Why Sulfur Matters More Than Ever

Sulfur is a nutrient that hasn’t received much attention until recent years. Twenty years ago, crop yields were lower, and we received enough sulfur from air pollution to meet our cropping needs. Some scientists estimate that before sulfur was removed from fuel and other emissions, rainfall supplied nearly 12 pounds of sulfur per acre each year.

As yields increase, crops remove more sulfur, meaning today’s higher-yielding corn and soybeans require more sulfur than ever before. With virtually no sulfur now coming from rainfall, supplemental applications are necessary to maximize production. A sulfur shortage can limit yields just as severely as deficiencies in nitrogen, phosphorus, or potassium.

Because sulfur is mobile in the soil profile, it can be difficult to test accurately. Soil tests provide a general baseline but are not fully reliable. Early-season plant tissue tests are the most precise, though they leave little time for corrective applications.

Yellowing of new foliage in corn and soybeans is a classic sign of sulfur deficiency. It is often confused with nitrogen deficiency, but there’s a key difference: nitrogen deficiency causes yellowing from the bottom up, while sulfur deficiency shows up from the top down. In soybeans, new leaves turn yellow or yellow-striped, giving affected areas a distinct yellow cast across the field. Sulfur-deficient soybeans also fix nitrogen more slowly.

SFG offers several effective sulfur options, including Sulfur 90% blended with fertilizer, MicroSync Pro blended with fertilizer, and Super Grow. Talk with your local SFG agronomist to determine the sulfur needs on your farm!