Carbon Dioxide Emission from Soil

Global warming and climate change are a cause for great concern demanding intensive research on CO2 emission from soil under different management options. Therefore, a pot experiment was conducted using 0.25 g C 100 g-1 soil from rice straw, rice root, cowdung, and poultry manure to quantify CO2 emission under alternate wetting and drying and continuously moist conditions. The maximum emission was recorded during the first week of incubation and after 3 weeks, it came down sharply and finally approached almost zero to 5 mg CO2 day-1 kg-1 irrespective of organic materials and water management. Among the organic materials, cowdung released less CO2 and increased carbon content in soil. During 118 days of incubation, cumulative emissions were 158, 313, 366, 283, 576 mg CO2 100 g-1 from soil, soil plus rice straw, soil plus rice roots, soil plus cowdung, and soil plus poultry manure, respectively. Alternate wetting and drying condition released more CO2 than that under continuously moist condition. Application of cowdung in agriculture can restrict CO2 emission. From the findings it could be apprehended that before application to soil, composting of organic materials through anaerobic digestion might be the best option to reduce CO2 emission, and thus help mitigate global warming. © 2013 NAAS (National Academy of Agricultural Sciences).