The rhizosphere is the interface between roots and the soil where nutrient absorption for plant growth in agroecosystems is facilitated. An abundant and diverse rhizosphere biome is involved in biogeochemical processes, including bacteria, fungi and soil fauna, driving soil C, N and P dynamics. Plant carbon photosynthates allocated to the root and rhizosphere are priming microbial activities important for plant nutrition such as organic matter decomposition, P solubilization, N fixation, mycorrhizal nutrient transport and biocontrol of root pests. While substantial information is available on the role of individual groups of the rhizosphere microbiome in biogeochemical processes, less attention has been given to the interactions between different beneficial rhizosphere microorganisms. Also, interactions between soil fauna and rhizosphere microorganisms still remain relatively unexplored. In order to improve our knowledge on the role of the rhizosphere in C, N and P biogeochemical processes a more holistic and functional approach is required. In this review, state of the art information on the role of biotic interactions in the rhizosphere on C, N and P biogeochemical processes relevant for plant nutrition in agroecosystems is presented.