A combined greenhouse climate and crop model is crucial to predict the effect of global climate change on greenhouse production. Studying the consequences of climate change on crop production needs associating several sub-models dealing with: (i) greenhouse actuators control, (ii) greenhouse climate and (iii) tomato plant growth models. We have used a combined greenhouse climate and crop model to predict hourly greenhouse climate and energy and mass fluxes and their consequences on crop production for future (2070-2099) and past (1960-1979) climate in Avignon region (South-France). The future climate corresponds to a moderate climate change scenario (+2.2 degrees C average temperature rise) and the past one to measured climate data. Comparison of preliminary results for future and past climate conditions has evidenced an average yearly air temperature rise of 1 degrees C only in the greenhouse, as against 2.2 degrees C outside. It is principally due to more elevated outside temperatures in winter, resulting in a 30% energy saving for greenhouse heating. However, considering only summer time, air temperature rise exceeds 2.2 degrees C. If we do not consider CO2 concentration rise, this temperature elevation generates negative impacts on tomato growth: both on LAI (-10%), fruit weight (-8%) and global yield (-7%), together with an increase of the plant stress duration. However, considering also the CO2 concentration elevation from 380 presently to 700 ppm in the future, one finally predicts a 20% yield increase, still with a substantial increase of the plant stress duration. This study highlights the major consequences of climate change on greenhouse production, either positive (energy saving, yield increase) or negative (greenhouse temperature rise, summer plant stress). It suggests possible adaptations of greenhouse control and management strategies, methods and new research directions for limiting the negative impacts, particularly on fruit quality.
Boulard, T (reprint author), INRA, UR880, 400 Route Chappes, F-06903 Sophia Antipolis, France.