Plant Biomass and Reproduction Responses to Elevated Atmospheric CO2 and N in a Large-Scale Grassland Field Study

Abstract

Carbon dioxide (CO2) and soil nitrogen (N) are vital for plant growth, but anthropogenic emissions of CO2 and the use of N fertilizer are altering the cycling of these elements. In 2013, atmospheric carbon dioxide levels exceeded 400 parts per million (ppm) (NASA 2016), which have steadily increased from pre-industrial revolution levels of about 280 ppm (IPCC 2007). Plants that are more responsive to elevated CO2 levels will likely have greater abundance, possibly outcompete other species, and shift community structure and function (Ali et al. 2013). Our objective was to investigate growth and reproductive responses of coal C3 and C4 prairie grasses to differing CO2 concentrations and soil nitrogen levels to reveal possible mechanisms behind species dynamics in future climate scenarios.