The Importance of Sulfur

Jan 25, 2021

Sulfur has been a very popular topic around SFG during 2020. It is time to start treating sulfur like N, P, and K, because sulfur is one of the most important primary plant nutrients. It is essential in the growth and development of crops such as your corn and soybeans. Unfortunately sulfur deficiencies are starting to show up more and more in our tissue sampling and crop scouting.

Like any essential nutrient, sulfur has some key functions. Sulfur helps with the formation of chlorophyll and it also helps with the protein and enzyme production. Soybean root nodules also require sulfur to form and produce nitrogen effectively. Corn production in southern Iowa uses between 15-20 pounds of Sulfur every year and soybeans use 12-15 pounds per year. If a plant is sulfur deficient, you will be able to see yellowing in between the veins on the leaves and the plant itself will be unable to fully form. We generally see sulfur deficiencies early in the season on high clay sidehills first. Much of the “ugly duckling” stage of corn is attributed to sulfur deficiencies as well.

SFG provides four main products that contain sulfur. Elemental Sulfur, Cal Sul (Gypsum), Ammonium Sulfate and Supergrow. Elemental Sulfur (Sulfur 90) is a product that takes the most time to breakdown, sometimes up to three years. It works best applying in the fall with P & K and adding in every year before corn and soybeans. If you have waited until time to plant, you may need a quicker fix. Cal Sul (Gypsum) contains Calcium and Sulfur and only takes a growing season to break down. This product has a very strong initial release then will be very steady throughout the growing season. Calcium Sulfur can be applied in the spring or fall with P & K.

Another option is AMS (ammonium sulfate). AMS is our most soluble form of sulfur and is best in spring applications before planting or with urea over the top of growing crops. AMS will give you the quickest one-year visible results but does not carry over into any other years.

Another very popular product from SFG is Supergrow. Supergrow is a nitrogen and sulfur source and can provide the largest input of sulfur onto a field. 1 ton provides 80 pounds of sulfur and will provide all the sulfur your corn crop could need. As we know Supergrow is a separate trip across the field, but it pairs very well with in season nitrogen and can replace the need for Anhydrous Ammonia.

My product of choice is Cal Sul (gypsum) because it can be applied fall or spring with P & K and shows huge sulfur benefits in the first year of application. Also, the addition of Calcium to the soil helps with soil structure and promotes an overall healthy environment for corn and soybean production. In 2020 trials SFG was able to replicate greater than 10-bushel responses when adding in sulfur in corn production.

Sulfur is a nutrient that needs to be applied to every farm and is the easiest way to boost production after our N, P, and K are sufficient. SFG has the capability to apply Sulfur at any point during the growing season in 2021. Give us a call to learn about solving sulfur deficiencies on your farm.