Biotic and abiotic drivers of soil 13C isotope abundance in a spatially variable agro-ecosystem

Microbes can exert substantial influence on carbon cycling in soil. In particular, microbially-mediated decay processes enrich the carbon-13 isotope (13C) in soil organic matter (SOM), which in turn serves as an indicator of longer term soil storage of atmospheric carbon dioxide. Understanding how soil microbial populations, and the soil biotic and abiotic factors which affect them, relate to 13C enrichment is important in the development of soil-based strategies for mitigating climate change. We performed an intensive spatial sampling of a clay loam soil under corn (Zea mays L.) production, and used kriging and regression modelling to evaluate the spatial distribution of 13C level, fungal and bacterial communities, and abiotic soil factors.