Soil carbon dynamics in pastures and forests of the eastern Amazon

Conference · Tue Jun 01 04:00:00 EDT 1993 · Bulletin of the Ecological Society of America; (United States)

OSTI ID:5983972

Davidson, E A; Nepstad, D C; Trumbore, S E ^[1]

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1. Woods Hole Research Center, Woods Hole, MA (United States) Univ. of California, Irvine (United States)

There is a dearth of information on below-ground C budgets of tropical forests and the ecosystems that are replacing them. Mean flux of CO[sub 2] from the soil surface was 0.29 and 0.14 g C m[sup [minus]2] h[sup [minus]1] in primary forests and degraded pastures, respectively, near Paragominas, Brazil. Litterfall and fine root inputs were about two times greater in forests than pastures. The [sup 14]C and [sup 13]C contents of SOM and CO[sub 2] in a pasture cleared in 1975 show that much of the labile forest SOM has been lost and little new C has been added by pasture vegetation. A preliminary estimate of the cumulative net C loss from the pasture soil is 2.7 kg C m[sup [minus]2] (about 10% of the forest soil C inventory), and it is still losing about 0.09 kg C m[sup [minus]2] yr[sup [minus]1]. Most of the soil C turnover occurs near the surface, but most of the long-term C storage occurs below 1 m in these oxisols. About 10% of the soil C at depth has a mean residence time of years to decades and is input by the deep roots of trees in this seasonally droughty region. Grasses have fewer deep roots, and about 1/3 of the total C lost from pasture soil was from below 1 m depth.

• OSTI ID: 5983972
• Report Number(s): CONF-930798--
• Conference Information: Journal Name: Bulletin of the Ecological Society of America; (United States) Journal Volume: 74:2
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540210* -- Environment
Terrestrial-- Basic Studies-- (1990-)
BRAZIL
CARBON
CARBON COMPOUNDS
CARBON CYCLE
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
DEVELOPING COUNTRIES
ECOLOGICAL CONCENTRATION
ECOSYSTEMS
ELEMENTS
FORESTS
GRAMINEAE
LATIN AMERICA
LILIOPSIDA
MAGNOLIOPHYTA
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PASTURES
PLANTS
ROOTS
SOILS
SOUTH AMERICA
TERRESTRIAL ECOSYSTEMS
TREES