Premium
Calibration and validation of a model of non‐interactive solute leaching in a clay‐loam arable soil
Author(s) -
VINTEN A. J. A.,
REDMAN M. H.
Publication year - 1990
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1990.tb00057.x
Subject(s) - loam , soil science , leaching (pedology) , soil texture , outflow , drainage , permeability (electromagnetism) , soil water , tracer , environmental science , mathematics , hydrology (agriculture) , mineralogy , geotechnical engineering , geology , chemistry , physics , oceanography , nuclear physics , ecology , biochemistry , membrane , biology
SUMMARY A capacity‐type approximate leaching model (Addiscott et al., 1986) with a simple treatment of soil matrix permeability was tested, using field tracer experiments with CaBr 2 , on hydrologically isolated plots. The model predictions are sensitive to the value of the soil matrix permeability factor, a, and four methods of estimating this parameter were evaluated: (1) using a calibration based on soil texture; (2) least‐squares fitting of the model to successive neutron probe measurements of the water content profile; (3) least‐squares fitting to daily drainage outflow; (4) least‐squares fitting to cumulative drainage outflow. The best independent method (method 3) led to slight (20–30%) under‐prediction of leaching losses for two of the four experiments, but in one experiment leaching was much less than predicted. As a management model the approach seems promising but more attention needs to be paid to estimation of the value and variability of the permeability parameter, a. The convective‐dispersion equation, using steady‐state assumptions and a fitted dispersion length, gave as good a prediction of cumulative leaching losses as the approximate model studied here.