Mulching Affects Soil Properties and Greenhouse Gas Emissions Under Long-Term No-Till and Plough-Till Systems in Alfisol of Central Ohio

Agricultural activities emit greenhouse gases (GHGs) and contribute to global warming. Intensive plough tillage (PT), use of agricultural chemicals and the burning of crop residues are major farm activities emitting GHGs. Intensive PT also degrades soil properties by reducing soil organic carbon (SOC) pool. In this scenario, adoption of no-till (NT) systems offers a pragmatic option to improve soil properties and reduce GHG emission. We evaluated the impacts of tillage systems (NT and PT) and wheat residue mulch on soil properties and GHG emission. This experiment was started in 1989 on a Crosby silt loam soil at Waterman Farm, The Ohio State University, Columbus, Ohio, USA. Mulching reduced soil bulk density and improved total soil porosity. More total carbon (16.16 g kg⁻¹), SOC (8.36 mg L⁻¹) and soil microbial biomass carbon (152 µg g⁻¹) were recorded in soil under NT than PT. Mulch application also decreased soil temperature (0–5 cm) and penetration resistance (0–60 cm). Adoption of long-term NT reduced the GHG emission. Average fluxes of GHGs under NT were 1.84 g CO₂-C m⁻² day⁻¹ for carbon dioxide, 0.07 mg CH₄-C m⁻² day⁻¹ for methane and 0.73 mg N₂O-N m⁻² day⁻¹ for nitrous oxide compared with 2.05 g CO₂-C m⁻² day⁻¹, 0.74 mg CH₄-C m⁻² day⁻¹ and 1.41 mg N₂O-N m⁻² day⁻¹, respectively, for PT. Emission of nitrous oxide was substantially increased by mulch application. In conclusion, long-term NT reduced the GHG emission by improving the soil properties.