Ammonia Volatilization and Greenhouse Gases Emissions during Vermicomposting with Animal Manures and Biochar to Enhance Sustainability

Abstract

There is a huge potential for nutrient recovery from organic waste materials for soil fertility restoration as well as negative environmental emission mitigation. Previous research has found vermicomposting the optimal choice for converting organic waste into beneficial organic fertilizer while reducing reactive N loss. However, a great deal of the processes of greenhouse gases (GHG) and ammonia volatilization during vermicomposting are not well-documented. A field vermicomposting experiment was conducted by deploying earthworms (Eisenia fetida) with three types of agricultural by-products—namely, cow manure (VCM), pig manure (VPM), and biochar (VBC)—and crop (maize) residues compared with traditional composting (COM) without earthworms in the Sichuan Basin, China. Results showed that vermicomposting caused a decrease in electrical conductivity (EC) and total organic carbon (TOC) while increasing total nitrogen (TN). The greatest TN increase was found with VCM. The cumulative NH3 volatilization in COM, VCM, VPM, and VBC during experimental duration was 9.00, 8.02, 15.16, and 8.91 kg N ha−1, respectively. The cumulative CO2 emissions in COM, VCM, VPM, and VBC were 2369, 2814, 3435, and 2984 (g·C·m−2), while for CH4, they were 0.36, 0.28, 4.07, and 0.19 (g·C·m−2) and, for N2O, they were 0.12, 0.06, 0.76, and 0.04 (g·N m−2), respectively. Lower emissions of N2O, CH4, and NH3 were observed in VBC. We concluded that earthworms, as ecological engineers, enhanced reactive nutrients and reduced ammonia volatilization during vermicomposting in our test system. Overall, vermicomposting is proposed as an eco-friendly, sustainable technique that helps to reduce environmental impacts and associated health risks.

Differential Effects of Organic Amendments on Maize Biomass and Nutrient Availability in Upland Calcareous Soil

“…Compost and vermicompost were produced from the crop residues, and the experiment lasted for five months of maturation. The experimental details are reported in [33]. The earthworm species used to produce vermicompost was Eisenia fetida.…”

“…Several studies on biochar-based soil amendment have been done, particularly with compost or a mixture of other materials, to lessen the risk of using fresh biochar in soil directly [32]. Therefore, there is still a gap to study biochar-based vermicompost to compare the effects of biochar and biochar vermicompost-an amendment that is recommended as a lower emitter of gases during its preparation [33], and can be used as organic fertilizer.…”

Low-Rank Coal as a Source of Humic Substances for Soil Amendment and Fertility Management

“…Composting is a cost-effective and sustainable process of conversion of various organic wastes into compost [162]. However, composting can be related to a high loss of N through NH 3 volatilization [163]. In turn, NH 3 poses negative effects on ecosystems and indigenous biodiversity [164].…”

Impact of Biochar Application on Ammonia Volatilization from Paddy Fields under Controlled Irrigation

“…Through the background of climate change, environmental pollution, energy shortage, and agricultural sustainable development in recent years, biochar has attracted wide attention for its carbon sequestration and emission reduction, soil improvement [8], and environmental remediation [9][10][11][12][13]. Biochar is a solid product derived from the pyrolysis of bio-organic materials (also known as biomass) in an anaerobic or hypoxic environment [14].…”