Modeling the effects of tropospheric ozone on wheat growth and yield

Abstract

Abstract Elevated tropospheric ozone (O3) concentrations can negatively impact wheat growth by reducing photosynthesis and accelerating leaf senescence. Future global O3 concentrations are expected to increase in many regions, which will further limit global wheat production. However, few crop models consider the effects of O3 stress on wheat. We incorporated the effects of O3 stress on photosynthesis and leaf senescence into the DSSAT-NWheat crop model and reproduced an observed experiment and reported yield declines from the literature. Simulated wheat yields decreased as daily O3 concentrations increased above 25 ppb, with yield losses ranging from 0.26% to 0.95% per ppb O3 increase, depending on the cultivar O3 sensitivity. The model reproduced known wheat physiological responses from the combination of O3 stress with water deficit and elevated atmospheric CO2 concentration. Increased water deficit stress and elevated atmospheric CO2 both reduce the negative impact of O3, but yield benefits from elevated CO2 can be lost due to elevated O3 concentrations. The O3-modified NWheat model simulates the effects of O3 stress on wheat growth and yield in interaction with other growth factors and can be used for studies on climate change and O3 impacts.