Modelagem da produtividade da cana-de-açúcar para as principais regiões produtoras de Minas Gerais

• Autor(a) principal: Oliveira, Robson Alves de
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5236
• topic: Zona Agroecológica; Cana-planta; Cana-soca; Agroecological Zone; Plant crop; Ratoon crop; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::AGROMETEOROLOGIA

The sugarcane composes a sector of agriculture that has presented a fast and great expansion in the State of Minas Gerais, especially in the Triângulo Mineiro region, involving large amounts of capital, technology, people and information. However, few studies relate real agricultural yield (limited by water availability throughout the cycle) of sugarcane to the climatic factors characteristic of this state. In this context, the modeling presents as an important tool to integrate the factors that affect the yielding of sugarcane crop, which may generate input for the definition of public policies and decision-making, concerning the characterization of alternative management and minimization of environmental risks. Besides, the modeling may provide more sustainability in agricultural planning, reducing production costs and maximizing the use of natural resources without harming the environment. In this context, this study had for objective to parameterize, calibrate and validate the method the Agroecological Zone (AEZ) for estimating the yield limited by water (dry conditions) of sugarcane in order to make it applicable to the crop forecast, from meteorological data and culture. In simulations, meteorological data from the National Institute of Meteorology (INMET) and precipitation data of the network of rainfall stations from National Water Agency (ANA) were used as input parameters of model. For calibration and parameterization of the AEZ method, data from the cultivar RB835486 productivity of 15 experiments for the cycle of plant crop and 15 experiments for the first cycle ratoon crop which took place in, mills and distilleries in Minas Gerais, obtained from the Plant Science Department, Federal University of Viçosa and from the Breeding Program of Sugarcane (PMGCA-UFV) were used. For the cycle of plant crop, the ZAE method presented good fit with the data observed by PMGCA-UFV, with r2 = 0.77, RMSE = 7.1 t ha-1; MAE = 5.6 t ha-1, MBE = 1.0 t ha-1 and d index = 0.94. For the first cycle of ratoon crop it was obtained r2 = 0.89, RMSE = 8.4 t ha-1; MAE = 6.7 t ha-1, MBE = 5.9 t ha-1 d index = 0.95. As calibration and parameterization showed good results, it was attempted to validate the method AEZ, using a series of yielding data from the IBGE harvest from 1989/90 to 2007/08, for the Triângulo Mineiro region. Three periods of harvest ratoon crop (early, middle and late) were simulated by the AEZ method, using the average of the three periods as estimated yield. Through the analysis, it was verified a systematic error of the model with a tendency to overestimate the yield of approximately 37.0 t ha-1 (r2 = 0.55, RMSE = 37.3 t ha-1; MAE = 37.0 t ha -1, MBE = 37.0 t ha-1; d index = 0.19). However, estimates by the AEZ method followed the temporal behavior of the historical series of the average yield of the IBGE. Correcting the average trend of overestimated, the AEZ method presented satisfactory fit (r2= 0.55, RMSE= 4.9 t ha-1; MAE= 4.0 t ha-1, MBE = 0.0 t ha-1; d index = 0.80). Thus, this model presented an important tool for estimating the yield of sugarcane in macro scale in the State of Minas Gerais, assisting in planning the optimal expansion of activity in the region.