Report 263: Review and Evaluation of Pesticide Modeling Approaches in Rice Paddies

 The model evaluation is based on the latest version of the models at the time of this study (RICEWQ v1.73, PCPF v3.01, and PFAM v0.5) available at the time of study. All models, including executable files and/or source codes, were obtained from the model developers. The results of model evaluation in this study may not be appropriate for the updated model versions in the future. For example, the newly released versions of RICEWQ v1.90 (Williams et al., 2011) and PFAM v0.65 (Young, 2011a) have been improved according to the identified modeling issues in this report.  In this report, modifications on the RICEWQ source codes and recompilation of the program are for model evaluation only.  Standalone PCPF was developed based on the original version in Excel application, and integrated into an integrated modeling platform in this study. The developed codes and applications are for model evaluation only.  Two external modules, for paddy water management and multiple pesticide applications, are developed to enable the PCPF applications with available field data. The development and implementation of the two modules did not change the original simulation algorithms and numerical methods in PCPF. The improvement of PCPF is only developed for model evaluation in this study. In addition, the module of multiple applications may not be appropriate for general modeling applications of PCPF, especially with bi-phasic processes simulated.