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Soil Organic Carbon Stocks of Rio Grande do Sul, Brazil
Author(s) -
Tornquist Carlos G.,
Giasson Elvio,
Mielniczuk Joao,
Cerri Carlos Eduardo Pellegrino,
Bernoux Martial
Publication year - 2009
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2008.0112
Subject(s) - geoprocessing , environmental science , soil carbon , soil survey , soil water , soil science , vegetation (pathology) , soil horizon , forestry , digital soil mapping , hydrology (agriculture) , soil classification , geography , geology , remote sensing , medicine , geotechnical engineering , pathology
Robust and accurate regional estimates of C storage in soils are currently an important research topic because of ongoing debate about human‐induced changes in the terrestrial C cycle. Widely available geoprocessing tools were applied to estimate native soil organic C (SOC) stocks of Rio Grande do Sul state in southern Brazil to a depth of 30 cm from previously sampled soil pedons under undisturbed vegetation. The study used a statewide comprehensive soil survey comprising a small‐scale soil map, a climate map, and a soil pedon database. Soil organic C stocks under native vegetation were calculated with two different approaches: the Tier 1 method of the Intergovernmental Panel on Climate Change (IPCC) and a refined method based on actual field measurements derived from soil profile data. Highest SOC stocks occurred in Neossolos Quartzarênico hidromórfico (Aquents), Organossolos Tiomórficos (Hemists), Latossolos Brunos (Udox), and Vertissolos Ebânicos (Uderts) soil classes. Before human use of soils, most C was stored in the Latossolos Vermelhos (Udox) and Neossolos Regolíticos (Orthents), which occupy a large area of Rio Grande do Sul. Generally, IPCC default reference SOC stocks compared well with SOC stocks calculated from soil pedons. The total SOC stock of Rio Grande do Sul was estimated at 1510.3 Tg C (5.8 kg C m −2 ) by the IPPC method and 1597.5 ± 363.9 Tg C (7.4 ± 1.9 kg C m −2 ) calculated from soil pedons. The SOC digital map and SOC database developed in this study provide crucial background information for state‐level contemporary assessment of C stocks and soil C sequestration programs and initiatives.