Influence of Chinese herbal plants on greenhouse gas emissions from pig manure composting and fermentation

Abstract

To reduce greenhouse gas emissions during the composting of animal manure and promote the resource utilization of Chinese herbal plants, experiments on pig manure composting were conducted in a plastic greenhouse. A mixture of herbal powders (Radix isatidis and Radix Polygoni Multiflori, mixed in a 1:1 ratio) was added to the pig manure at concentrations of 0.05%, 0.1%, and 0.5% (w/w), respectively. The results showed that the emission peaks of greenhouse gases occurred in the early stages of composting. The addition of 0.5% of a mixture of Chinese herbal plant powders resulted in a significant reduction in cumulative emissions of CO₂ (45.0%) and N₂O (60.0%) compared to the control. This treatment also resulted in the lowest global warming potential, measured at 91.3 g kg⁻¹, and significantly increased the germination index. The study concluded that adding 0.5% Chinese herbal plant powder to compost effectively mitigated greenhouse gas emissions during the composting process.