My Account: Log In | Join | Renew
Search
Author
Title
Vol.
Issue
Year
1st Page

Abstract

 

This article in JEQ

  1. Vol. 36 No. 2, p. 597-606
     
    Received: Sept 14, 2006
    Published: Mar, 2007


    * Corresponding author(s): mertensja@yahoo.co.nz
 View
 Download
 Alerts
 Permissions

doi:10.2134/jeq2006.0368

Dissolved Organic Carbon Fluxes under Bare Soil

  1. Jan Mertens *a,
  2. Jan Vanderborghtab,
  3. Roy Kasteelb,
  4. Thomas Pützb,
  5. Roel Merckxa,
  6. Jan Feyena and
  7. Erik Smoldersa
  1. a Soil and Water Management, K.U. Leuven, Celestijnenlaan 200E, B-3001 Heverlee, Belgium
    b Agrosphere, ICG-IV, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany

Abstract

The flux of dissolved organic carbon (DOC) in soil facilitates transport of nutrients and contaminants in soil. There is little information on DOC fluxes and the relationship between DOC concentration and water flux in agricultural soils. The DOC fluxes and concentrations were measured during 2.5 yr using 30 automatic equilibrium tension plate lysimeters (AETPLs) at 0.4 m and 30 AETPLs at 1.20-m depth in a bare luvisol, previously used as an arable soil. Average annual DOC fluxes of the 30 AETPLS were 4.9 g C m−2 y−1 at 0.4 m and 2.4 g C m−2 y−1 at 1.2 m depth. The average leachate DOC concentrations were 17 mg C L−1 (0.4 m) and 9 mg C L−1 (1.2 m). The DOC concentrations were unrelated to soil moisture content or average temperature and rarely dropped below 9 mg C L−1 (0.4 m) and 5 mg C L−1 (1.2 m). The variability in cumulative DOC fluxes among the plates was positively related to leachate volume and not to average DOC concentrations at both depths. This suggests that water fluxes are the main determinants of spatial variability in DOC fluxes. However, the largest DOC concentrations were inversely proportional to the mean water velocity between succeeding sampling periods, suggesting that the maximal net DOC mobilization rate in the topsoil is limited. Elevated DOC concentrations, up to 90 mg C L−1, were only observed at low water velocities, reducing the risks of DOC-facilitated transport of contaminants to groundwater. The study emphasizes that water flux and velocity are important parameters for DOC fluxes and concentrations.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © 2007. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyASA, CSSA, SSSA

Facebook   Twitter