Agronomic efficiency of elemental sulphur (AE) compared with soluble and S-sulphate sulphur sources depends on reactivity of AE (e.g. particle size) and environmental conditions (soil and climate). Although there is published information suggesting that elemental sulphur has similar effectiveness than soluble sulphur sources, the information is not conclusive. We hypothesized that agronomic efficiency of AE and soluble S sources are similar under the Pampas Region conditions. The objectives of the study were to: i. Evaluate S grain response to a reactive source of AE compared to a soluble S source under different S rates and soil and climate conditions. ii. Compare, for the group of experiments, agronomic S efficiency between S sources. iii: Relate S responses with soil and climatic variables. Eight field experiments were conducted during two successive years on cropping systems in the Pampas Region. The experimental design was a randomized complete block with four or six replicates and a factorial treatment arrangement (factor 1: S source, factor 2: S rate). The treatments were: check (without S application), fertilization with a micronized source of AE (95 percent of S) and a fertilization treatment with ammonium sulphate (SA, 24 percent). Both sulphur sources were applied at two S rates. Sulphur rates were 10 and 30 kg ha-1 (year 1) and 15 and 30 kg ha-1 (year 2). In the first year, wheat responded significantly to S in four of five sites (p less than 0.05) with yield increases of 231 to 857 kg ha-1. Significant yield increases were observed in all sites in the second year, ranging from 702 to 2,119 kg ha-1. There were no significant differences in grain yield among S sources, rates or interaction source x S rates (p greater than 0.05) in most sites. When all sites were combined, sulphur sources presented similar agronomic S efficiencies (p greater than 0.05). The lower S rate (10 or 15 kg ha-1) was enough to provide S to the crop under the Pampas Region conditions. Grain yield responses to S were positively correlated with organic matter content and rainfall (during tillering or the whole crop cycle) and inversely associated with SO4 2- at planting, although with a poor adjustment. No correlation was detected between S response and temperatures during tillering or the whole crop cycle.
Torres Duggan, M., Rodriguez, M. B., Lavado, R. S., & Melgar, R. J. (2010). Eficiencia agronómica del azufre elemental relativa a una fuente azufrada soluble en trigo en la Región Pampeana. Ciencia del Suelo : Revista de la Asociación Argentina de la Ciencia del Suelo,28, (1),p.67-77
Torres Duggan, Martín, Rodríguez, Mónica Beatriz, Lavado, Raúl Silvio, Melgar, Ricardo J.. 2010. "Eficiencia agronómica del azufre elemental relativa a una fuente azufrada soluble en trigo en la Región Pampeana". Ciencia del Suelo : Revista de la Asociación Argentina de la Ciencia del Suelo 28, no.1:67-77.
Recuperado de http://ri.agro.uba.ar/greenstone3/library/collection/arti/document/2010TorresDuggan