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| Titel |
Functional test of pedotransfer functions to predict water flow and solute transport with the dual-permeability model MACRO |
| VerfasserIn |
J. Moeys, M. Larsbo, L. Bergström, C. D. Brown, Y. Coquet, N. J. Jarvis |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 7 ; Nr. 16, no. 7 (2012-07-12), S.2069-2083 |
| Datensatznummer |
250013365
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| Publikation (Nr.) |
 copernicus.org/hess-16-2069-2012.pdf |
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| Zusammenfassung |
Estimating pesticide leaching risks at the regional scale requires the
ability to completely parameterise a pesticide fate model using only survey
data, such as soil and land-use maps. Such parameterisations usually rely on
a set of lookup tables and (pedo)transfer functions, relating elementary
soil and site properties to model parameters. The aim of this paper is to
describe and test a complete set of parameter estimation algorithms
developed for the pesticide fate model MACRO, which accounts for
preferential flow in soil macropores. We used tracer monitoring data from 16
lysimeter studies, carried out in three European countries, to evaluate the
ability of MACRO and this "blind parameterisation" scheme to reproduce
measured solute leaching at the base of each lysimeter. We focused on the
prediction of early tracer breakthrough due to preferential flow, because
this is critical for pesticide leaching. We then calibrated a selected
number of parameters in order to assess to what extent the prediction of
water and solute leaching could be improved.
Our results show that water flow was generally reasonably well predicted
(median model efficiency, ME, of 0.42). Although the general pattern of
solute leaching was reproduced well by the model, the overall model
efficiency was low (median ME = −0.26) due to errors in the timing and
magnitude of some peaks. Preferential solute leaching at early pore volumes
was also systematically underestimated. Nonetheless, the ranking of soils
according to solute loads at early pore volumes was reasonably well
estimated (concordance correlation coefficient, CCC, between 0.54 and 0.72).
Moreover, we also found that ignoring macropore flow leads to a significant
deterioration in the ability of the model to reproduce the observed leaching
pattern, and especially the early breakthrough in some soils. Finally, the
calibration procedure showed that improving the estimation of solute
transport parameters is probably more important than the estimation of water
flow parameters. Overall, the results are encouraging for the use of this
modelling set-up to estimate pesticide leaching risks at the regional-scale,
especially where the objective is to identify vulnerable soils and "source"
areas of contamination. |
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