Impacts of regional climate change on the runoff and root water uptake in corn crops in Parana, Brazil

The natural environment of corn crops is being affected by climate changes. This research is aimed at evaluating the climate change scenarios resulting from the downscaling using the Eta regional climate model, nested in the global model CanESM2, and assessing the consequences of climate changes in the runoff and root water uptake of corn crops in the region of Parana, Brazil. This research also describes the climatology and the possible changes in the climate of the area, according to the different emission scenarios and infer how these changes will affect the dynamics of water in the corn crop in the region, simulated by Hydrus model. Simulations comprise of the historical period (1981-2005) and the future projections under RCP4.5 and RCP8.5, between the years 2046 to 2070. Eta model nested with the global model CanESM2 presented high ability to reproduce the climate in the region. Simulations showed changes in precipitation and an increasing trend of maximum and minimum temperatures when compared with the baseline. The root water uptake showed increasing trends predominantly in the RCP8.5 scenario. These climate changes can strongly affect corn production in the region of Parana, Brazil, as it can lead to increasing runoff and runoff extremes (runoff above 100 mm/day). This situation poses a risk to crop production since it causes losses by leaching and destruction of plants, as well as other factors such as lack of aeration and increased incidence of plant diseases. Similarly, the projected increase in temperature can result in increased evapotranspiration, which affects root water uptake, and the crop water demand.