Abstract

BARZAN, Renan Ribeiro; SANDOVAL CONTRERAS, Héctor Augusto  and  OSORIO GARCIA, Nicolás Arturo. Nitrogen sources and rates in the initial growth of upland rice (Oryza sativa L.). Acta Agron. [online]. 2022, vol.71, n.4, pp.405-409.  Epub Apr 12, 2024. ISSN 0120-2812.  https://doi.org/10.15446/acag.v71n4.92480.

The most used nitrogen (N) sources for rice crops are urea and ammonium sulphate, with variable efficiency due to losses that may occur in soil, which leads to the need of higher rates of these nutrients that raise the production costs. The aim of this study was to evaluate nitrogen sources and rates for upland rice crops. The experiment was carried out in a greenhouse with the rice cultivar FL 8468 grown in plastic pots filled with 4.0_kg of soil. In the treatments, nitrogen from three sources (urea, ammonium sulphate and sulfammo) was added in five rates (0, 50, 100, 150 and 200 kg N ha-1) in a completely random design in the 5 x 3 factorial scheme, with four replications. The number of tillers per pot, plant height, shoot dry mass; nitrogen content and the agronomic efficiency of the sources were evaluated. Urea and ammonium sulphate showed better results for tillering and shoot dry mass, while N rates presented a quadratic growth for the same characteristics. Higher N rates raised the plant height, even more when urea and ammonium sulphate were applied. On the other hand, sulfammo provided better results for nitrogen content, which was also higher when the N rates increased, however, the agronomic efficiency decreased with higher N rates, while ammonium sulphate showed the best agronomic efficiency.

Keywords : Agronomic efficiency; nitrogen uptake; urea; ammonium sulphate; sulfammo.

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