Modelling pesticide residues on greasy wool: a comparison of alternative models of pesticide breakdown
B. J. Horton A C and N. J. Campbell BA Department of Primary Industries and Water, PO Box 46, Kings Meadows, Tas. 7249, Australia.
B Primary Industries Research Victoria (PIRVic), Department of Primary Industries, 475 Mickleham Road, Attwood, Vic. 3049, Australia.
C Corresponding author. Email: brian.horton@dpiw.tas.gov.au
Australian Journal of Experimental Agriculture 47(8) 918-926 https://doi.org/10.1071/EA06228
Submitted: 2 August 2006 Accepted: 6 February 2007 Published: 16 July 2007
Abstract
A comparison was made of a range of different models of wool pesticide breakdown. Linear models, with a constant rate of breakdown as the wool grows, were always inferior to models that allowed the breakdown rate to decrease as the length of wool increased. Two-pool models were usually satisfactory and only minor or no improvement was gained by inclusion of additional pools or more complex models. There was little difference in fit between models with two-way diffusion compared with one-way transfer. The ‘standard’ model, reported previously, uses two exponential functions rather than multiple pools and was usually the best fit or at least as good a fit as the two- or three-pool models. We recommend that this model continue to be used, although the two-pool model is adequate and may be easier to implement and visualise. However, the three-pool model without transfer is also satisfactory and much faster to evaluate.
Acknowledgements
The authors thank Michael Horton for helpful suggestions with the more complex aspects of the models, particularly diffusion between multiple pools. We thank Novartis Animal Health Australasia Pty Ltd for the data for cyromazine and dicyclanil.
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