Asynchronous nitrogen supply and demand produce nonlinear plant allocation responses to warming and elevated CO ₂

Terrestrial ecosystem responses to climate change are mediated by complex plant-soil feedbacks that are poorly understood, but often driven by the balance of nutrient supply and demand. We actively increased aboveground plant-surface temperature, belowground soil temperature, and atmospheric CO2 in a brackish marsh and found nonlinear and nonadditive feedbacks in plant responses. Changes in root-to-shoot allocation by sedges were nonlinear, with...