6533b821fe1ef96bd127c2ac
RESEARCH PRODUCT
Characterization of organic matter in topsoils under rain forest and pasture in the eastern Brazilian Amazon basin
Lydie-stella KoutikaJ. HassinkFrancis AndreuxTh. ChonéCarlos Clemente Cerrisubject
Total organic carbonchemistry.chemical_classificationgeographyTopsoilgeography.geographical_feature_categoryChemistryEcology[SDV]Life Sciences [q-bio]Soil ScienceSiltMicrobiologyPastureDecompositioncomplex mixturesAnimal scienceOxisol[SDE]Environmental SciencesOrganic matterAgronomy and Crop ScienceIncubationTAILLE DES PARTICULESdescription
In topsoils under forest and 7-, 12- and 17-year-old pastures, organic matter was characterized by analysing C and N distribution in particle-size fractions, the C decomposition rates of soil and particle-size fractions and by employing density-fractionation of macro-organic matter (>150 μm). The C and N associated with clay fractions increased with increasing age of pasture. The weight (%) of macro-organic matter and its heavy fractions (>1.37 g cm–3) also increased with increasing age of pasture. However, in a long-term incubation (100 days), these changes seemed to involve an increase in the C decomposition rate in the topsoil of the oldest pasture. Using the C decomposition rates of particle-size fractions, it appeared that silt and clay contributed differently to C decomposition in the whole soil. C associated with silt contributed to the C decomposition rate during the first 40 days of incubation, while C associated with clay contributed to C decomposition in the long-term incubation (after 40 days), especially when the clay fraction appeared to reach saturation point with respect to its ability to bind organic compounds and thus protect the soil from C loss.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1999-07-01 |