SULFUR FERTILIZER PRICES
According to U.S. fertilizer industry representatives, since 2024 the price of sulfur fertilizer has increased by 1000%. (Not a typo!) A recent price for calcium sulfate (gypsum) was about $500 per ton, depending on supplier and transportation costs. The high prices are in part because of the war in the Middle East but are also due to export controls and high industrial demand. About half the global seaborne sulfur trade comes through the Strait of Hormuz. Much has been written over the past few years about the growing need for supplemental sulfur since the atmospheric depositions of this essential nutrient have declined greatly. Reduced emissions are good for the environment because the high depositions of sulfur were primarily from industrial air pollution (acid rain), but for many farmers cleaner air has resulted in a new fertilizer expense.
While forage crops including alfalfa may need supplemental sulfur, the huge price increases should make dairy farmers think twice about how much sulfur fertilizer their crops really need. Dairy manure varies widely in S content, with most liquid manure ranging from 1.5 to 3 pounds per 1000 gallons. The S content of solid manure is 1 to 2 pounds per ton. Depending on yield, alfalfa needs between 10 and 30 lbs. of sulfur per acre; assuming a midpoint of 20 lbs./acre, 5000 gallons of liquid manure containing 2 lbs. S/1000 gallons will meet only 50% of the annual requirement. And only about half the sulfur in manure is available the year of application.
However, the above “back of envelope” calculation assumes too much: The S content of manure varies widely depending on ration composition, and since most standard manure analyses don’t include sulfur, farmers will have to request it and pay an additional fee. Dairy One charges $11 per sample when sulfur is added to a standard manure analysis, while Cumberland Valley Analytical Services charges about $12. Farmers should request this test at least once to get a baseline level, but a better idea is to make it part of their routine manure analysis.
Sulfur is very leachable, so a fall soil analysis at the normal sampling depth of 6-8” may not be a reliable predictor of sulfur levels by the following spring. I’m not a big fan of soil testing for sulfur (especially in the fall) since there’s not a good correlation between soil S levels and crop yield response. Visual symptoms are often the first sign of a sulfur deficiency, but by the time they’re noticed there may have been some yield loss.
By next spring the situation in the Middle East will hopefully have been resolved or at least improved. This should reduce the price of sulfur fertilizers, though we may never get back to 2024 prices. My recommendation is to delay sulfur fertilizer purchases until 2027. I wouldn’t recommend the use of sulfur fertilizer unless there’s a proven need for it (which may include tissue analysis). Work with your Certified Crops Consultant or Nutrient Management Planner on this.
— Ev Thomas
