IMPACTS OF CLIMATE CHANGE SCENARIOS IN THE BRAZILIAN SEMIARID REGION ON WATERMELON CULTIVARS

ABSTRACT The phenology and water demand of crops can be altered by climate change. The objective of this study was to evaluate the impacts of climate change (temperature and relative humidity) on the development and evapotranspiration (ETc) of watermelon cultivare (Citrullus lanatus Schrad) in irrigated plantations in the Brazilian semiarid region. The experiments were conducted at the Rafael Fernandes Experimental Farm, in the municipality of Mossoró, RN, Brazil. The first experiment was carried out from February to April 2006, evaluating the cultivar Mickylee. In the second experiment, carried out from September to November 2009, the cultivar Quetzali was used. Two climate change scenarios were evaluated based on the Intergovernmental Panel on Climate Change (IPCC) report: an optimistic one named B2 and a pessimistic one named A2. It was found that climate change may cause reductions in crop vegetative cycle of 14.1 and 26.9% for the cultivar Mickylee and 7.9 and 11.1% for the cultivar Quetzali, for the optimistic and pessimistic scenarios, respectively, compared to the current climate scenario. Future climate changes will increase the watermelon crop coefficient (Kc), for the conditions under which the present study was carried out, increasing the daily ETc the total ETc, mainly for the cultivar Mickylee. Future climate changes in air temperature and relative humidity will reach limits above those tolerated by the crop, which will lead to changes in the cultural practices and irrigation management. RESUMO A fenologia e a demanda hídrica das culturas podem ser alteradas pelas mudanças climáticas. Com isso, objetivou-se com o presente trabalho avaliar os impactos das mudanças climáticas (temperatura e umidade relativa do ar) sobre o desenvolvimento e a evapotranspiração (ETc) de cultivares de melancieira (Citrullus lanatus Schrad) em cultivo irrigado no semiárido brasileiro. Os experimentos foram conduzidos na Fazenda Experimental Rafael Fernandes, no município de Mossoró, RN, Brasil. O primeiro experimento foi realizado no período de fevereiro a abril de 2006, avaliando a cultivar “Mickylee”. No segundo experimento, realizado de setembro a novembro de 2009, utilizou-se a cultivar “Quetzali”. Foram avaliados dois cenários de mudanças climáticas baseados no relatório do Intergovernmental Panel on Climate Change (IPCC): um otimista denominado B2 e um pessimista denominado A2. Verificou-se que as mudanças climáticas poderão provocar redução no ciclo vegetati