Dinâmica do nitrogénio inorgânico num solo arenoso tratado com sulfato de amónio

Abstract

In the last decades, with the advance of the green revolution, much of the nitrogen (N) required crops have been supplied by mineral sources of fertilizers, quantities that normally less than 50% is used by the crops, with large amounts being lost. These losses often occur with incorrect fertilization, due to the lack of knowledge about the dynamics of inorganic nitrogen under the field conditions of production. With the aim of find possible solutions to alleviate this problem, a soil test was installed (sandy) of the FAEF experimental field in Maputo, from 13 July to 25 November 2010. The design was completely randomized blocks, with 4 treatments (0-10- 20-40 KgN.ha -1) and three repetitions, the nitrogen fertilizer sulfate mineral fertilizer was used as source of nitrogen. ammonium (210 gN.Kg -1). Soil samples were taken in two layers (0-10 and 10-20 cm) in nine dates: 7/14; 7/21; 08/04; 08/18; 9/2; 9/23; 10/14; 11/4 and 11/25 of 2010, which were subjected to determination of inorganic nitrogen using the Kjedahl method. Both treatment layers showed opposite dynamics, except for the control that remained almost constant. In the 0-10 cm layer, there was leaching of inorganic nitrogen (leaching of 72.5% for treatment two; 81.6% for treatment three and 90.8% for treatment four), with exception of treatment one, which registered a 9.7% increase in inorganic nitrogen in this layer, the opposite happened in the 10-20 cm layer, where all treatments registered a growth of inorganic nitrogen content. (TRADUÇÃO NOSSA)