Modelo de crescimento das culturas do milho e do feijão em condições de temperatura e CO2 atmosférico elevados

• Autor(a) principal: Renato, Natalia dos Santos
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1516
• topic: Modelagem; Fotossíntese; Temperatura; Milho; Feijão; CO2; Modeling; Photosynthesis; Temperature; Corn; Beans; CO2; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::AGROMETEOROLOGIA

Nowadays, climatic changes have become of great concern worldwide and agricultural activities certainly are certainly highly dependent on the climatic conditions. In this sense, this work was aimed to build a model to simulate the effects of climate conditions on the maize and beans yields as their photosynthetic rates, especially under high temperatures and high atmospheric CO2 concentrations. The model was built from the equations of photosynthesis proposed by Farquhar et al. and adapted by Yin and van Lar. Data from experiments conducted in Viçosa, within in 2008/2009 season was used for doing the calibration. Firstly, different equations of degree-days were used in order to predict the effect of temperature on the crops cycle times. Secondly, the effects of different temperatures and CO2 concentrations were simulated separately for maize and beans crops. For maize the following results were obtained: under different CO2 concentrations (380 and 700 ppm) photosynthetic rates were similar and maize yield grew by 5% with CO2 equal to 700 ppm. Under conditions of temperature increases (1, 2, 3 and 5 °C), photosynthetic rates increased considerably. Regarding responses of maize yield under different temperature conditions, the results were positive to an increase of 2 °C. However, when the simulation was made with higher temperatures increment (5 °C), the yield decreased up to 75%. With regard to the results observed for bean crop, distinct responses were observed. Increments on photosynthetic rates and bean yield under high CO2 concentration (700ppm) were noted. The yield gains reached up to 35%. However, regarding the temperature effects, photosynthetic rates remained constant whilst the bean yield decreased. For the study of the temperature in both crops (maize and beans), the productivity declines are related to the increment in respiration rates and with the decreases of the crops cycle times.