SUGARCANE AND CLIMATE CHANGE: EFFECTS OF CO₂ ON POTENTIAL GROWTH AND DEVELOPMENT

A model of sugarcane (Saccharum officinarum) was made to predict the potential yield under climate change scenarios to analyze the sustainability of new expanded cultivation areas in Brazil and Australia due to increased of the ethanol production. The potential yield in terms of dry matter of sugarcane was adjusted to estimate the carbon dioxide absorption (CO₂), as C4 photosynthesis plant, in relation with air temperature and solar radiation to calculate monthly production of dry mass (DM), during the crop cycle. The sugarcane DM model takes in account a gross photosynthetic rate subtracting losses by maintenance respiration, senescence of leafs and tillers during the crop cycle. The projected increase in mean temperature up to 1.3 to 2.7 °C would increase the suitability for sugarcane production. Our results indicate that the sugarcane increased its productivity under double CO₂. The simulated and observed productivity were 192 vs. 168 t/ha (sugarcane-plant) and 170 vs. 137 t/ha (ratoon). Sugarcane productivity under year 2070 scenarios will increase up to 13% both in São Paulo (Brazil) and Queensland (Australia).