Emissions of CO2 and CH4 from Agricultural Soil with Kitchen Compost at Different Temperatures

Abstract

Emissions of CO₂ from the soil are mainly derived from soil microbial respiration, whereas CH₄ emissions originate from anaerobic degradation of organic matter via microbial processes. Kitchen waste compost is used in the agricultural sector to improve soil quality. However, abiotic CO₂ and CH₄ emissions from soils amended with kitchen waste compost under aerobic conditions remain uncertain. Temperature plays an important role in organic matter decomposition in both biotic and abiotic pathways. This study aimed to evaluate biotic and abiotic emissions of CO₂ and CH₄ from soils receiving kitchen compost at different temperatures. Ten grams of soil amended with or without 0.1 g kitchen compost (1%) were sterilized or non-sterilized. The mixture and soil-only samples were incubated in 100-mL glass bottles at 20, 30, and 35 °C for 28 d under an aerobic condition. The results showed that CO₂ and CH₄ emissions increased at higher temperatures and compost application rates (p < 0.05). Emissions of CO₂ mainly occurred via biotic pathways. Abiotic processes were potential pathways for CH₄ generation, particularly at high temperatures of 35 °C. There was 20–24% of C in kitchen compost changed to CO₂ and less than 0.1% to CH₄. Our results suggest that global warming enhances abiotic CO₂ and CH₄ emissions and may contribute to further global warming.