Laboratory Incubation Studies of Biochar Amendment on Non - Co2 Greenhouse Gas Emissions from Soil Cultivated to Coconut Seedlings

Biochar is a carbon-rich product obtained when biomass such as wood, manure or leaves is heated in a closed vessel with little or no air. It is an appropriate tool for sequestrating carbon dioxide in soils for a long time in order to mitigate climate change. The objective was to determine the effects of biochar amendment on greenhouse gas emissions from soil cultivated to the coconut seedlings. The palm fronds biochar produced at 300oC for three hours was characterized in terms of pH, attrition, porosity, bulk density, ash content, conductivity, surface charge, nutrient value, yield% and surface area. Soil samples collected were prepared and analyzed for Physico-chemical properties in the laboratory using standard techniques. Glass jars (5L) with air-tight lids filled with 1.5kg dry wt soil, biochar at a variable rate of (10-50)t dry biochar ha–1, and mesocosms were maintained in the dark at 23°C. Jars were sealed for 24 hours prior to headspace gas sampling. NH3, CH4, N2O emissions, soil pH, cation exchange capacity (CEC), potassium (K) availability, and water retention in the soil were determined. Emission of N2O-N ranged from 12 to 1255 µ g N m-2, hr-1 during 148 hours of the studies. The flux of CH4 varied between 20 to 100 g CH4 m-3, hr-1, however, an increased sink of CH4 flux in the soil was observed in the treatments. Biochar addition to the soil also caused reduced ammonification compared to the control The Physico-chemical properties of the biochar–soil mixture samples showed significant (p<0.05) improvement.