Carbon mineralization and carbon dioxide emission from organic matter added soil under different temperature regimes

Purpose Information on carbon dioxide (CO2) emissionfrom different organic sources and their temperature sensitivityto decomposition is scarce in Bangladesh. Therefore,this study quantified the rates of CO2 emission andcarbon (C) degradation constants from different organicmaterial mixed soils at variable temperatures in two laboratoryexperiments.Methods The first experiment was conducted at roomtemperature for 26 weeks to study CO2 emission and Cmineralization using vermicompost, chicken manure, cowdung, rice straw, and rice husk biochar. Weekly CO2emission was measured by alkali absorption followed byacid titration. The second experiment comprised two factors,viz. four organic materials (vermicompost, chickenmanure, cow dung, and rice straw) and six temperatureregimes (25, 30, 35, 40, 45, and 50 C). Organic materialsat 2.5 g C kg-1 soil were mixed in both experiments.Results CO2 emission reached the peak at 5th weeks ofincubation and then decreased with irregular fashion until21st week. The C emission loss followed in the order ofchicken manure[rice straw[vermicompost[cowdung[rice husk biochar, and C degradation constantsindicated the slower decomposition of rice husk biocharcompared to cow dung, vermicompost, chicken manure,and rice straw. Temperature positively enhanced the mineralizationof organic materials in the order of50[45[40[35[30[25 C, which contributed tohigher availability of soil phosphorus.Conclusions High temperature increased mineralization oftested organic materials. Because of slower decompositionrice husk biochar, cow dung and vermicompost applicationcan be considered as climate-smart soil managementpractices that might help in reducing CO2 emission fromsoil.