RealAg Radio Product Spotlight: Sulfur Application With Dr. Cristie Preston

Nutrien Senior Agronomist Dr. Cristie Preston recently spoke with RealAg Radio about sulfur application—how to know if you need to apply sulfur, the best way to estimate application rates and the role Smart Nutrition™ MAP+MST® can play. Listen to the interview below or read Dr. Preston’s answers below.

How do you know if you need to apply sulfur to your fields?

A lot of times farmers realize that they need to apply sulfur whenever they start seeing deficiency symptoms. Right now, we are coming up on the time of the year when wheat is coming out of dormancy and greening up. We might start seeing sulfur deficiencies because the soil is not warmed up and we are not getting that mineralization from organic matter, so we need to consider applying sulfur with our nitrogen application when the wheat is greening up this spring.

What is the best way to estimate sulfur application rates if you are going to apply sulfur?

The biggest topic of conversation right now is along the lines of the nitrogen and sulfur interaction within a plant. Both nitrogen and sulfur are needed for protein synthesis and that is important for a farmer because we want to make sure we are maximizing yield but also maximizing protein content in a lot of these grains that might potentially be used for feed, or high protein content in general.

Crops have specific nitrogen to sulfur ratios that they need to maximize production. If we look at those rates and look at the sulfur that is being removed from either a previous crop or being able to estimate what sulfur the crop needs this year, we can narrow in on the levels of sulfur that we need to apply.

Soil testing for sulfur is not a good method for determining rates because there are several soil factors that go into sulfur availability, whether that’s organic matter content or sulfur that is mobile within the soil profile. A soil test is just a snapshot of what sulfur is available at that time—it could potentially be lost.

Are there certain crops that we should be thinking more about sulfur than others?

The major crops that we are focusing sulfur applications on are wheat, corn, soybeans and canola. These crops use a lot of sulfur compared to other crops and these are some of the crops that we focus on protein content in.

What role can Smart Nutrition™ MAP+MST® play in sulfur application?

The biggest goal for a nutrient management plan is to make sure you have adequate nutrients available to the plant whenever it is taking it up the most. Now take a corn plant, for example—half of the sulfur that plant is going to take up to maximize production is taken up after the corn plant reaches the reproductive stages (halfway through the corn plants’ life before it takes up half). We need to make sure that the sulfur is available to be taken up during that time.

How we can do that is with a product like Smart Nutrition MAP+MST. The sulfur is in the elemental form so that allows for the sulfur to have to be oxidized before it is plant available, allowing for that delayed release, or that slow release, of the sulfur to be available. This protects it against leaching in a lot of soil environments that we have and offers versatility with application timing. Whether they were able to apply the product this past fall or apply it in the early spring, you should have the adequate sulfur that you need from this product.

For more information about Smart Nutrition MAP+MST, please contact your local rep.