Modeling the effects of tropospheric ozone on the growth and yield of global staple crops with DSSAT v4.8.0

Elevated surface ozone (O (3) ) concentrations can negatively impact growth and development of crop production by reducing photosynthesis and accelerating leaf senescence. Under unabated climate change, future global O( 3 )concentrations are expected to increase in many regions, adding additional challenges to global agricultural production. Presently, few global process-based crop models consider the effects of O- 3 stress on crop growth. Here, we incorporated the effects of O 3 stress on photosynthesis and leaf senescence into the Decision Support System for Agrotechnology Transfer (DSSAT) crop models for maize, rice, soybean, and wheat. The advanced models reproduced the reported yield declines from observed O 3 -dose field experiments and O 3 exposure responses reported in the literature (O- 3 relative yield loss RMSE < 10 % across all calibrated models). Simulated crop yields decreased as daily O- 3 concentrations increased above 25 ppb, with average yield losses of 0.16 % to 0.82 % (maize), 0.05 % to 0.63 % (rice), 0.36 % to 0.96 % (soybean), and 0.26 % to 1.23 % (wheat) per ppb O- 3 increase, depending on the cultivar O (3) sensitivity. Increased water deficit stress and elevated CO 2 lessen the negative impact of elevated O- 3 on crop yield, but potential yield gains from CO 2 concentration increases may be counteracted by higher O- 3 concentrations in the future, a potentially important constraint to global change projections for the latest process-based crop models. The improved DSSAT models with O- 3 representation simulate the effects of O 3 stress on crop growth and yield in interaction with other growth factors and can be run in the parallel DSSAT global gridded modeling framework for future studies on O 3 impacts under climate change and air pollution scenarios across agroecosystems globally.