We evaluated the effect of the addition of high fertilizer rates on the availability and leaching of micronutrients in volcanic soils. First, we evaluated the effect of phosphate fertilizer on the availability of boron. Second, we assessed the effect of high rates of potassium chloride on the solubilization of native zinc fractions. Third, we evaluated the effect of the concentration of the solution that flows through the soil on the parameters of the most used solute transport models (e.g., Convection-Dispersion Equation). Our results showed a slight phosphate-boric acid interaction, a significant effect of the addition of potassium chloride on the solubilization and leaching of zinc, and an important effect of the solution concentration on the values of the Convection-Dispersion-Equation model parameters.