How much N should I apply?
For one that’s a completely loaded question. There’s never been a “One Size Fits All” solution in farming and there never will be. Part of the reason we host meetings, webinars, etc. is to fulfill our goal to better educate you, so you have better understanding, and leading to you all to higher success. There are many factors involved in this decision and if all are considered properly, we can create a more successful plan.
The following are the main factors to consider:
1. What is my soil’s native Amino Acid Nitrogen level?
a. Why is the Amino Acid form of Nitrogen so critical?
2. What is my soil’s Ca:Mg ratio?
a. Higher soil Mg levels in most cases are not ideal. Mg% of 10-12 is ideal for most** soils. Sand being the outlier where we might want/need up to 20% Mg.
3. What does each fields Aggregate Structure look like? How would you rate it on a 1-10 scale with 10 being perfect?
a. Not every field will have the same aggregation and some won’t have any soil aggregation at all.
4. Am I adding enough Molvic and the other necessary pieces of the system to convert applied nitrogen to the Amino Acid form?
a. Once again, why is Amino Acid Nitrogen important?
5. What other antagonisms am I adding to my plan? Glyphosate, multiple fungicide apps, high rates of other fertilizers, Liberty, etc.?
6. What are recent weather/environmental conditions and what does the short term forecast look like?
a. Saturated soils change the game monumentally.
b. Dry soils will scare you.
c. Wet soils will kill you.
7. Am I adding Ca, B, ATS, Molvic and carbon sources to my applied Nitrogen to improve stability, uptake, and NUE (nitrogen use efficiency)?
8. Have I reviewed AgriBio Systems “Rules for Nitrogen” Management?
The other very important thing to consider when making decisions and/or changes. If we can answer the following 2 questions, it actually makes it easier and also greatly reduces the chance that we stub our toe or fail monumentally.
1. Does what I am considering doing and/or changing address the Root Cause?
2. If it does address the Root Cause, then does it offer one or more solutions?
In the case of Nitrogen Mgmt, here’s how a scenario might look –
I’m considering applying more Nitrogen this fall because it is cheaper than buying it in the spring.
Does the decision to apply more address the Root Cause? The Root Cause of most of our issues we face in terms of yields/profits is simply soils that do not function properly. Now don’t take this the wrong way. Most of you have never seen or experienced a functional soil.
To better understand what a functional soil can/should do here are the main six:
• Build soil/aggregate structure to allow for proper water infiltration.- Many soils are actually hydrophobic, meaning they don’t properly accept water.
• Provide all or nearly all essential nutrients for plant growth/development
• Decompose toxins
• Suppress disease causing pathogens
• Breathe/Exchange gases properly. This means breathing in O2 and releasing CO2, just as we do as humans.
Does applying more N address the Root Cause? Actually no it doesn’t. Excess Nitrogen applications are ultimately the largest cause of soil organic matter and humus decline over the last 60+ years. WHY? Every living organism must maintain its own Carbon:Nitrogen ratio. Carbon is the building block of ALL life. When bacteria feed on nitrogen, they will consume it until it’s gone. Now then, once they have gorged themselves with nitrogen, they then must balance their own C:N ratio by consuming Carbon. This carbon is mostly coming from soil organic matter and humus. If we’re not rebuilding OM/humus how do we stop the decline?
The graph above shows the uptake of nitrogen through the life cycle of a corn plant. As you can see in stage 2, V7 to VT, 50% of N uptake will occur here. This also coincides with very rapid corn plant growth. Most years corn plants will complete this stage in 3 weeks. That’s thigh high corn to tasseling in a very short time. 75% of K uptake occurs in this stage as well. This is important to know because you need to monitor your crop throughout the entire growing season. If the in-season application in dryland environments are not needed don’t spend the money. If we experience conditions that create the need for more nitrogen make sure your budget allows it. This is also why it's important to not apply all your budgeted N for the year in 1 pass. Furthermore, by over applying N at any point in time will cause you to experience a whole other problem, excessive nitrates. You have all heard me talk over the years about how important it is to control your nitrates as it can be one of our most limiting factors for growing a successful crop. Some of the common results of excessive nitrates are: disease, insect feeding, and suppressing the uptake of critical nutrients.
Dr. Mulvaney from the University of Illinois also has shown via his teams multi year study on nitrogen uptake that on average only roughly 30-35% of applied nitrogen actually makes it into plants. If you’d like more information on this please let us know. We can forward you the links to review them. So, if only roughly 30-35% of applied Nitrogen makes it into plants, where is the rest coming from? Mainly the soil. This is where soil Amino Acid nitrogen levels (AANL) are critical. Where is our baseline soil AANL? Some soils naturally today are above 150+ per acre. That’s a huge amount that will greatly improve your ability to reduce overall Nitrogen needs.
From there what are we doing to then also convert what Nitrogen we do apply to the Amino Acid form. The benefits of the Amino Acid form of Nitrogen are tremendous. We will cover those benefits next week in the next newsletter.