was also observed that significant inter-correlations existed among the carbon pools studied which indicated a dynamic equilibrium with each other. Of all the treatment combinations studied, the practice of minimum tillage coupled with application of Gliricidia loppings @ 2t ha-1 and nitrogen applied @ 90 kg ha-1 (MTGLN90) was found to be the most promising in terms of maintaining significantly higher carbon stock in semi arid tropical Alfisols.Not Availabl