Parameterisation, evaluation and comparison of pesticide leaching models to data from a Bologna field site, Italy

Abstract

Effective prediction of pesticide fate using mathematical models requires good process descriptions in the models and good choice of parameter values by the user. This paper examines the ability of seven pesticide leaching models (LEACHP, MACRO, PELMO, PESTLA, PLM, PRZM and VARLEACH) to describe an arable field environment where sunflowers are grown in the Po Valley, northern Italy. Two pesticides were considered, aclonifen and ethoprophos. The models were evaluated in terms of their ability to reproduce field data of soil water content and pesticide residues in the soil and ground water. The evaluation was based on a combination of calibrated and uncalibrated runs. The results from the models were compared with each other to explore the differences between the models. The models varied in their ability to predict soil water content in the summer: the capacity models PRZM, PELMO and VARLEACH predicted less drying than MACRO, PESTLA, PLM and LEACHP. The models varied in their ability to simulate the persistence of the pesticides in the soil. Differences in the simulated pesticide degradation rate were observed between the models, due to variations in the simulated soil water content and soil temperature, and also differences in the equation linking degradation rate to soil water content. There were large differences among the predictions of the models for the mean leaching depth of ethoprophos. PRZM, PELMO, PESTLA and LEACHP all showed similar mean leaching depth to each other, whereas VARLEACH predicted lower ethoprophos mobility and PLM and MACRO predicted greater mobility. All the models overpredicted dispersion of ethoprophos through the soil profile, as compared to the field data. None of the models was able to simulate the field data of rapid leaching of pesticide to ground water except PLM after calibration of the percentage of macropores in the mobile pore space. More work is required in the parameterisation of macropore flow for those models that include this process.

Mitigation of agricultural nonpoint-source pesticide pollution in artificial wetland ecosystems

“…Their work conclusion was that none of these models describe water percolation and pesticide leaching to a complete degree of satisfaction. Although, over the experimentation period ([10 months), the best results on water percolation and pesticide tracer came from PESTLA and SIMULAT, Garratt et al (2003) compared the capacity of seven pesticide models to predict the propagation of aclonifen and ethoprophos in an environment of arable soil. The tested models were VARLEACH, LEACHP, PESTLA, MACRO, PRZM, PELMO, and PLM.…”

“…Besides, a detailed description of the models was provided. The interested reader is referred either to review compiled databases such as CAMASE (Bergamaschi and Putti 1999), REM (Register of Ecological Models 2006), or to review papers such as (Vink et al 1997;Vanclooster et al 2000, (FOCUS 2000Jones and Russell 2001;Dubus et al 2002;Garratt et al 2003). Vink et al (1997) studied unsaturated transport of the nematicide aldicarb and the herbicide simazine in a cracked clay soil.…”

Water and herbicide transient flow transport in field dried topsoils during controlled infiltration

“…The models also consider sorption and retarded intra-aggregate diffusion as predominant processes. Herbicide transport in wet or saturated soils appears to be largely controlled by this hierarchical partitioning of porosity and/or permeability combined with the sorption/intra-aggregate diffusion behaviour of herbicides (e. g. Larsson and Jarvis, 1999;Gottesbüren et al, 2000;Garratt et al, 2003). Moreover, when the soil aggregates are nearly saturated, very slow herbicide diffusion in soil solutions of wet aggregates (e.g.…”

Mitigation of Agricultural Nonpoint-Source Pesticide Pollution in Artificial Wetland Ecosystems – A Review

“…Besides, a detailed description of the models was provided. The interested reader is referred to review compiled databases as CAMASE (Bergamaschi et Putti, 1999), REM (REM, 2007), or to review papers such as Vink et al (1997), Vanclooster et al (2000), FOCUS (2000), Jones and Russel (2001), Dubus et al (2002) and Garratt et al (2003). Vink et al (1997) studied unsaturated transport of the nematicide aldicarb and the herbicide simazine in a cracked clay soil.…”

“…Their conclusion was that none of these models describe water percolation and pesticide leaching with a complete degree of satisfaction, although, over all the experimentation period (>10 months), the best results on water percolation and pesticide tracer came from PESTLA and SIMULAT. Garratt et al (2003) compared the capacity of seven pesticide models to predict the propagation of aclonifen and ethoprophos in an environment of arable soil. The tested models were: VARLEACH, LEACHP, PESTLA, MACRO, PRZM, PELMO and PLM.…”