EDAFOLOGIA, Vol. 10 (2), pp. 221-227, 2003
PÉRDIDAS DE CARBONO ORGÁNICO POR EROSIÓN EN ANDOSOLES FORESTALES DE LAS ISLAS CANARIAS
C.D. ARBELO, A. RODRÍGUEZ RODRÍGUEZ, J.L. MORA, J.A. GUERRA, C.M. ARMAS
Departamento de Edafología y Geología, Facultad de Biología, Universidad de La Laguna, Avda. Astrofísico Francisco Sánchez s/n 38204 La Laguna, Tenerife, I. Canarias. e-mail: anto-
roro@ull.es
The overall objective of this paper is to carry out a first assessment of soil organic carbon (SOC) loss mechanisms due to water erosion in Canary Islands andosols. The study is performed in expe- rimental erosion plots. The soils are classified as Fulvic Andosols or Ultic Fulvudands. The measured values of organic carbon (OC) eroded in sediments oscillate around 116±30 gC kg-1, implying losses of OC bonded to the solid phase of 114 gC m-2año-1. It has been observed that regardless of the aggregate size fraction eroded, the greatest enrichment ratios (ER) are produced for the non-oxidizable SOC (OSOC)(ER = 1.12-1.60). The physical protection of OSOC in the larger aggregates and the chemical sta- bilization of adsorbed SOC (ASOC) in the smaller-sized ones semm to be the main mechanisms of OC sequestration in these andosols. Moreover, the predominante in the sediments of the apparently more labi- le forms (OSOC), leads to the assumption that the eroded SOC act in a significant manner as a source of atmospheric CO2.
Key words: Andosols, soil organic carbon (SOC), adsorbed organic carbon (ASOC), eroded organic carbon, Canary Islands