Nitrogen Strategy #2 of 3: Manage ALL your N variables, not just the easy ones

Part #2

In our first blog post, we covered why nitrogen is a critical input and how managing it at the subfield level can yield a better return on your N investment. But when it comes to managing N, Decision Zones are just one piece of the puzzle. To get the best return on your N, other management factors need to be considered when planning at the farm and acre level.

Field Management

What N applications are performed on a field? Does the field receive any manure? If so, we can plug the manure into the N model and it will generate a significant N credit.

Seed Genetics

What’s the maturity of the hybrid and when will the crop need the most N? Research shows that many hybrids today will need more N later in the season.

Planting Date and Population

It’s a lot like the chicken/egg dilemma. What seeding rate will get the most corn, then how much N do you need to support your yield target?

“My farmers don’t want to waste N or seed,” explains Landon Spurling, a Granular Certified Services Agent (CSA) from southeast Nebraska. “The N model Decision Zones keep us realistic on what a field can raise, so I can help make my farmers as efficient as possible. It’s all about getting the most corn with the least inputs possible — whether that’s seed or nitrogen.”

Previous Crop

Will it be corn on corn, or corn on beans? Nitrogen is the most critical nutrient for corn yield, and there’s opportunity to be creative in your corn-on-corn N management practices. Make sure to consider all the N factors in crop rotation, or consult with your agronomist or CSA.

Field Fertility 

Nitrogen isn’t the only input to consider. Many farmers rely on their state university calculators for insights on grain removal rates. However, a recent Granular study revealed that actual rates are generally lower than state university calculated rates, hinting that university calculators may overcompensate for phosphorus and potassium nutrient removal and may not be the most accurate measure of what’s being removed from your soil with the crop. 

There’s also the theory of elemental relationships to consider — requiring a pretty deep dive into agronomy but proving that micronutrient balancing is as important as balancing between macronutrients. As shown in Mulder’s Chart, we know that some elements are antagonistic to each other, and some are complimentary. If you have an imbalance of one nutrient vs the other, either:

  • Applying more of the opposite nutrient may decrease the other, or at least change the ratio, or
  • A third element that is antagonistic to one but another could be increased to decrease the other.  

We know every crop requires a ratio of nutrients to realize its maximum genetic potential, and that a balanced ratio of elements is more critical than the actual concentration of individual elements.


Are we able to fertigate in-season? “Here in Nebraska, we rely heavily on irrigation,” says Spurling. “With center pivot irrigation, we can put nitrogen on later in the growing season during peak N uptake. These late season applications allow us to use the nitrogen model to make up  for any N loss we encounter earlier in the growing season.”

Application Strategy

There’s lots of debate when it comes to N application method, source and equipment, but some things are indisputable:

  1. Variable rate (VR) pays off, as proven in a 2019 study by the Minnesota Corn Research and Promotion Council. When evaluating four different management plans on similar acres (one flat-rate and three other variable rate programs), the Granular Agonomy plan was $131.82 more profitable per acre over a flat rate program based on a $3.90 cash price for corn.
  2. “Blanket” applications don’t cut it. According to Spurling, most farmers can’t afford to over-apply N anymore, and many are wary of the environmental implications. In Nebraska, nitrate levels are already high in the groundwater, and he expects Natural Resource Districts (NRDs) will soon be setting N application limits.

Plug and Play All Your N Scenarios

When it comes to setting yield targets, taking all the management variables into account and running scenarios can boost the power of your corn acres.The advantage to Granular Agronomy + Nitrogen is having the opportunity to work directly with a CSA to lay out management variables and play around with different N scenarios. “The more variables we plug into our model, the better the outcome,” Spurling adds.

Think of this as a pre-game strategy, running through multiple seasons and playing “what if” with questions such as:

  • What if I split-apply this field?
  • Will a nitrogen stabilizer be useful in the spring on my poorly drained soils?
  • What if I plant at 30k/A instead of 27k/A?

With your CSA, you can try out different management plans ahead of time to see which provides the best benefits. You can run scenarios and fine-tune before you get to the field, and avoid playing “catch-up” later. 

If you want to learn more about how you can use our N model to improve planning, call us at 888-435-4726 or schedule a demo at Stay tuned for the final segment in our N series: how to manage N all season long.

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