Belowground Carbon Stock in a Cerrado Vegetation in Brazil.

Forests play an important role in mitigating the effects of global warming. In environments such as the Brazilian cerrado stricto-sensuwhich has a high ratio root: shoot and well-defined seasonality, the belowground (BWG) carbon to 1 m depth corresponds to 80% of total C and should be considered in REDD + projects as a strategy to recover and preserve the biome. The aim of this study was to evaluate the seasonal variation of SOC, C present in the roots up to 1 meter depth and total BWG carbon.

Forty simple samples were collected for analysis of SOC as well as density cores in an irregular sampling grid to assess the content C. The data were analyzed by Tukey Test 5%. Roots were collected in 5 trenches of 0.25 m x 0.25 m x 1m and divided into the following diameter classes: <2 mm, 2-5mm, 5-10mm and > 10mm; also, the roots were dried, weighed and analyzed for C content. The total C stock was obtained from the sum of the SOC stock and roots C stock.

There were significative differences in the SOC stock layers in the dry and rainy seasons, with the stock up to a meter being approximately 2 times greater than those considered on the methodologies of BWG quantification available nowadays. The amount of thick roots exceeds the amount of fine roots at all depths. The carbon content in the soil was 3.6 times greater than the carbon in the roots.