Gali, S.K.Roodagi, Mallikarjun2019-09-232019-09-232015-10http://krishikosh.egranth.ac.in/handle/1/5810128968A study was conducted during 2012-2013 at MARS, Dharwad and ARS, Prabhunagar to evaluate the soil organic carbon stocks (SOC) under selected tree plantations and agroforestry systems. The content of total carbon, soil organic carbon and its stocks in soils varied between the tree species and also two ecosystems viz., block plantations of trees and agro ecosystems and between Northern Transition (Zone-8) and Hill (Zone-9) of Karnataka. The amount of total carbon in soil, soil organic carbon and SOC stocks were highest in the soils under teak plantation at both the locations. The soil at ARS, Prabhunagar recorded higher values than the soil at MARS Dharwad. Among the block plantations of Dharwad, total carbon, SOC and SOC stocks were in the order of Teak > Mangium > Bamboo > Tamarind > Neem > Simarouba. But, at ARS, Prabhunagar, the three parameters were in the order of Teak > Sapota > Bamboo > Simarouba. Comparison between the two ecosystems at MARS, Dharwad highlighted, soils under block plantations had much higher SOC stocks than those of agroforestry systems. In the agroforestry systems, soil of neem AFS recorded highest SOC and SOC stocks followed by pongamia AFS and sapota AFS. Due to the improvement in soil organic carbon, physical properties like water holding capacity and water stable aggregates improved under different tree covers while, bulk density decreased. There was slight decrease in the pH of soil under tree covers, whereas no appreciable change in EC was observed. The organic matter fractions viz., humic acid and fulvic acid contents, available macronutrients, micronutrients, labile carbon, water soluble carbon, dehydrogenase and phosphatase activities were higher under tree plantations and agroforestry systems. The benefits of growing trees as a component of annual crops in the agroforestry ecosystems in sequestering atmosphere carbon was quite evident from the study.ennullThesis