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

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