Producing more food, feed and fiber with less impact on ecosystem services such as the biogeochemical cycles of carbon and nutrients is a major challenge ahead of us. Some solutions to design a sustainable intensification of agroecosystems pertain in the understanding of rhizosphere ecology and biogeochemistry, as the root-soil interface is a major hotspot of biological activities in soils. The aim of this talk is to give a brief overview of the key root-mediated biogeochemical processes that could be better promoted to achieve an ecological intensification of agroecosystems. Roots indeed release large amounts of organic compounds and can considerably alter nutrient concentrations as well as soil pH values in their environment. Such rhizosphere processes occur over short spatial and temporal scales as a result of the uptake and exudation activities of plant roots. These root-induced changes of rhizosphere biogeochemical properties thus have a considerable impact on : the fate of organic carbon, the dissolution/precipitation of soil minerals, the adsorption/desorption of ions, and hence the bioavailability of key major nutrients, either anions (e.g. phosphate) or cations (e.g. potassium). While much of the past research has been considering young plants under controlled conditions, there is a need to assess these processes under field conditions for mature plants as well, and to make better use of modelling to fully understand the complex interactions at play. This will be exemplified with results obtained on cereals and grain legumes in temperate conditions, as well as for fast growing trees in tropical conditions. We will also stress the need to get beyond the topsoil, and account for rhizosphere processes occurring at depth in the soil. In this respect, we will show some exciting results obtained at several meters depth with eucalypts, as affected by climate change in a unique experimental site in Brazil. The development of novel tools and approaches will definitely be instrumental, as shown through a few examples in this talk. Further understanding the rather unique rhizosphere biogeochemistry is thus pivotal to quantifying the driving role of higher plants in ecosystem services, especially support services such as soil formation, carbon and nutrient cycling. We will highlight the exciting perspectives for breeding crops and trees that most efficiently contribute to carbon sequestration at depth and acquire and cycle nutrients for improving the nutrient use efficiency of the agroecosystems of tomorrow.