Dados do Trabalho

Título

SOIL CARBON DISTRIBUTION ACROSS DIFFERENT BIOMES IN BRAZIL

Resumo

Carbon (C) is the key to climate balance and sustainable development since it retains CO2 from the atmosphere which favors the biota, contributing to crop productivity in diverse environments. The C content is less studied in soil subsurface. Thus, this research aimed to evaluate the relationships between soil attributes and C from the surface to the subsurface in different biomes of Brazil. The study area covered the entire Brazilian territory, where we used 259,688 points sampled sites in the 6 biomes (Amazon, Caatinga, Cerrado, Atlantic Forest, Pampa and Pantanal). Our hypothesis is that the climate and vegetation present in each biome are the main factors influencing the differences in soil C content at depth. In order to verify this, we utilized the Oxisols as C contents comparisons criteria because this soil class predominates in Brazil. The results demonstrated that very clayey soils had higher C levels in the surface and subsurface layers, while sandy soils ones had higher levels in the surface layer but lower in the subsurface layer. There were also those with higher levels in the surface layer and lower levels in the subsurface. The oxisols from Amazon and Cerrado  demonstrated a peculiar depth-wise distribution of C content. In the Amazon biome, we observed a higher amount of C in the surface layers (12.9 g/Kg) compared to the Cerrado biome (11.8 g/Kg), due to the continuous deposition of organic matter. On the other hand, the subsurface layer of Cerrado biome presented higher contents (5.95 g/Kg) in comparison to the Amazon biome (3.68 g/Kg).Due to the predominance of shrubby and grassy vegetation in the Cerrado phytophysiognomy, there is a propensity for the formation of more abundant and deeper root systems than in other biomes. For the next stages, we intend to analyze the database using machine learning algorithms to identify the factors that exert the greatest influence on C content in both the surface and subsurface layers in these environments.

Palavras-chave

Soil Health; Soil Quality; Environment; Climate change; Decarbonisation.

Agradecimentos

The authors thanks to GeoCis Research Group for sampling and analyses.