Greenhouse Gas Emissions from Agricultural Soil Amended with Kitchen Compost of Varying Ages

Although the use of kitchen waste compost is very common, GHG emissions from soil amended with kitchen waste compost have not been studied. This study aimed to determine the effects of kitchen compost age and application rates on GHG emissions to identify optimal compost management. Soil samples mixed with kitchen waste compost at three different ages: 1 month (1M), 2 months (2M), and 3 months (3M) at two application rates (1% and 2% w/w) were incubated at 25°C for 28 days under aerobic conditions. Emissions of nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) were determined on days 3, 7, 14, 21, and 28. Results showed that N2O and CO2 emissions decreased with compost age (p < 0.05). Increased application rates of compost led to increased CO2 emissions and suppression of N2O emissions. Furthermore, CH4 was emitted from soil amended with kitchen compost even under aerobic conditions. This study suggests that 3M kitchen waste compost is optimal in terms of GHG emissions upon application to soil under aerobic conditions.