Management History, Soil Porosity, and Litter Quality Interact in Regulating Organic Matter Stabilization and Greenhouse Gas Emission.

Complexity associated with understanding soil organic matter (SOM) stability and greenhouse gases (GHGs) emission from soil is in part due to interaction of a number of edaphic and non-edaphic factors. We sought to examine how interactions of substrate quality (through priming effect i.e. accelerated SOM turnover following addition of substrate), moisture conditions (optimum vs. low), soil pore characteristics (prevalence of large vs. small pores), and long-term management history control soil C dynamics and its GHGs production. Soils under 25 year conventional vs. cover cropping - from Long-Term Ecological Research, Kellogg Biological Station- were incubated (90 d) after addition of high quality (¹³C-soybean) and low quality (¹³C-corn) substrate. Headspace gas was regularly analyzed (day 1, 3, 7, 14, 24, 36, 48, 60, 72 and 90) to measure GHGs production and to determine the occurrence and intensity of priming effect. Additionally, we employed i) 16s rRNA pyrosequencing technique to trace dynamics of decomposer community and ii) X-ray micro tomography to visualize and measure losses of decomposing substrate, both at early stage of decomposition (days 7, 14 and 24).

Detailed findings will soon be included upon completion and analysis of results.