While there has been no direct evidence of widespread sulfur deficiencies, conditions are somewhat similar to early 2009, when soils were wet and temperatures cool. If sulfur was applied and crops still look deficient, the problem may be associated with lack of uptake. No fertilizer is likely needed. An exception would be elemental sulfur applications, which require higher soil temperatures for oxidization. It is likely that very little of the elemental sulfur applied last fall would have oxidized at this time. 

Sulfur can still be applied as an early side dress, around the V5 growth stage, if a deficiency is expected. Dry fertilizer sources of sulfate sulfur can be broadcast applied at low rates. In most instances, 10 lbs. of sulfur per acre should be adequate for an in-season application. 

Some leaf burning may occur, but that generally has not been found to reduce yields. Liquid sources containing thiosulfate should not be sprayed over the top of growing corn or severe crop injury may result. Coulter injection or dribbling ammonium thiosulfate is the best method for application.


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