Resumen en español

Two experiments in columns were carried out, to study how changes in organic matter and sand content of soil could affect its ability to retain added nitric nitrogen. Mixtures of A and B horizons or quartz sand and B horizon taken from soils belonging to Andisol and Oxisol orders, let us artificially change organic matter and sand content in each soil before a nitrate leaching test. Changes in sand content significantly reduce the ability to retain nitric nitrogen in both soils, and organic matter reduction accounted for a increase in nitrate leaching only in the Andisol. A brief discussion is shown, about the possible role of another conditions influencing nitrate leaching in this soils.