Splitting Up Isn’t That Hard To Do – Multiple N Applications

December 6, 2018

Splitting Up Multiple Nitrogen Applications from Central Valley Ag on Vimeo.

This fall, some growers from my area received notice from their local NRD that they will be subject to more stringent regulations on the timing and amount of Nitrogen that they can apply to their corn fields going forward. This is by no means the first instance of regulations coming to growers about their application of crop nutrients, and I seriously doubt that it will be the last. However, as I have spoken to both Ag producers and the general public in the past couple of weeks, I think that there is some serious misunderstanding about the how and why we find ourselves dealing with regulations such as this.

Before I get into the heart of this discussion, I want to make one thing clear for all of you that may be reading this that aren’t a part of agriculture production. It is not now, nor has it ever been in the best interest of a farmer to over apply Nitrogen or any other fertilizer. Not only does it not pencil out and make budgets tighter than they need to be, but we often forget that farmers are stewards of the land. They live, work and eat within a few feet of their “offices” every day. Most farms today are part of a family operation and encompass multiple generations.

I think that there are many people outside of Agriculture that don’t understand that all plant and animal material contains nitrogen. Nitrogen was a part of this ecosystem long before we started tilling the land. Nitrogen is a part of chlorophyll, amino acids, proteins, enzymes and nucleic acids (RNA and DNA).  While there is a great amount of nitrogen in the earth's atmosphere, virtually no plants are able to use it directly.  Instead, they primarily absorb nitrates (NO3-) from the soil throughout their roots.

I could go on a scientific explanation of Nitrogen cycles and when products are in what form for all the different sources of Nitrogen. But the fact of the matter is that we are subject to loose Nitrogen up into the atmosphere from volatilization or down into the ground as Nitrates. And that is where the regulations today are starting with, the Nitrates that have worked their way down to the aquifer and into our drinking water.

The reason that government bodies like the NRD are starting with regulations about when we apply Nitrogen to our crops, and how much we can apply at a time is a result of some linear thinking. Corn takes up roughly 75% of its Nitrogen needs after the V9 stage, or in most year’s mid-June. That means if we have a 250 bu yield goal, we will take up about 170 lbs of Nitrogen after June 10th. If you look at some regulations that are out there right now that say no Nitrogen applications before March 15th, to me that can make some sense for certain soils.
Now, why do I say certain soils? There is an old rule in Agronomy that says you should put on no more than 10 pounds at a time for every 1 part Cation Exchange Capacity you have. So a CEC of 7 should not get more than 70 lbs applied at one time. This rule was built around a soils ability to safely hold onto Nitrate for a period of time.

After almost 20 years in Northern Nebraska, I decree myself as a sand farmer. I understand the challenges that come with growing a crop on a CEC of less than 12. And one of those is that split applications are a must. You just can’t put 100 lbs of N on at a time and expect all 100 lbs of it to be there for your crop. You must feed the crop throughout the year to get the yields you desire. In essence, that is what these regulations are asking us to do throughout these Nitrogen Management areas. Feed the crop when it is going to use it to eliminate the risks of losing it. And research data from multiple sources will tell us that in season applications of Nitrogen will usually lead to a yield increase.

So over the coming weeks, I am going to focus on exposing you to some tools you may not be familiar with. Tools that help us determine the right rate of Nitrogen to apply like VR Nitrogen prescriptions and Adapt-N will make up part of the discussion. New tools for application of N on our planter will be another part. And of course, we will talk about the in-season application from toolbars, sprayers, and fertigation. By necessity, this will hit a bit closer to home for some than others, but it will also be a good walkthrough for all of us on ways we may be able to improve our Nitrogen use efficiency, get more bang for our buck out of our budgets, and help the environment.

By Keith Byerly

Posted: 12/6/2018 12:24:46 PM by Kelli Reznicek | with 0 comments