Canopy temperature and heat stress are increased by compound high air temperature and water stress and reduced by irrigation – a modeling analysis

Abstract. Crop yield is reduced by heat and water stress even more when these conditions co-occur. Yet, compound effects of air temperature availability on crop are poorly quantified. Existing models, relying at least partially empirical functions, cannot account for the feedbacks plant traits response to canopy temperature. We developed a fully mechanistic model, coupling energy balances, determine as function traits, stochastic environmental conditions, irrigation applications. While general, model was parameterized wheat. Canopy largely followed under well-watered conditions. But, soil potential negative than ?0.14 MPa, further reductions in led rapid rise – up 10 ?C warmer ?0.62 MPa. More intermittent precipitation higher temperatures longer periods potentially damaging temperatures. Irrigation applications aimed keeping crops could reduce but most cases were unable maintain it below threshold damage; benefits terms reduction decreased average increased. Hence, only partial solution adapt drier climates.