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.