Modelagem de cana de açúcar para previsão de produtividade de canaviais no Brasil e na Austrália

Abstract

A model of sugarcane was constructed to predict the potential yield (without nutrition and water restrictions) to analyze the sustainability of new expanded cultivation areas to the ethanol production. The potential yield in terms of dry matter of sugarcane was adjusted to estimate the carbon dioxide absorption (CO2), AS C4 plant, in relation with air temperature and solar radiation to calculate a monthly production of dry mass (DM), during the crop cycle. The DM take in account a gross photosynthetic rate subtracting loses by maintenance respiration, senescence of leafs and tillers during the cycle. The BRCANE model is composed by equations which describe the physiological behaviour due to environment conditions averaging the thermal variables, which constants was obtained through adjusts of literature results with experimental data. The estimated DM by the model was contrasted with data which obtained during the cycle from experimental irrigated field (varieties RB72 454, NA 56-79, CB 41-76, CB 47-355, CP 51-22, Q138 and Q141), in the São Paulo State (Brazil) and in Bundaberg SES, Queensland (Australia). The results of total DM were modified in stalk tons per hectare through linear equation for each variety, with regression coefficients higher than 0,88. The model showed consistent simulations with DM during the CROP cycle, as well as in the prediction of yield.