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Understanding mechanisms of sulfur cycling in Minnesota soils and availability from fertilizer

Study author(s): Daniel Kaiser, University of Minnesota, Department of Soil, Water, and Climate
Years of study: Ongoing (2020 – present)
Location: Becker MN, Morris MN, Rosemount MN, and Waseca MN

Important: to view the complete findings, including all tables and figures, please download the full research reports using the links to the right.

2022 summary

  • Sulfur increased corn grain yield at two of four locations. Application of 10-20 lbs of S per acre was sufficient for medium to fine textured soils with soil organic matter concentrations of 4% or greater while 10-20 lbs of S was required for sandy soils (considering 2019 to 2022 data)
  • Sulfate forms of sulfur generated the highest grain yield at one location while finely ground elemental S co-granulated with potash fertilizer (MST product) produced yield equal to sulfate.
  • Year 4 continues to show a lack of oxidation of sulfate from Tiger 90 as indicated by PRS probe and yield and plant tissue data.
  • All forms of sulfur produced equal yield potential at a sandy irrigated location.
  • Ion probe data show that elemental S does take time to start oxidizing in Minnesota soils and may provide long-term S availability over the growing season. Finely ground elemental S was shown to be more effective in medium-fine textured soils than an elemental S- bentonite product such as Tiger 90.
  • Recovery of sulfate S following oxidation of elemental S at 25oC ranged from 27-79% across 26 Minnesota soils when incubated for 112 days.
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