Background: The integration of nitrogen (N)-fixing-legumes in agrosystems can reduce N inputs. However, in a context of climate change, it is important to improve legumes resistance to drought stress in order to maintain their N fixation and productivity. At the plant level, N fixation incur a carbon (C) cost and is highly sensitive to environmental conditions. It is therefore crucial to hierarchize key traits of water and N acquisition such as root architecture, N fixation and exudation to understand what limits productivity in low input agrosystems. Objective: Root exudation of metabolites can attract beneficial microorganisms, repel pathogens and influence soil organic matter. Despite its crucial role for plant-soil interaction and nutrition, it is poorly understood. In particular, the interaction between exudation and root architecture, as well as how C and N allocation towards rhizodeposition are balanced with other functions and integrated within the C and N economy at the whole plant level remain open questions. Material and Methods: The response of pea plants to water stress (WS) and different sources of N nutrition was measured in terms of water relations, plant productivity, root structure (architecture, C:N) and function (growth, exudation, water and N uptake). Results: This study shows that WS has a bigger impact on pea traits, root structure and function than N nutrition. It decreased productivity and N uptake, induced a sinking root architecture and increased amino acids exudation. Sugar exudation was mainly affected by root position with higher exudation on mature roots. Discussion: These results provide insights on the spatial regulation of exudation, a useful step towards building a mechanistic understanding of exudation and its trade-off with productivity and WS resistance. Further, the link of these exudation patterns with microbial community structure will provide means to recruit these communities and promote plant productivity.