Artigo
Sulfur and zinc availability from co-granulated Zn-enriched elemental sulfur fertilizers
Autor
Mattiello, Edson M.
Silva, Rodrigo C. da
Degryse, Fien
Baird, Roslyn
Gupta, Vadakattu V. S. R.
McLaughlin, Michael J.
Institución
Resumen
Acidification by oxidation of elemental sulfur (ES) can solubilize ZnO, providing slow release of both sulfur (S) and zinc (Zn) in soil. For this study, a new granular fertilizer with ES and ZnO was produced and evaluated. The effect of incorporating microorganisms or a carbon source in the granule was also evaluated. Four granulated ES–Zn fertilizers with and without S-oxidizing microorganisms, a commercial ES pastille, ZnSO4, and ZnO were applied to the center of Petri dishes containing two contrasting pH soils. Soil pH, CaCl2-extractable S and Zn, and remaining ES were evaluated at 30 and 60 days in two soil sections (0–5 and 5–9 mm from the fertilizer application site). A visualization test was performed to evaluate Zn diffusion over time. A significant pH decrease was observed in the acidic soil for all ES–Zn fertilizer treatments and in the alkaline soil for the Acidithiobacillus thiooxidans-inoculated treatment only. In agreement with Zn visualization tests, extractable-Zn concentrations were higher from the point of application in the acidic (62.9 mg dm–3) compared to the alkaline soil (5.5 mg dm–3). Elemental S oxidation was greater in the acidic soil (20.9%) than slightly alkaline soil (12%). The ES–Zn granular fertilizers increased S and Zn concentrations in soil and can provide a strategically slow release of nutrients to the soil.