This work aimed to evaluate ametryn mobility in four types of soils, three from the semiarid region of the state of Rio Grande do Norte (Cambisol ; Fluvic Neosol; Latosolic Dystrophic Red-Yellow Argisol) and one from the state of Minas Gerais (Red-Yellow Latosol). Ametryn mobility was evaluated using PVC columns of 10 cm in diameter and 50 cm long. The experiment was conducted in a split-plot in a completely randomized design with four replications. The plots were composed by the columns, filled with the four types of soils and the subplots by 10 depths at intervals of 5 cm (0-5, 5-10, 10-15, 15-20, 20-25, 25-30 , 30-35, 35-40, 40-45 and 45-50 cm). Ametryn was applied on top of the columns (4 kg ha-1) and, 12 hours later, rainfall was simulated at the intensity of 60 mm. After 72 hours of simulated rain, the columns were placed in a horizontal position and opened longitudinally, divided into sections of 5.0 cm. At the center of each section, soil samples were collected for subsequent herbicide extraction and quantification through analysis by liquid chromatography (HPLC). Five seeds of cucumber (Cucumis sativus) were sown as bio-indicators of the presence of the herbicide. Ametryn mobility at the columns was influenced by the physical and chemical characteristics of the soil,(soil texture, organic matter, and pH). The Rio Grande do Norte semiarid region soils had higher ametryn mobility potential, being detected at up to 25, 20, and 15 cm depth in Latosolic Dystrophic Red- Yellow Argisol, Cambisol, and Fluvic Neosol, respectively. Ametryn mobility was restricted to 5 cm depth in the Red Yellow Latosol, with higher organic matter content and pH 4.7. The bioassay method was more efficient to confirm ametryn leaching than liquid chromatography.
organic matter; herbicide leaching; bioassay; chromatography
