Advanced Agrilytics

N, P and K critical at planting — but don’t forget Sulfur 

In the Race to Canopy  

Not surprisingly, growers usually measure the crop season by final yield. While we know yield is the ultimate goal, are there some early season indicators that signal a productive crop? Fortunately, yes. In the spring, a grower need look no further than crop canopy. 

Perhaps not a common observation, the timing of early season plant mass can tell us a lot about yield potential.  The quicker we can get a crop to canopy, or the V6 growth stage for corn, the more time the plants must absorb sunlight to fuel photosynthesis and the more shade we have for the soil, which helps optimize temperatures and water availability. These fundamental elements of crop production lay the foundation for production throughout a growing season.  

So, what can we do to help expedite that speed to canopy and, in the end, improve yield potential?  

We’ve seen some key factors. We’d like to share a few. In part three of our three-part blog series on early season crop considerations, we look at the importance starter fertilizer and sulfur as key ingredients to your early-season success.

At Advanced Agrilytics, we believe the race to crop canopy starts early.  

N, P and K critical at planting — but don’t forget Sulfur 

Starter fertilizer application and critical inputs like nitrogen, phosphorus and potassium are always common topics of conversation this time of year. Kent Klingbeil, a lead agronomist with Advanced Agrilytics, would also include another nutrient on that list: sulfur.  

Klingbeil considers starter fertilizers a critical addition to early season management. He groups them into two categories based on products and placement: pop-ups and 2×2. While both are applied during planting, pop-ups usually are in direct contact with the seed while 2x2s may be applied close to, but not touching, seed. The latter also can be sprayed on top of the seedbed. 

“I think it’s best to separate those types of starter fertilizers because, fundamentally, they have different influences in a corn plants’ early season growth,” Klingbeil says. 

“A starter’s job is to get that plant off to a great start in the first 30-45 days of growth. If it’s a pop-up or in-furrow, we’ll be covered for the first ten to fifteen days but will need to consider alternative options to ensure proper plant nutrition for the following 20 days. An earlier application of nitrogen, additional sulfur, ammonium sulfate, ammonium thiosulfate or an earlier side-dress application are all things to consider and speak to your agronomist about.”  

Early season growth is critical to a plant’s development and ultimate yield potential. Advanced Agrilytics has focused heavily on conducting research and providing growers the data that shows a larger plant has higher yield potential and is more consistent but requires adequate nutritional supply all the way through the growing season. In the race to V6 for a corn crop or rapid stand establishment and canopy development, Klingbeil likens this process to an assembly line. 

“A good start isn’t the guarantee of a successful crop. It’s the start of an assembly line that requires all parts of the line to be working together, each reliant on the previous step in the entire system,” Klingbeil says. “What else are we going to rely on to ensure the assembly line keeps progressing and we’re protecting the start that we’ve built?” 

The availability of sulfur is a key part of the assembly line – especially at V4 to V6 – when the crop goes into rapid growth and the need is at its highest. “Just like a fungicide application to promote increased plant health and disease mitigation, if we forget about sulfur, we decrease the efficiency of the assembly line,” says Klingbeil.  

Sulfur is often forgotten and can be difficult to manage, as it moves freely with water flow. Any sulfur that does not get used by the plant during a growing season will be lost with rainfall over winter. It needs to be in a grower’s early fertilization program to be accessible during the plant’s high-growth phase and continued throughout the crop season. Klingbeil also advises being aware of in-field environments to predict risk. 

“In areas with low organic matter, sulfur will become most critical and where you’ll see deficiencies first,” states Klingbeil. “Additionally, more saturated acres will have the highest potential for in-season sulfur loss and movement, as it relocates with water flow. These environmental considerations are fundamental to ensuring adequate access to sulfur, especially during that V6, rapid-growth phase.” 

Like all inputs this year, sulfur may be difficult to acquire, and expensive. That doesn’t mean a grower has to go without the integral nutrient. 

“Work with your local supplier to understand products you can access that might be a little more economically feasible but still with the ability to drive early season plant development and eventually yield. Your agronomist can help to determine where your best return on investment will be, and the intentional placement of those products to maximize yield.” 

The team of agronomy and data experts at Advanced Agrilytics provides an unbiased view of agronomic opportunities and challenges across their customers’ operations. Find your local Precision Agronomist today at or by emailing