Reports of sulfur (S) applications increasing crop yields have been described throughout the upper Midwest. Decreased atmospheric deposition of S, increased purity and usage of concentrated fertilizers, less incidental S in pesticides, and increased usage of minimal tillage systems that delay soil warming and allow accumulating crop residues to tie up plant available sulfur have all resulted in a decreased soil supply of sulfur to crops. Sulfur is a component of the amino acids cysteine and methionine both of which are used for protein production. When these amino acids are deficient, protein production and photosynthesis become severely limited impacting protein concentrations. Other studies...