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Can the plant availability of element sulfur be enhanced through its combination with sewage sludge and hydrated lime?

Sulewski, G.D. and J.J. Schoenau . 1998. Can. J. Soil Sci.78:459-466


Elemental sulfur (S°) was combined with dried anaerobically digested sewage sludge (DDS) and/or hydrated lime (Ca(OH)2) to create a possible alternative to conventional S° fertilizers. These S° blends were studied in both powdered and pelletized form to discern both the role of DDS as a fertilizer binder and as a potential stimulator of heterotrophic S° oxidation. The S° blends were visually examined to obtain general conclusions regarding surface characteristics and potential plant availability. An incubation lasting 12 wk was used to examine the short-term release of sulfate from fine (mean particle diameter [MPD] = 82 pin) and coarse (MPD = 353 gm) S° blends. Sulfate supply potential and the effects of S° pelletization were studied in the growth chamber with canola as the test crop. An apparent link existed between enhanced S° oxidation rate and a modified surface environment produced by the combination of S° DDS Ca(OH)2. Soil amendment with S° blends containing DDS Ca(OH)2 or Ca(OH)2 showed initial oxidation rates superior to S° alone. Growth chamber observations revealed higher canola yield and sulfate recovery with application of S° blends containing DDS Ca(OH)2 over S° alone. Attempts at pelletizing the S° blends resulted in improved handling characteristics, but lowered product performance due to poor dispersion in soil.

Key Words

Elemental sulfur, sewage sludge, oxidation, plant availability