This comes from the Brits. I wonder if it is affecting the US? Yes it is.
Long taken for granted as supplied by the soil and atmosphere, sulfur is slowly rising as a yield-limiting nutrient in Midwestern crops.
Ken Ihlenfeld is certainly finding this to be true. The West Bend, Wis, producer farms 2,500 acres including 400 acres of alfalfa used for his 400-head dairy operation. When his standard soil test couldn’t explain the yellowing and unevenness in his alfalfa fields he dug deeper including tissue testing for secondary macronutrients and micronutrients. “We discovered sulfur levels were really low,” he says.
And what would be causing that? The fight against acid rain. Got to make you ask. What do greens have against plants? They don’t like that other plant food, CO2, much either.