Impactos das alterações climáticas sobre a área de cultivo e produtividade de milho e feijão no Nordeste do Brasil usando modelagem agrometeorológica.

Abstract

This study assesses the impacts of climate change on the agricultural zoning of climatic risk in cowpea and corn grown in northeastern Brazil (NEB), based on the Intergovernmental Panel on Climate Change (IPCC) reports. The water balance model, combined with geospatial technologies (GIS), was used to identify areas of the study area where the crops will suffer yield restrictions due to climate change. The data used were the time series in rainfall at least 20 years of daily data, crop coefficients, potential evapotranspiration and duration of the crop cycle. The scenarios analyzed were of increases in air temperature of 1.5, 3 and 5 oC. It was adopted as baseline for the Water Requirements Satisfaction Index for culture (WRSI), defined as the ratio between actual evapotranspiration and maximum evapotranspiration (ETr/ETm), the values of 0.55 and 0.50 for maize and cowpea bean, respectively. An increase of air temperature affects the availability of suitable agricultural area and particularly the cowpea bean and corn yield across NEB. Therefore, it is important that crops varieties better suited to hightemperature conditions should be planted. There are considerable differences between the three warming scenarios and normal climatic conditions in terms of projected effects of changes in temperature on the area suitable for cowpea bean and corn cultivation. Under the warming scenarios, the length of the growing period and yield should be drastically affected as a consequence of the decrease in agriculturally suitable area. The sowing date from January to March appears to be less affected by warming scenarios than sowing in November and December or April and May, probably due to the soil conditions and regularity of seasonal ITCZ patterns in most of northern NEB.