Simulating sulfadimidine transport in surface runoff and soil at the microplot and field scale

Area of Science:

• Environmental Science
• Soil Science
• Agricultural Science

Background:

• Environmental risk assessment for veterinary medicinal products (VMPs) is crucial to prevent water contamination.
• Physically based simulation models are used for predicting environmental concentrations, but VMP transport models require validation.
• Dual-permeability models are potential tools, but their accuracy in simulating VMP transport, especially with manure application, needs evaluation.

Purpose of the Study:

• To evaluate the MACRO model's performance in simulating sulfonamide antibiotic transport in surface runoff and soil.
• To assess the impact of liquid manure application on soil hydraulic properties and VMP transport.
• To validate the model using data from microplot and field runoff experiments on clay loam soil.

Main Methods:

• Utilized data from microplot and field runoff experiments on clay loam soil prone to preferential flow.
• Employed the dual-permeability MACRO model to simulate the transport of sulfadimidine and bromide.
• Focused on solute application via liquid manure to investigate its effects on soil hydraulic properties.

Main Results:

• The MACRO model accurately simulated sulfadimidine and bromide concentrations in microplot runoff and soil.
• Calibration using microplot data led to poor field simulation of total sulfadimidine losses, potentially due to the model's handling of surface runoff.
• Liquid manure application reduced soil hydraulic conductivity more than aqueous solutions, an effect manageable in regulatory modeling.

Conclusions:

• The MACRO model shows potential for simulating VMP transport but requires refinement for field-scale surface runoff scenarios.
• Manure application significantly impacts soil hydraulic properties, influencing VMP transport dynamics.
• Accurate environmental risk assessment for VMPs necessitates validated models that account for realistic field conditions and application methods.