Elemental sulfur recommendation for pH reduction in soils from Southern Brazil/Recomendacao de enxofre elementar para a reducao do pH de solos do sul do Brasil

• Published in: Revista brasileira de engenharia agrícola e ambiental 2022-03, Vol.26 (3), p.212
• Main Authors: Dall'Orsoletta, Daniel J, Mumbach, Gilmar L, Brignoli, Fernando M, Gatiboni, Luciano C
• Format: Article
• Language: English
• ISSN: 1415-4366
• DOI: 10.1590/1807-1929/agriambi.v26n3p212-218

HIGHLIGHTS: Elemental sulfur application is an option to decrease the pH of southern Brazilian soils. The soil oxidative potential of elemental sulfur can be estimated by its magnesium concentration, acidity, and base saturation. Decrease the soil pH by one unity required the oxidation of 25 mg of elemental sulfur by kilogram of soil. The elemental sulfur ([S.sup.0]) application may reduce soil pH, benefiting plants adapted to acid conditions and lessening problems of overliming. Nevertheless, there is no official recommendation for its application. The objective of the study was to quantify the [S.sup.0] doses required to reduce the pH of soils from Southern Brazil. The experiment was carried out in the laboratory in a factorial scheme (5 X 5), with a completely randomized design and three replicates. The treatments consisted of five soils, and five doses of [S.sup.0], corresponding to 0, 50, 100, 150, and 200% of the estimated dose need to reach pH 4.0. The applied doses of [S.sup.0] resulted in reduction of pH and base saturation (V%) and increase of potential acidity (H + Al). These effects, however, were reduced due to the low rate of oxidation of the [S.sup.0] applied (0.76-3.36%). The soil variables correlated with [S.sup.0] oxidation were [Mg.sup.2+] (0.86 ***), [Al.sup.3+] (-0.82 ***), H + Al (-0.89 ***), V% (0.68 ***) and aluminum saturation (m%) (-0.87 ***). In the evaluated soils the oxidation of 50 kg [ha.sup.-1] of [S.sup.0] was required to reduce one unit of pH in [H.sub.2]O. Key words: sulfur oxidation, sulfate, acidity, overliming A aplicacao de enxofre elementar pode reduzir o pH do solo, beneficiando as plantas adaptadas as condicoes acidas e diminuindo os problemas de supercalagem. No entanto, nao ha recomendacao oficial para sua aplicacao. O objetivo deste estudo foi quantificar doses de [S.sup.0] necessarias para a reducao do pH de solos do Sul do Brasil. O experimento foi conduzido em laboratorio em um esquema fatorial (5 X 5), com delineamento inteiramente casualizado e tres repeticoes. Os tratamentos foram constituidos por cinco solos e cinco doses de [S.sup.0], correspondente a 0, 50, 100, 150 e 200% da necessidade estimada para atingir pH 4,0. A aplicacao de [S.sup.0] resultou na reducao do pH e da saturacao por bases (V%) e no aumento da acidez potencial (H + Al) esses efeitos, contudo, foram reduzidos em funcao da baixa taxa de oxidacao do [S.sup.0] aplicado (0,76-3,36%). As variaveis de solo correlacionadas com a oxidacao de [