global food demand while decreasing agricultural inputs such as fertilisers is required to maintain ecosystem services. Increasing the efficiency of nutrients to plants while decreasing nutrient inputs means that better exploration and exploitation of soil resources must be achieved in agroecosystems. The aim is to review the processes that govern the acquisition of soil nutrients by plants, with a particular focus on roots and rhizosphere processes and the case of major nutrients such as nitrogen and phosphorus. These rhizosphere processes are poorly accounted for in most plant nutrition models, which may largely explain why these models fail at predicting the actual uptake of poorly mobile nutrients such as phosphorus under low input conditions. A first section is dedicated to biophysical processes, while the second section concentrates on biogeochemical processes. Finally new routes for improving soil nutrient efficiency are addressed, with a particular focus on breeding and ecological engineering options. Better mimicking natural ecosystems and exploiting plant diversity appears as an appealing way forward, on this long and winding road towards ecological intensification of agroecosystems.