Plant-soil interactions and nutrient availability determine the impact of elevated CO2 and temperature on cotton productivity

Elevated CO2 (C-E) and temperature (T-E) can not only affect crop physiology and growth but also soil nutrient availability, which could in turn influence crop response to C-E and T-E. However, such indirect impacts of C-E and T-E on crop productivity are often unexplored, potentially underestimating the impact of C-E and T-E at a system level. To explore the possible role of soil nutrient availability in mediating crop responses to C-E and T-E, we examined the effects of C-E and T-E on cotton productivity and soil nutrient availability in two soils. Early vegetative growth response was dominated by the interaction between C-E and T-E; T-E accelerated vegetative growth while C-E enhanced photosynthesis and vegetative growth at ambient temperature. When soil nitrogen availability became low during the reproductive phase, altered soil nitrogen availability at C-E and T-E and differences in soil characteristics influenced resource allocation and yield response, resulting in a doubling of cotton yield at T-E but only a marginal increase at C-E. Changes in soil nutrient availability induced by C-E and T-E during crop development can enhance or limit yield responses to C-E and T-E. Thus, soil responses should also be considered when developing adaptation strategy for climate change.