Mitigação da emissão de CO2 em sistemas de preparo do solo com sucessão de culturas

Abstract

Climate change has been noticed and much discussed by researchers from different areas around the world. Emissions of greenhouse gases (GHGs) directly influence global warming, with carbon dioxide (CO2) being one of the most relevant gases in this context. The objective was to evaluate the CO2 emission in function of the soil tillage systems with succession of cultures. The field experiment was carried out in an experimental area at the Federal Institute of Espírito Santo - Campus Santa Teresa. In the study, two soil management systems were adopted: direct seeding (SD) and conventional tillage (PC). During the study, beans were cultivated, followed by corn planting, in addition to a fallow period in the area. Assessments of CO2 emission, temperature and soil water content were carried out between 9:00 and 12:00. The readings were obtained through a flow chamber. Near the emission assessment point, soil samples were collected to determine the water content using the gravimetric method and the temperature was measured with the aid of a soil thermometer. During the bean cultivation, the CO2 emission varied depending on the soil preparation over the planting days. Greater emission occurred in the PC and there was no significant correlation between the variables CO2 flow, water content in the soil and temperature. During the cultivation of corn, soil tillage influenced the variables analyzed, with SD showing higher values of soil water content, temperature and CO2 flow. The CO2 emission showed a significant positive correlation with the soil temperature. During the fallow period the CO2 emission was influenced by the days after the fallow starts, with a reduction in the emission values at 1, 12 and 25 days with an increase at 41 days and there was a significant positive correlation between the CO2 emission and the soil water content. For both preparation systems, the highest emissions were observed in the summer period. Conventional tillage showed a significant positive correlation between CO2 emission and soil temperature, while the no-tillage system showed a significant positive correlation with water content and soil temperature. The soil tillage system did not influence CO2 emission, temperature and water and soil content