Influence of Particle Size of Municipal Solid Waste Amendments and Presence or Absence of Eisenia fetida on Soil Greenhouse Gases Emission

We investigated in the laboratory the influence of a municipal solid waste applied to soil at two different particle sizes (<2 and <0.5 mm) and the presence or absence of the Eisenia fetida earthworm on soil carbon dioxide (CO2) and nitrous oxide (N2O) fluxes, as well as on the changes in chemical [ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3N), soluble carbon (C), and soluble carbohydrates] and biochemical (dehydrogenase activity) properties of the soil. The presence of Eisenia fetida caused an increase in the emission of both gases (CO2 and N2O) in municipal solid waste (MSW)-amended soils due to the enhanced soil microbial activity and the degradation of the exogenous organic matter. Soil gas fluxes were influenced by the particle size of the organic waste added. The lowest particle size (<0.5 mm) increased the contact surface of the organic amendment, facilitating the accessibility to the microorganisms, enhancing soil biological activity, and the mineralization of the organic matter.