It’s pretty obvious farming is a profession that’s not for the faint of heart. Chasing the ever-moving target of healthy crops and high yields is a never-ending battle, especially when dealing with so many unpredictabilities. Even with what you can control, (aka a fertilizer plan that seems rock solid) striping and light green coloration can still pop up. What makes this more frustrating is when your neighbor’s field is the deep, healthy green straight out of a magazine. If you’ve covered your basic N-P-K bases, what could be the missing piece? The potential culprit could be N-P-K’s often forgotten about sidekick- sulfur.
Sulfur, a secondary macronutrient, ranks 4th in importance in terms of crop health. It is an immobile nutrient, so sulfur will not relocate its supply to other areas of the plant that are in need. Because of this, a consistent sulfur supply is essential throughout the entire growing season.
This immobilization causes sulfur deficiencies to pop up first on younger leaves of the plant. The key signs of deficiency are yellowing leaves on new growth, stunting, thin stems, and delayed maturity. Yellow striping is another telltale sign, but this can often be confused with magnesium, manganese or zinc.
You might be asking yourself why is this an issue now when I haven’t worried about sulfur in my entire career? (We know, it’s frustrating just once you find a “formula” the game is changed). Just like the prized nutrients (N-P-K), our increasing yields require more sulfur, leaving less and less behind for upcoming crops. The other culprit is the increased pollution prevention regulations. Obviously, these laws are beneficial for our environment, but the reduced amount of air pollution is negatively impacting sulfur levels in the soil. Without supplemental sulfur applications, crops are left to rely on the mineralization of organic matter to fulfill their sulfur needs.
What does this look like in terms of numbers? Our 2019 ProVantage data shows that growers who applied 5 to 20 units of sulfur compared to those who applied less than 5 units, had a 21-bushel advantage on corn-on-corn acres. That’s a potential $73.50 per acre advantage.
There are a wide variety of both dry and liquid fertilizers that are on our recommendation list depending on your specific operation’s needs:
Ammonium sulfate (21-0-0-24)
A dry product that can be broadcasted in spring or fall, as well as be used in dry starters and strip-till blends.
Ammonium thiosulfate (12-0-0-26)
Used for starters that aren’t in-furrow or sidedressed. This is commonly broadcasted with a weed and feed.
Can be blended or used in dry blends. On top of being an option for sulfur, some claim it helps loosen compacted soils.
Elemental Sulfur (0-0-0-90)
A great option for a late sulfur supply. Elemental sulfur must be broken down by soil microbes or oxidized into sulfate (SO4) before it’s available for crop use. This process
can take awhile depending on environmental conditions and physical sulfur size. Warm, moist soils with good aeration typically result in more sulfur release.
To ensure you aren’t limiting your crop’s potential, run some soil tests to identify your sulfur needs. Once you have a better idea of current sulfur levels and deficient areas, your Stutsman agronomist can help you pick the best form of S for your operation as well as get a tailored prescription built.
With God’s grace, (fingers crossed for more “normal” conditions) and a supplemental sulfur boost, perhaps you’ll have the picture perfect healthy green fields that everyone will be admiring come crop year 2020.
Still not sure about S? Chat with your Stutsman agronomist to see how it’s made a difference on other operations.