Farmers are under a lot of pressure to manage their fertilizer better. From record high fertilizer prices in 2022 to growing public concern around nutrient runoff, you have to ensure you’re getting the most out of every nutrient applied to your farm. That means focusing on your nutrient use efficiency (NUE).
In simplest terms, NUE is the unit of a nutrient applied vs. unit of nutrient removed. It’s similar to how a car’s fuel efficiency is measured in miles per gallon. How much crop are you getting out of the fertilizer you applied?
Knowing your NUE, and making a plan to improve it, can help protect the future of your farm while improving your profitability.
Why Should I Care About Nutrient Use Efficiency?
The reality is, I think there’s going to be a day where people ask growers to show their work. Just like how you had to show your work in math class to get full credit, farmers will need to prove they’re being efficient with their fertilizer. It’s one thing to say your fertilizer management has improved over time; it’s another thing to show it. NUE is how you document that.
Part of the reason farmers will need to know their NUE is because of the statements the general public hears about fertilizer use. Statements like, “more nitrogen is being purchased in the U.S. today than at any other time in history.”
That is true. But the rate at which we’ve grown nitrogen purchases is nowhere near the same rate we’ve grown yield increases. We’ve increased our nitrogen use, but we’ve doubled our nitrogen efficiency. NUE gives context to those kinds of statements.
Improving Nutrient Use Efficiency Pays Off
Another reason to care about NUE is that even small improvements to it can have a big impact on your farm’s finances.
For example, let’s say you have 1,200 acres of corn and you improve your nitrogen efficiency by just 2%. That means you increase your yield by 2% without additional nitrogen. The USDA estimated that in 2021
the average corn yield was 177 bushels per acre, so that’s approximately an extra 3.5 bushels in yield. If corn is $4 per bushel, that’s an extra $14 per acre of output.
But you also need to consider that you were able to grow more corn bushels without increasing your nitrogen investment. If nitrogen is $1 per pound and it takes a pound of nitrogen to grow a bushel of corn, that means you saved yourself $3.5 worth of nitrogen.
So the total financial benefit of improving your nitrogen efficiency by just 2% is $17.50 per acre. Across 1,200 acres, that’s a $21,000 benefit. And when nitrogen is more expensive or corn prices are higher, that benefit is even greater. The math confirms that NUE is always a good investment.
Measure and Manage Nutrient Use Efficiency
So how do you measure your NUE?
There are several calculations you can run to determine NUE, but the simplest measurement is to take your most recent crop harvest and calculate how much of a nutrient you applied vs. the amount of grain you removed. So if you applied 200 pounds of nitrogen per acre and your corn yielded 175 bushels, your nitrogen efficiency is 87.5%.
But that gives you a post-mortem review. The best thing you can do to manage your nutrient use efficiencies as a whole, is to start with the way you soil sample.
Ideally, you want to soil sample from the smallest unit of farm ground that you can manage from a nutrient basis. So for instance, soil sampling from a 5-acre zone instead of 50 acres. The higher the resolution you can get in your soil sampling program, the better.
From there, we can make an accurate assessment of what our yield goals should be. And then use in-season tools like crop modeling and tissue sampling to evaluate how we’re doing.
The goal is to implement a feedback loop, so we’re constantly assessing and evaluating our nutrient use efficiency.
Start with the Agronomic Basics
Now that you’ve devised a way to collect data on your nutrient use and evaluate it, you can start making appropriate goals to improve it. I recommend trying to get just 5% better every year.
There are two ways to improve NUE. Either reduce your input and hope your output stays the same. Or keep your inputs the same and find ways to increase your output.
The truth is there is no one factor that will improve NUE. Instead, every decision we make in the cropping year impacts it — herbicides, tillage, irrigation, fungicides, planting dates, population — the list goes on. All of these impact nutrient management long before we apply nutrients.
That may seem overwhelming, but it doesn’t have to be. Just focus on making the best agronomic decision for every situation on your farm.
Let’s take corn hybrids for example. You want to select the hybrid that is well-fit for your geography, meaning you don’t necessarily want the plot winners because they probably won’t perform on every acre. But the hybrids that are consistently in the top five for your geography likely will.
So then you talk to your seed agronomist and you ask, how do they perform under different nitrogen situations? Do they perform differently if you make a fungicide application? Because these things all feed into how we make nutrient decisions. So start by making the best agronomic decisions.
Fine-Tune Your Fertilizer Plan
Now you’re ready to develop your fertilizer plan and work on your NUE. I recommend picking one nutrient at a time to try to improve, which for most growers will be nitrogen. It’s environmentally the most dynamic nutrient and often the third largest investment a grower makes, so it’s the one we can usually find the fastest economic payoff with.
Now we start to look at how we can manage that nutrient for better efficiency. With nitrogen, it could be adding a nitrogen stabilizer or changing the application timing.
Consider implementing a change based on the 4Rs fertilizer framework: applying the right nutrient source at the right rate, at the right time, and in the right place. According to Tom Bruulsema of the International Plant Nutrition Institute (IPNI),
growers can increase NUE significantly by synchronizing nutrient availability with crop demand, which could be achieved with split applications, slow and controlled-release fertilizers, stabilizers and inhibitors.
The important thing is to pick one practice, product, or technology, and test it. Once you’ve mastered that, try the next thing. And keep going. We can’t look at this as a year to year thing. We have to look at this in a decade-long timeframe.
Overcoming Capacity Constraints
The challenge most growers are going to run into in improving their NUE is capacity constraints. You may not have the equipment, labor, or time to make certain changes or improvements.
That’s where Verdesian Life Sciences can help. Our products are focused squarely on NUE and are designed to meet certain goals:
Inoculants — Improve a plant’s ability to create its own nutrients and better leverage that symbiotic relationship with bacteria in the soil
Nitrogen stabilizers, phosphorus enhancers, micronutrient lines — Enhance the efficiency of the nutrients we apply to ensure we’re delivering those on target to the plant on a higher percentage basis
Biostimulants — Help make the plant a higher-performing individual, so growers can increase their yield and performance without increasing fertilizer use
At Verdesian Life Sciences, when we think, talk, and look at developing new products, it’s always through the lens of improving NUE. How can we help growers get more out of every dollar they invest in their fertilizer? Not just for tomorrow, but for the next decade — and beyond.
Up Your Knowledge on Nutrient Use Efficiency