Diffusion Limitation of Methane Oxidation in Soils Under Long Term No-till Management Practices.

Diffusion limitation of methane oxidation in soils under long term no-till management practices

Abstract

Long term adoption of no-till (NT) farming practices can improve the CH₄ oxidation capacity of agricultural lands through creation of a favorable soil environment for methanotrophs, increased macro-porosity and better soil gas transport. However, there is still limited data to evaluate the merit of that contention. In addition, even though the potential for biological CH₄ oxidation may exist in NT soils, restricted diffusion could limit expression of that potential in certain soil types. Therefore, both the biological and physical components of CH4 uptake must be determined. Using composite and intact cores from well-drained and poorly-drained sites, a study is being conducted to assess the CH₄ oxidation potential and gaseous diffusivity of soils under NT and conventional plowing (MP) for > 50 years. Kinetic parameters (Vmax, Km) will be derived to infer the relative affinity of methanotrophs and express their overall activity. Results of this study will help address important questions regarding cropland management practices and climate change mitigation.