Movimentação de nitrato e amônio em colunas de solo

Abstract

In the conventional tillage, the annual practice of revolving the soil leads to modifications in the soil physical properties as decrease of the porosity, modification of aggregate stability and destroction of the channels left by the root system. In the no-till system, there is no revolving of the soil. Therefore, liming as well as nitrogen fertilization applied must be made on the surface due to impossibility of this application in depth. The objective of this work was to study the movement of NO-and NH+ in undisturbed soil columns, with and without liming application. The present study was carried out in the greenhouse using PVC tubes of 0.2 m of diameter and 0.2 m of length using a very clayey typical dystroferric Red Latosol, located in the UFLA campus. The undisturbed soil samples were taken in the A horizon (0-0.2 m). The irrigation and the analyses of the leached water were made daily. In the leached water, it were measured NO- and NH+ . The NO- analysis were done by two different methods. The first one is based on the NO- reduction to NO- in a Cd-Cu column. The second method used a selective electrode. The NH+ were done by the Nessler method. The experimental design was the complete randomized, with three replications. Even with usual doses of N (200 kg ha-1) amendments in a very clayey Latosols, with moderate to high Fe and Al oxide content, NO- leaching was observed.