Abstract
Humans have dramatically disrupted the nitrogen (N) cycle by using artificial N fertilizers. Globally, soil N inputs have doubled over the last century, thereby contributing to global warming due to emissions of the potent greenhouse gas nitrous oxide (N2O). Moreover, increased occurrences of extreme weather events pose further risks for N2O emissions and yield stability. Therefore we need more resilient agroecosystems that use N efficiently under changing and more variable climatic conditions. Recently we showed that plant combinations with complementary traits related to nutrient acquisition resulted in lower N2O emissions. Building on these findings, we now aim to discover optimum trait-based plant combinations capable of mitigating N2O emissions under current climatic conditions as well as after flooding disturbances. Grasslands will be our model system because they represent more than half of all agricultural land. We will select promising plant species in a greenhouse screening for the subsequent field experiments. In the field we will determine whether the role of plant combinations on N2O emission is driven by plant-induced changes in soil microbial communities, and if such changes are related to plant functional traits. Secondly, we will explore spatial root complementarity effects on N2O production-consumption throughout the soil profile. Floods will be applied in the field in the first year and measurements will continue for recovery year(s) to investigate grassland community resilience. Our findings will be extrapolated to regional/international levels via process-based modelling. This research will point the way to develop sustainable and resilient agroecosystems needed in light of global change.
Netherlands