Interacting effects of cover crop and soil microbial community composition on nitrous oxide production in no-till soils

Abstract

Nitrous oxide (N2O) is an atmospheric constituent that contributes to climate warming and stratospheric ozone depletion. A large fraction of the anthropogenic N2O emission originates from agricultural soils suggesting therefore a strong connection between N2O accumulation in the atmosphere and agricultural land management. During the last 2-3 decades, no-till (NT) farming and integration of cover crops into crop rotation represent two major developments in agriculture, but much remains to be learned about the impact of these management approaches on N2O emission and underlying biological soil factors. This dissertation focuses on the contribution of different components of the soil microflora to N2O production, and how different types of cover crops (legume vs grass) affect the soil microbial community composition, mineral N availability, and N2O emission in plowed (PT) and NT soils. To address these questions, several laboratory and greenhouse experiments were conducted. Results of these experiments documented soil microbial community responses to cover crop addition and could inform the selection of cover crops most suitable to soils under different tillage practices.