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Updated: May 5, 2026
Characterization and Application of Passive Samplers for Monitoring of Pesticides in Water
Published on: August 3, 2016
Modelling pesticide concentrations in Japanese paddy fields using the RICEWQ model.
Marta Colombo1, Julien Boulange2, W Martin Williams3
1Department of International Environmental and Agricultural Sciences, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo 183-8509, Japan; Department of Agricultural and Environmental Sciences - Production, Territory, Agroenergy (DISAA), University of Milan, Italy.
The Rice Water Quality (RICEWQ) model accurately simulates herbicide fate in Japanese paddy fields after calibration. Optimizing water management can significantly reduce pesticide loss from rice cultivation systems.
Area of Science:
- Environmental Science
- Agricultural Science
- Water Quality Modeling
Background:
- Pesticide monitoring and modeling are crucial for regulatory processes due to concerns about surface water contamination.
- The Rice Water Quality (RICEWQ) model is widely used in the U.S. for pesticide fate and transport prediction in paddy environments.
- The RICEWQ model's applicability in Japan and its performance under Japanese agricultural conditions require thorough evaluation.
Purpose of the Study:
- To evaluate the RICEWQ model's capability in simulating the fate and transport of mefenacet and pretilachlor in Japanese paddy water and soil.
- To assess the model's performance using field experimental data under Japanese conditions.
- To investigate the potential of improved water management strategies to minimize herbicide loss.
Main Methods:
- Leveraged field experimental data from Japan to assess the RICEWQ model's simulation accuracy.
- Evaluated the model's performance in predicting daily concentrations of two herbicides (mefenacet and pretilachlor) in paddy water and soil.
- Implemented a calibration framework to enhance simulation accuracy and analyzed the impact of water management on herbicide loss.
Main Results:
- The calibrated RICEWQ model demonstrated excellent performance (Nash-Sutcliffe efficiency ≥ 0.725) in simulating herbicide fate and transport in both paddy water and soil.
- The model consistently underestimated peak herbicide concentrations in paddy water during the initial three days post-application.
- Simulations indicated approximately 50% of applied herbicides were lost from the paddy system; improved water holding or storage could reduce this loss to below 10%.
Conclusions:
- The RICEWQ model, with minor pesticide-specific calibration and a straightforward calibration framework, is applicable and performs excellently for Japanese paddy conditions.
- Water management strategies, such as extending the water holding period or increasing storage depth, are effective in significantly reducing herbicide runoff.
- Findings support the adoption of the RICEWQ model for regulatory purposes in Japan and highlight the importance of integrated water management for environmental protection.
