Sensitivity analyses for the FOCUS leaching models

I G Dubus, C D Brown, S Beulke

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Systematic sensitivity analyses using two different approaches tone-at-a-time and Monte Carlo techniques) were carried out for all four FOCUS leaching models (PELMO, PESTLA, PRZM and MACRO). Four scenarios were used comprising two hypothetical pesticides and either a sandy soil or a more structured medium loam soil. This paper presents results for PELMO 3.00 and the preferential flow model MACRO 4.1. Predictions of percolation by the two models were only slightly affected by a few input parameters. In comparison, pesticide losses were affected by numerous parameters and extremely large sensitivities were noted. In most scenarios, pesticide losses predicted by the two models were most affected by sorption and degradation parameters. However, investigations for one scenario involving a structured clay loam with MACRO revealed that, under specific circumstances, pesticide losses can be more affected by changes in hydrological properties of the soil.

Original languageEnglish
Title of host publication1999 BRIGHTON CONFERENCE: WEEDS
EditorsG Marshal
Place of PublicationFARNHAM
Number of pages4
ISBN (Print)1-901396-53-3
Publication statusPublished - 1999

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