O fogo em culturas agrícolas e florestais no cerrado: efeitos na biomassa, no solo e métodos de controle

Abstract

The Cerrado, one of the most biodiverse regions in the world, faces significant challenges due to frequent fires, which impact vegetation composition, soil quality, and agricultural and forest ecosystems. These fires are often intensified by climate change and human activities, drastically altering the natural dynamics of the system. This study sought to evaluate the effects of fire on different crops (sorghum, corn, pasture, and eucalyptus) in the Cerrado region of Goiás, in addition to testing the effectiveness of flame retardants in controlling the fires. The study was conducted at the UEG/Ipameri experimental farm. Five concentrations (0%, 10%, 15%, 20%, and 30%) of the monoammonium-based fire retardant were tested. Application was carried out using a backpack pump to ensure uniform distribution of the product across the plots. The variables analyzed were: environmental variables, flame temperature, fire propagation speed, flame height, fire intensity, biomass, and soil chemical components. The results showed that eucalyptus was most strongly associated with most of the variables that influence fire, especially high biomass load and low relative humidity. When comparing the different crops without the application of retardant, pasture stood out for its faster fire propagation, while sorghum recorded lower biomass consumption and corn had higher relative humidity, which is a predictor of fuel moisture. As for soil fertility, a temporary increase was observed after the burn, followed by a decline after six months. The fire retardant demonstrated effectiveness at a 30% concentration, significantly reducing flame height, temperature, and speed. The other concentrations tested (10%, 15%, and 20%) performed worse than the 30% concentration. Vegetation structure and climatic conditions influence fire behavior, as the quantity and arrangement of fuel determine flame intensity and speed, while factors such as temperature and humidity regulate fire height and temperature. Retardant presents a promising tool for fire control, directly reducing fuel flammability through thermal insulation. However, its widespread use still faces the challenge of high costs. Therefore, management strategies that consider the type of vegetation and the use of retardants are essential to mitigate the effects of fire in the Cerrado.