Sulfur: The 4th Macronutrient


Most nutrient recommendations for soybeans traditionally focus on nitrogen, phosphorous and potassium. However, there is a fourth macronutrient that should not be neglected in nutrient plans — sulfur.

Playing a critical role in the growth and development of high-yielding soybeans, sulfur is essential for maximizing the yield potential of soybeans.

“Sulfur is a necessary nutrient for growth during the vegetative and reproductive stages of soybeans,” said Advansix Senior Agronomist Mercedes Gearhart. “It is essential for the synthesis of chlorophyll as well as sulfur-amino acids and proteins that are needed for plant growth.”

Sulfur is also required for root nodulation which provide biological nitrogen fixation, supplying about half the nitrogen used by an average soybean crop. In recent years, the crop has received less “free” nitrogen from atmospheric deposits.

In previous decades, crops received most if not all sulfur needed for average yield potential from atmospheric deposits. However, the Clean Air Act enforced stricter EPA emissions regulations that reduced atmospheric sulfur depositions across the United States, decreasing the amount of annual sulfur available to plants from the atmosphere (by over 50% in the past decade) to less than five pounds per acre. This increases the need for supplemental sulfur application across many crops, including soybeans.

In the past few decades, soybean yield potential has advanced tremendously, with modern varieties holding the potential to yield 100 bu/Acre under ideal weather conditions. Supplemental, plant-available sulfur helps unlock this yield potential. Ammonium sulfate is a proven choice for helping soybeans maximize performance.

“As a readily-available source of sulfur and nitrogen, ammonium sulfate really creates a good synergy when it comes to fertilizer,” said Gearhart. “It’s proven to really work well for enhanced plant health and yield potential in a wide range of environments and production systems.”

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