Dados do Trabalho

Título

EFFECTS OF FIRE ON SOIL PYROGENIC CARBON DETECTED BY VIS-NIR SPECTROSCOPY IN THE BRAZILIAN CERRADO

Resumo

Wildfires are widespread across different biomes, causing ecological, landscape and economic damage. The Brazilian Cerrado has climatic conditions that favor the occurrence of fires, whether provoked or spontaneous. In natural and provoked fires, there is generally incomplete combustion of organic material, resulting in the formation of compounds such as pyrogenic carbon. We aimed to assess the effects of fire on soil pyrogenic carbon using Vis-NIR spectroscopy modeling. We evaluated the distribution patterns of pyrogenic carbon stocks over time, considering the initial conditions of the area before the fire and after successive controlled fires. Therefore, we performed the same estimate as a function of the size of the soil fragment and the remaining carbonized material (ash) above the soil. We conducted pyrogenic carbon and acid oxidation analyzes before and after fires. The Vis-NIR spectroscopy served to predict elemental carbon using elemental analysis and carbon content data. The soil samples’ reflectance, carbon content and pyrogenic carbon data of the soil samples were processed using the Partial Least Square (PLS) algorithm. R2 was 0.47 for pre-fire carbon and 0.37 for pyrogenic carbon. The post-fire R2 was 0.23 for carbon and 0.31 for pyrogenic carbon. Thus, R2 was below expectations, which we attribute to the low number of analyzed samples, being preliminary results, and may not represent the general performance of the modeling. However, we understand that the results can optimize with the ash samples analyses following the both methods. These results can support integrated management of fire, promoting the storage of carbon in the soil in the Brazilian Cerrado, since studies have proven the relationship between predicted and measured data, with the covariates used. Such factors contribute to the decision making of those responsible for environmental protection and conservation of protected areas.  

Palavras-chave

Soil Health; Carbon stock; Proximal sensing

Instituição financiadora

The State of São Paulo Research Foundation (FAPESP) 2021/05129-8.

Agradecimentos

The authors thanks GeoCis Research Group for sampling and analyses.