Simulation of soil water regimes including pedotransfer functions and land-use related preferential flow

M.P.W. Sonneveld, M.A.H.M. Backx, J. Bouma

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24 Citations (Scopus)

Abstract

Differences in land use history among taxonomically identical soils often result in different hydraulic properties, derived from either laboratory measurements or pedotransfer functions (PTFs). Additionally, flow mechanisms in sandy soils may also change through differences in water repellency associated with land use history. The soil water regimes for three sandy soils of the same taxonomic unit and under pasture but with differences in land use history were simulated. The land use histories were old grassland (site A), recently reseeded grassland (site B) and previous maize-cultivated land (site C). Degrees of water repellency, as indicated by the Water Drop Penetration Time (WDPT) test, were found to be highest for the topsoil of sites A and B. Initial simulations, using continuous pedotransfer functions to derive the Mualem-Van Genuchten parameters, corresponded poorly with field measurements (TDR). Additional laboratory measurements did not result in a better correspondence. Taking account of preferential flow in sites A and B, using the mobile/immobile concept, improved modelling performance significantly. Model simulations for a limited time period showed that water storage in the top 50 cm was on average 59 mm higher for site C compared with site A, and 23 mm higher for site B compared with site A. Downward fluxes at 50-cm depth were especially larger for site A compared with sites B and C. (C) 2002 Elsevier Science B.V All rights reserved.
Original languageEnglish
Pages (from-to)97-110
JournalGeoderma
Volume112
DOIs
Publication statusPublished - 2003

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Keywords

  • soil water
  • hydraulic conductivity
  • water repellent soils
  • models
  • repellent sandy soil
  • unsaturated soil
  • movement

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