This project will explore the biological basis of nitrous oxide (N²O) emissions following grassland cultivation, and potential mitigation options (shallow incorporation, manipulation of botanical composition, a novel use of the nitrification inhibitor DMPP). Simulating field-scale heterogeneity, functional genes of nitrification and denitrification, as well as microbial and earthworm community dynamics, will be studied to understand the regulation of N²O formation around decomposing residues. Promising strategies for N²O mitigation will be evaluated under field conditions.