Resumo

REUSSI CALVO, Nahuel Ignacio; ECHEVERRIA, Hernán Eduardo  e  SAINZ ROZAS, Hernán. Wheat response to sulphur fertilization in the southeast bonaerense. Cienc. suelo [online]. 2006, vol.24, n.1, pp.77-87. ISSN 1850-2067.

In the last years, a more intensive cropping in the Pampa region, and particularly in the southeast of Buenos Aires province, has caused a decrease of soil sulphur (S) availability. The objective of this work was to evaluate the effect of S fertilization on wheat (Triticum aestivum L.) grain yield, grain protein and S concentration. Another objective was to evaluate some S diagnostic methodologies reported in the literature. Two experiments were carried out in the 2003 and 2004 growing seasons at Balcarce, Argentine (37° 45' S; 58° 18'W, 130 m on sea level) on a soil with a longer agriculture history. One experiment was carried out under no-tillage (NT) and conventional tillage (CT) (Experiment A) and another experiment was carried out under NT (Experiment B). In the Experiment A treatments were tillage system (NT and CT) and nutrient combinations [T: control; nitrogen (N) + phosphorus (P); NPS]. Nutrients rates were 120 kg N ha^-1, 30 kg P ha^-1 and 15 kg S ha^-1. Tillage systems were assigned to the main plots and nutrient combination to the sub-plots. The experiment was carried out with three replications. In the Experiment B treatments were two N rates (70 and 130 kg ha^-1) and two S rates (0 and 15 kg ha^-1). The experiment was carried out with four replications. Both experiments were carried out under rainfed conditions and without P limitation. In the Experiment B and for both years, S addition increased grain yield (4.703 vs 5.328 kg ha^-1 without and with S, respectively), whereas in the Experiment A, S addition increased grain yield (4.172 vs 4.748 kg ha^-1, without and with S, respectively) only under NT in the 2004. Grain protein was not increased by S fertilization and N use efficiency was only slightly increased by S addition. Sulfur as sulfate (SO₄ =-S) concentration (0-20 cm soil depth) at sowing and grain total N/S ratio were not able to detect S deficiencies. However, the SO₄ =-S content (0-60 cm soil depth) at sowing would be a promissory methodology to detect S deficiencies.

Palavras-chave : Triticum aestivum; Sulphur; Nitrogen; Diagnostic methods.

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