Effect of heat build-up on carbon emissions in chimato compost piles
A study was conducted to determine impacts of heat build-up of chimato compost piles TD0, TD20, TD40, TD50, TD60, TD80 and TD100, made by blending maize stalks with 0, 20, 40, 50, 60, 80 and 100% Tithonia diversifolia, respectively, on carbon losses and emissions during composting. Compost piles temperatures that determined heat built-up were obtained from previous studies. Organic carbon and total carbon of chimato composts were determined using Kjeldahl method. Relatively, greater carbon reductions were observed in compost piles TD0, TD20, and TD40 (that experienced prolonged high thermophilic temperatures (temperature >60°C)) than compost piles TD50 and TD60 (that experienced a short-lived thermophilic temperatures (45≤60°C)). The prolonged high temperatures increased kinetic energy of chemical species CO2 and CH4 that became more volatile and probably escaped from the compost piles in large quantities resulting in significant carbon emissions. Relatively, short-lived heat built-up in TD50 and TD60 resulted in minimal carbon reduction, hence minimal carbon emissions. Therefore, chimato composts TD50 and TD60 significantly reduce compost pile carbon emissions (p=0.05, ɑ=0.001) and should be recommended to mitigate effects of climate change.
Key words: Tithonia diversifolia, heat built-up, carbon emissions, carbon reduction, prolonged thermophilic temperatures.