Quantifying and mitigating the effects of ozone pollution on crop production - Sunrise Work package 3.2

Ground-level concentrations of ozone are high in many crop growing regions of the world and increasing rapidly in developing countries. Ozone reduces productivity of sensitive crops by reducing photosynthesis and causing cell damage within leaves, following uptake through the leaf stomatal pores. Currently, little is known about effects on crops growing in African countries where ozone precursor emissions are rising rapidly. We worked with African scientists to select the most appropriate crops and cultivars, and exposed them to realistic current and potential future ozone regimes in the climate controlled UK CEH Bangor solardomes to quantify the factors influencing stomatal conductance (for model parameterisation) and the negative effects of ozone on yield. We used staple food crops such as wheat, beans and millets. We also tested management options that could reduce ozone impacts such as strategic timing of irrigation to develop an action plan for implementation at the farm scale. This work represents the first detailed assessment of dose-response on staple crops commonly grown in Sub-Saharan Africa. A method for applying the stomatal uptake based global risk assessments for wheat was extended to other staple food crops, including maize, rice and soybean and a global assessment was conducted. This analysis included a global comparison of the extent of ozone effects with those caused by other stresses (aridity, heat, nutrients and pests/diseases). We then developed our global stomatal flux-based risk assessment methodology for African farm systems, using model parameterisations from experimental data on African crops allowing more focused case studies on Sub-Saharan. Ultimately, the end beneficiaries will be the local population through greater stability and quantity of food supplies.