Soil Carbon Stocks of the Brazilian Amazon Basin

Abstract

We determined stocks of C and N for soils under undisturbed vegetation across the Brazilian Amazon Basin based on 1162 soil profiles of the RADAMBRASIL survey and a digitized Brazilian soil survey map. Mean basin soil C density was 10.3 kg C m−2. Forty‐seven petagrams C and 4.4 Pg N were contained in the top 1 m of soil. Forty‐five percent of total basin soil C (21 Pg C) and 41% of total soil N (1.8 Pg N) were contained in the top 20 cm across a ≈ 5 000 000‐km2 area. Mean C/N ratio for the basin to a depth of 1 m was 10.7. Because these data represent sites with forest vegetation in the absence of significant disturbances, they represent a valuable baseline for evaluating the effects of land‐use changes on soil C stocks in the Amazon Basin.

Soil Carbon Stock and Particle Size Fractions in the Central Amazon Predicted from Remotely Sensed Relief, Multispectral and Radar Data

“…About 47% of this stock was in the 0-30-cm layer, with an average of 3.44 kg·m −2 . The CS obtained in this study, compared with those observed by different studies in the same region [33][34][35][36], is 14% to 28% lower at 0-30 cm, and 5% to 17% lower at 0-100 cm. The differences occur because this study is constrained to a single geologic formation in the Central Amazon, whereas the other studies are not.…”

Landscape and soil regionalization in southern Brazilian Amazon and contiguous areas: methodology and relevance for ecological studies

“…Therefore, this area involves great soil spatial variability, mainly regarding to soil texture which is highly related to ecological processes. It was not highlighted in previous ecological modeling studies, mainly those related to soil organic matter dynamics (Bernoux et al, 2002;Batjes and �ijk-dynamics (Bernoux et al, 2002;Batjes and �ijk-shoorn, 1999;Batjes, 2005;Cerri et al, 2007;Cochrane and Cochrane, 2006;Holmes et al, 2006;Moraes et al, 1995;Schaefer et al, 2008).…”

Brazil’s Amazonian forest carbon: the key to Southern Amazonia’s significance for global climate

“…In the 1970s, the RADAMBRASIL project collected soil profiles at approximately 3000 points scattered (unevenly) throughout Brazilian Amazonia (Brazil, Projeto RADAMBRASIL 1973-1983. These data have been analyzed by Moraes et al (1995), with weighting by the area of the different soil types in order to generate an estimate of the soil carbon stock in the top 1 m of soil under the original vegetation in the 5 9 10 6 km 2 Brazilian Legal Amazon region. The total is 47 PgC (PgC = petagrams of carbon = 10 15 gC = gigatons of carbon = billion Mg C), or an average of 94 Mg C ha -1 .…”

“…Various improvements are needed to obtain more reliable estimates of regional stocks of soil carbon (Sombroek et al 2000). The top 20 cm contains 21 PgC (or 42 Mg C ha -1 ), which represents 45 % of the carbon in the top meter of soil (Moraes et al 1995).…”

“…Carbon stock is the starting point for quantifying the climatic impacts of landuse change, both within the southern Amazonia subregion and in Brazilian Amazonia as a whole. Information specific to southern Amazonia is available for several key factors, such as the aboveground volume of the trees measured in the RADAMBRASIL surveys (Brazil, Projeto RADAMBRASIL 1973-1982, and soil carbon (e.g., Moraes et al 1995). For various other carbon stocks, estimates depend on data from other parts of Amazonia, such as belowground biomass, dead biomass (necromass), non-tree components, and secondary forest biomass.…”