Modelagem agrometeorológica para estimativa da produtividade do milho em Alagoas: presente e futuro

Abstract

Corn production is very important in the State of Alagoas, either from the food point of view or as a socioeconomic option for family farming. Thus, this research aimed to evaluate the variation of future productivity from climate change scenarios, using for this purpose an agrometeorological model calibrated for the edaphoclimatic conditions of the State of Alagoas. The first objective of the research was to determine the best sowing time for each municipality and mesoregion of Alagoas, based on the average yield obtained for each decadeof the year in the period 1980-2015, from high resolution observed data. For this, the statistical downscaling technique was used for regionalization of climate change scenarios for four reference locations in the three major mesoregions of the State, in order to study the future variation of crop yield under such scenarios, for the horizon of 2011 to 2100, divided into subperiods 2011-2040, 2041-2070 and 2071-2100.Future projections were generated for two climate scenarios from the IPCC's fifth climate change report, RCP4.5 and RCP8.5, from the average of the seven global climate models that make up the fifth report. IPCC: CANESM2 (Canada), CNRM-CM5 and IPSL-CM5A-MR (France), GFDL-ESM2M (United States), MIROC-ESM (Japan), MPI-ESM-MR (Germany), and NORESM1-M (Norway). Future climate scenarios point to higher temperatures and consequently to potential evapotranspiration, and reduced precipitation, especially from 2011-2040. Compared with IBGE's observed productivity from 1980 to 2015, the simulation of future productivity with scenario data indicates a yield reduction of around 50%, slightly more pronounced in the RCP8.5 scenario with approximately 65%.