By: Laura Lindsey and Steve Culman, OSU Extension

Sulfur is an essential macronutrient for crop production, often ranked behind only nitrogen, phosphorus, and potassium in importance. Overall, for corn and soybean, deficiencies are fairly rare. However, deficiencies can occur and are most likely on sandy soils with low organic matter (<1.0%). Much like nitrogen, the primary form of sulfur in the soil is found in the organic fraction, and the form taken up by plants (sulfate) is highly mobile. For every 1 percent of organic matter, there is approximately 140 pounds of sulfur, most of which is unavailable. Like nitrogen, sulfur must be mineralized to become plant available. (Plants may exhibit sulfur deficiencies under cool, wet conditions when mineralization is slow.) Historically, sulfur was deposited in large quantities from rainfall primarily due to burning of fossil fuels. However, emission standards have resulted in a sharp decrease in sulfur deposition from the atmosphere. As this trend continues, coupled with higher yielding crops, sulfur fertilization may become more important in the future.

Figure 1. Sulfur deposition maps from 2000-2002 and 2015-2017 (USEPA, 2019).
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