We will evaluate current agricultural systems in agricultural landscapes for biodiversity-based options for adaptation to increased rainfall variability due to climate change. The options of farmers to respond to rainfall variability differ between agro-ecological zones of Europe in terms of changing crop or cultivar choices, agricultural systems and soil management. A common, central element, however, is that the ways farmers can influence water infiltration and storage are closely related to how crop and residue management influence soil organic matter and, hence, carbon, nutrient and water loss or storage in soil and associated water and nutrient use efficiencies. In that sense, organic matter management is central in coping with increased variability of droughts and rainfall. We hypothesize that trait-based understanding of the influence of the vegetation and the soil biota on soil organic matter quantity and quality will allow farmers to manage ecosystem services for adaptation to climate-induced changes in drought and rainfall frequencies and intensities. We will choose (proxies of) traits of crops, plant litter (biota), rhizosphere biota and soil ecosystem engineers that enable us to evaluate the performance of different agricultural systems in space and time in terms of carbon allocation and water and nutrient use efficiencies. Depending on whether water deficit or surplus situations will become more prevalent under climate change, management of soil organic matter for higher water-holding capacity versus water infiltration will be more important. By focussing on the (diversity of) relevant traits, trait combinations and trait attributes rather than (the diversity of) species of plants and soil organisms, the acquired knowledge will be generic, and ultimately applicable to different agro-ecological conditions in Europe. A combination of factorial experiments and stakeholder interactions in selected agricultural landscapes is foreseen, with the aim to develop and test our understanding of (combinations of) traits and trait attributes of plants and soil, as they are affected by, and affect soil organic matter properties, topsoil hydrology and associated water and nutrient use efficiencies. Initial results will be interfaced with social actors to identify possible synergies and trade-offs with other ecosystem services considered important at the landscape level and, hence, which and to what extent adaptation strategies under climate change are feasible. Results will also be interpreted in terms of general applicability and local limitations in similar and different agro-ecological areas in Europe than the ones studied.