Biogeochemistry

, Volume 38, Issue 3, pp 303–335

Solute dynamics in soil water and groundwater in a central Amazon catchment undergoing deforestation

  • MICHAEL R. WILLIAMS
  • THOMAS R. FISHER
  • JOHN M. MELACK
Article

DOI: 10.1023/A:1005801303639

Cite this article as:
WILLIAMS, M.R., FISHER, T.R. & MELACK, J.M. Biogeochemistry (1997) 38: 303. doi:10.1023/A:1005801303639

Abstract

Hydrochemical changes caused by slash-and-burnagricultural practices in a small upland catchment inthe central Amazon were measured. Soluteconcentrations were analyzed in wet deposition,overland flow, shallow throughflow, groundwater andbank seepage in a forested plot (about 5 ha) and anadjacent plot (about 2 ha) which had been deforestedin July 1989 and planted to manioc, and in streamwater in partially deforested and forested catchments. Measurements were made from November 1988 to June1990. The effects of slash-and-burn agriculturalpractices observed in the experimental plot includedincreased overland flow, erosion, and large losses ofsolutes from the rooted zone. Concentrations ofNO3-, Na+, K+, SO42-,Cl- and Mn in throughflow of the experimentalplot were higher than those of the control plot bymore than a factor of 10. Extensive leaching occurredafter cutting and burning, but solute transfers werediminished along pathway stages of throughflow togroundwater, and particularly within the riparian zoneof the catchment. High concentrations of N and P inoverland flow indicate the importance of usingforested riparian buffers to mitigate solute inputs toreceiving waters in tropical catchments.

Amazondeforestationhydrologic pathwaygroundwaternitrogenrain forestslash-and-burn agriculturesolutestropical

Copyright information

© Kluwer Academic Publishers 1997

Authors and Affiliations

  • MICHAEL R. WILLIAMS
    • 1
  • THOMAS R. FISHER
    • 1
  • JOHN M. MELACK
    • 3
  1. 1.Horn Point LaboratoriesCenter for Estuarine and Environmental StudiesCambridgeU.S.A
  2. 2.Institute for Computational Earth System ScienceUniversity of CaliforniaSanta BarbaraU.S.A
  3. 3.Department of Ecology, Evolution and Marine Biology, and Institute for Computational Earth System ScienceThe University of California at Santa BarbaraSanta BarbaraU.S.A