Impact of Food Waste-Derived Compost with Varying Biochar Contents on Soil Carbon Dioxide (CO₂) Emissions
Moses Koomson *
Department of Soil Science, School of Agriculture, University of Cape Coast, Cape Coast, Ghana and Department of Agrobiotechnology, Institute of Agriculture, RUDN University, 117198, Moscow, Russia.
Obeng Dennis Ampofo
Department of Soil Science, School of Agriculture, University of Cape Coast, Cape Coast, Ghana.
Amakye Sheila Efua Anama
Department of Soil Science, School of Agriculture, University of Cape Coast, Cape Coast, Ghana and Department of Agrobiotechnology, Institute of Agriculture, RUDN University, 117198, Moscow, Russia.
Simbo Diakite
Department of Agrobiotechnology, Institute of Agriculture, RUDN University, 117198, Moscow, Russia.
*Author to whom correspondence should be addressed.
Abstract
Rising atmospheric carbon dioxide (CO₂) levels contribute significantly to global warming, with agricultural soils acting as both major sources and potential sinks for greenhouse gases (GHG). This study investigated the impact of food waste-derived compost amended with varying concentrations of coconut husk biochar on CO₂ emissions from highly weathered tropical soil. Biochar was produced via pyrolysis at 550 – 620°C and co-composted with domestic organic waste (cassava, plantain, and pineapple peels, and poultry manure) at ratios of 0%, 2%, 5%, and 10%. Six treatments, including an absolute control and inorganic NPK fertilizer, were applied to soil containers and incubated for 58 days. CO₂ emissions were quantified using sodium hydroxide (NaOH) trapping followed by hydrochloric acid (HCl) titration at intervals ranging from day 0 to day 58. Results indicated a significant reduction in emissions across all treatments after the initial incubation day. The Compost + 10% Biochar treatment consistently demonstrated the lowest CO₂ emissions (0.88 mg CO₂/day/kg on day 0), significantly outperforming the control (1.21 mg CO₂/day/kg), inorganic fertilizer, and lower biochar concentrations. By day 58, emissions across all treatments approached zero. The study concludes that amending food waste compost with 10% coconut husk biochar effectively suppresses soil CO₂ fluxes, acting as a carbon sink while enhancing soil fertility. This integrated organic management strategy offers a sustainable, climate-smart solution for reducing greenhouse gas emissions and promoting soil health in tropical agricultural systems.
Keywords: Biochar, biochar co- compost, NPK fertilizer, carbon dioxide emission, coconut husk, organic