In managing greenhouse gas emissions from agroecosystems within a changing global environment, a thorough trade-off analysis is necessary because carbon versus nitrogen management do not always go hand in hand. Furthermore, to conduct an accurate trade-off analysis, controlling factors and processes of carbon and nitrogen need to be understood and considered across a range of temporal and spatial scales.
Results/Conclusions
At the microscale, preferential C stabilization has been observed in specific soil microenvironments, but these microenvironments might also be an ideal site for N2O production, at least in the short-term. At the field scale, greater N2O fluxes concomitantly with greater soil C stabilization have been found, especially in transitional ecosystems. Furthermore, N additions are not only necessary for optimal plant growth, but they are often necessary to maintain increased C input that can be stabilized as soil C. Consequently, combining organic amendments with fertilizer additions might be warranted to ensure a sustainable management of agroecosystem services. Nevertheless, when using organic amendments, it is important to balance the short- versus long-term benefits of different qualities of organic materials, i.e. residue quality strongly affects short-term dynamics of C and N, but not long-term stabilization of soil organic C. Lastly, there is a limit on how much soil organic C can be stabilized in the soil, i.e. soil C saturation. The closer a soil is to its C saturation level, the smaller the potential for the stabilization of additional C input as soil organic C. Furthermore, a soil close to its saturation level contains a very stable soil organic C pool but a labile soil organic C pool with a relative faster turnover. It is concluded that a trade-off analysis is necessary, but complex, when managing the C and N cycles for optimal provision of agroecosystem services.
