MODELLING MANAGEMENT STRATEGIES TO MITIGATE THE EFFECTS OF ALTERATIONS OF TEMPERATURE AND OF CO2 CONCENTRATION ON MAIZE

Abstract

Ongoing climate change may affect rainfed maize yield in Brazil, which can be attenuated by some crop management strategies. This work had the objective of evaluating, using computational modeling, management practices with potential to mitigate the effects of changes in temperature and CO₂ concentration on maize yield. The CSM-CERES-Maize model was applied to simulate the mitigating potential of using maize cultivars with 0.3 m, 0.5 m and 0.7 m deep root system, associated with 0 t ha^-1, 2 t ha^-1 and 4 t ha^-1 of crop residue left on the soil surface. A set of 33 years of daily weather data, along with soil profile data, were used to evaluate the approach in 10 regions of the state of Minas Gerais, Brazil. For most of the regions, the use of mulching and of a maize cultivar with deeper root system was not capable of attenuating the temperature rise. In contrast, any factor limiting root growth of maize to a depth of 0.30 m, causes significant yield drop, even for a scenario of reducing temperature by 3^oC or rising CO₂ concentration. In warmer and drier regions, the positive response of maize to the increase in CO₂ concentration was more pronounced.