The forthcoming climatic scenario, where elevated atmospheric carbon dioxide (CO 2) concentrations are expected, will challenge crop performance with a higher demand for nitrogen (N), which will further aggravate N losses from agrosystems that are already polluting air and water systems (Anas et al., 2020; IPCC, 2022), making it imperative to anticipate and develop novel and climate-smart agriculture. Research related to plants showing the ability to produce biological nitrification inhibitors (BNI) as a mitigation strategy is currently in vogue (Saud et al., 2022). Indeed, great progress has been made recently in the characterization of species with this ability, in the production of BNI molecules, and even in the development of new crop lines aimed at incorporating this trait. However, the implications of future environmental conditions on the BNI strategy remain overlooked and need to be addressed. In this study, we aimed to establish the connections between the predicted elevated eCO 2 conditions and the production and activity of BNI compounds in plants and soil. We hypothesize that enhanced carbon assimilation by plants could improve their BNI capacity, promoting ammonium occurrence in the soil, which would particularly benefit ammonium-adapted crop varieties

Departamento de Alimentación, Desarrollo Rural, Agricultura y Pesca del Gobierno Vasco (00048- IDA2021-45) Grupo Consolidado del Gobierno Vasco (IT1560-22) Proyecto ERA-Net Cofund SuSCrop (PCI2020-120685-2) y CDTI (00139688/IDI- 20210754) Proyecto TED2021-132279B-I00, MCIN/AEI/10.13039/501100011033, EU “NextGenerationEU”/PRTR. Beca postdoctoral del Gobierno Vasco (POS-2018-1- 005) Beca posdoctoral Margarita Salas postdoctoral Ministerio de Universidades, del Gobierno de España and Programa “NextGenerationEU”