Comparison of measured and simulated atrazine mobility in two alluvial soils

Atrazine was applied on a sandy loam, Typic Fluvaquent and a silty loam, Typic Udifluvent at a 1.4 kg ha⁻¹ a.i. rate on March 28, 1989. One month later, soil samples were taken at a 60 cm depth for measurement of the atrazine concentration. Similar concentrations were measured in the two soils. The atrazine transport was also simulated by using a physically-based model (HYDRUS). Analyses showed that HYDRUS predicted the atrazine mobility. A sensitivity analysis of the model with respect to sorption, degradation and hydraulic parameters showed that the sorption one was the most relevant in the simulation process. By calibrating the model with the best-fitted Kd value, the model predictions were appreciably improved.