Easy to use pesticide fate/effects models and statistical tools

Models add value to information and knowledge derived from measurements of pesticide fate. However, environmental studies and measurements are performed over relatively short time periods in locations which encompass a limited range of pesticides, soils, management, and weather conditions. Models can be used, inter alia, to: • Identify key factors determining the timing and amount of pesticide leaching and runoff. • Select appropriate experimental sites using available soil and weather data. • Refine monitoring and measurement protocols. • Modify and expand application prescriptions. • Extend the spatial and temporal range of pesticide fate predictions. • Integrate local-scale variability to provide broader-scale runoff and leaching loads for catchment and groundwater models. It is necessary to define the purpose of modeling- and the spatial and temporal scales involved-in order to select a model or suite of models which has the appropriate level of complexity. An essential part of model evaluation and assessment involves calibration using observed data and validation using independent data. A large range of models is available. The types of models and some commonly used implementations are discussed to help a user select an appropriate model or series of models.