Tech Brief #1: Sustained Release of Sulfur

A laboratory study was conducted by Dr. Jake Mowrer of Texas A&M to monitor the release of sulfur from sulfur fertilizers over time, comparing applications of SUL4R-PLUS® fertilizer, ammonium sulfate and elemental sulfur. 

Study Details:

  • Laboratory study conducted by Texas A&M
  • Three different Texas soil types: a sand, a loam and a clay loam
  • Four replications
  • Sulfur release measured by leaching the sulfate from soil columns at different times over a 60-day period
  • Rate of sulfur applied was equivalent to 30 lbs./acre

Key Findings Compiled by Dr. Tracy Blackmer:

  • SUL4R-PLUS product had superior sustained release of sulfur over the 60-day evaluation, which matches crop uptake needs.
  • The ammonium sulfate released all of its sulfur in the first 5 days. Because the sulfate form is easily lost by leaching, the lack of sustained release would likely result in decreased amounts of sulfur remaining later in the season, when the crop needs it most.
  • The elemental sulfur did not release sulfur in adequate amounts to meet crop uptake needs during the 60-day period.
  • There is still more SUL4R-PLUS crop nutrient sulfate to be released in the soil solution after 60 days.

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