Greenhouse gas emissions from agricultural soil amended with kitchen compost of varying ages

ABSTRACT

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.

KEYWORDS:

• Aerobic conditions
• greenhouse gas emissions
• kitchen waste compost

Acknowledgments

We would like to thank Toshiaki Fukuda of the NPO Imari Hachigame Plan, Saga for providing compost, and the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) for providing a scholarship to the first author.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by JSPS KAKENHI Grant Number 20KK0147; and partially by a Cabinet Office grant-in-aid, the Advanced Next-Generation Greenhouse Horticulture by IoP (Internet of Plants), Japan; Research Grant for Encouragement of Students of Okayama University.