How to Approach the 4Rs of Nutrient Stewardship in 2023

Treating your farm like a business and understanding the return on every investment is everything.

On that note, devote the same amount of time and attention to detail on the 4Rs of nutrient stewardship as you do on seed choice, says Curt Woolfolk, Senior Manager, Crop Nutrition Technologies, The Mosaic Co. A deep discussion with your trusted advisor to challenge your traditional approaches around the right source, right rate, right time, and right place can increase yields and profitability, all while decreasing the potential for environmental impact, he says.


“Seed selection is a significant part of farm profitability, but it’s only one part of the equation. Up to 60% of your yield is dependent on soil fertility,” he says. Woolfolk also notes that while nitrogen often takes center stage, phosphorus and potassium are equally important when it comes to the big three.

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Farmer sentiment has improved in early 2023, according to the Purdue University-CME Group Ag Economy Barometer Index. More specifically, January survey results pushed the index 34% above its 2022 low point which occurred last June.

Nonetheless, there is a natural tendency for people to want to cut rates on fertilizer, particularly in this high-inflation environment, agronomists acknowledge. Likewise, applying nitrogen above university recommendations is also a problem that can substantially reduce returns, agronomists point out.

Keeping nitrogen rates at maximum return to N results in the most profit, says Dr. Gary Schnitkey, Professor and Extension Specialist at the University of Illinois Urbana-Champaign. For this state, that means 157 pounds per acre for Northern Illinois, 166 pounds for Central Illinois, and 185 pounds for Southern Illinois. “If we’re above those rates, we can increase profits by reducing rates,” he adds.

Remembering the 4Rs of Nutrient Stewardship

Many of today’s corn hybrids have a relative maturity between 90 to 120 days. About half of the phosphorus needed by the plant is taken up until the tasseling stage, with the other half used by the plant from that point until physiological maturity. Woolfolk uses the analogy of nutritional requirements in a person’s meals throughout the day to show that feeding the plant a massive breakfast (at planting) and nothing else is not an ideal approach. Solving this issue — how best to “spoon-feed” a crop throughout its life cycle — has been a major focus for the company’s research and development team, with the goal of helping growers address the 4Rs of nutrient stewardship.

“When it comes to feeding the crop at later growth stages, we often don’t have the equipment that can come in over the top without crop damage. Dry granular fertilizers that can offer a slow-release mechanism for nutrients can help feed crops throughout the season,” which is exactly what Mosaic did with its MicroEssentials line, a bestseller for the company for the past 15-plus years. MicroEssentials granules provide uniform nutrient distribution of phosphorus, sulfur, and even zinc, while providing increased nutrient uptake and two forms of sulfur for a season-long sulfur supply.

Brittany Loewen, Corteva Agriscience Nutrient Maximizer Sales Leader, highlights the importance of using a nitrogen stabilizer like N-Serve or Instinct NXTGEN. The active ingredient in both products is called Optinyte technology, which was first introduced to the market about 46 years ago and is proven to increase corn yield potential by an average of 5.2% when used with spring nitrogen applications and by 7% when used with fall applications.

Up to 70% of nitrogen loss occurs below ground, which is where these stabilizers have proven to work, by increasing soil nitrogen retention by 28% and reducing leaching by 16% — the equivalent of 21 million pounds of nitrogen prevented from entering waters in the U.S. each crop year, according to Corteva.

“It’s a win-win-win when it comes to doing what’s best for the crop, what’s best for the environment, and what’s best for our farmer’s bottom line,” Loewen says. “No matter what rate you’re using, no matter what form of nitrogen you’re using, you should be thinking about how you can incorporate a stabilizer in your fertility program. You want to protect it, and make sure that it’s there in the root zone when you’re crop needs it the most, which is actually much later in the season than when we are typically applying nitrogen.”

For the fourth-generation family-owned Kugler Co. in McCook, NE, following the 4Rs has been a deeply ingrained part of the company over the past 40 years, John Kugler, Co-President, tells CropLife®.

“Our area utilizes the 4Rs just as good as anybody across the country because of our moisture situation and water availability, and I think we do a good job,” he says. “There haven’t been a lot of changes in the ag business. There are a lot of newcomers to this business preaching a new story, but it always winds up going back to feeding the plant to make yield.”

Kugler’s signature product is its KQ-XRN, a proprietary nitrogen (28-0-0) formulation with 72% slow-release nitrogen, foliar applied at between V5 and R3 corn growth stage. The product increases chlorophyll on the leaf due to the 28% nitrogen present, causing an increase in the rate of photosynthesis, which further boosts plant water uptake from the soil.

“In essence, we’re trying to feed the plant a little bit all the time. There are still some parts of the country that have growers applying 200 pounds of N and call it a day till they harvest. That’s not how it works anymore out here,” he adds.

Clara Milsaps, Senior Advisor, Regional Agronomy with Nutrien Ag Solutions, says that years like 2022 encouraged innovation with common sense using crop and soil management decisions that often provide fresh insights, resulting in new practices.

“A turning point in conversations this year has been assessing how much nitrogen it took to produce a bushel of corn, bale of cotton, or bushel of wheat on a particular field,” Milsaps tells CropLife. “Depending on geography and lab, N recommendations can range from 1 to 1.2 pounds N per bushel of corn. Our approach to nutrient stewardship is to challenge ourselves by examining methods to tighten nutrient use efficiencies in order to help growers sustainably grow more per acre.”

Paul Bonnett, Senior Director of Agronomy and Environmental Science at Nutrien Ag Solutions, suggests a 5th R: Review.

“First and foremost, always review fertilizer and soil fertility rates, sources, timing, and placement. Do the proposed rates support your yield goals? If nutritional deficiency symptoms occurred during the season, Nutrien Ag Solutions considers all the parameters that could explain them, including weather, accumulated stress, soil compaction, or outright low soil test values,” Bonnett explains.

Prescriptive Application

A best practice highlighted by The Fertilizer Institute is grid soil sampling of all acres for variable rate application of nutrients to help determine the right rate and right placement.

A survey of precision ag retailers conducted by CropLife magazine in conjunction with Purdue University, found that by 2025, use of variable rate fertilizer by retailers will reach 93%, and use of variable rate pesticide by retailers will reach 56%.

With prescriptive application, readily available data such as soil type, elevation, CEC, pH, OM, satellite imagery, and field history, are used to create a shapefile, which then guides a unique application system to apply crop inputs in-furrow precisely and variably.

SIMPAS-applied Solutions and the SIMPAS application system allow farmers, agronomists and retailers to be versatile with multiple crops, multiple products, multiple strategies and multiple planters,” Jim Lappin, Director of SIMPAS Portfolio and Alliances at AMVAC, said at the company’s Technology Summit road tour in Rockford, IL, in September. “This method allows data to drive at-plant input decisions, offering peace of mind that growers are planting strategically to yield optimal results and increase profit potential.

AMVAC also recently expanded the SIMPAS-applied Solutions portfolio with the addition of MicroSync Pro MINI, a combination nutrient formulation that improves soil fertility programs by providing a precise balance of critical nutrients formulated to prevent or correct deficiencies of boron, manganese, sulfur, and/or zinc. This uniform granular fertilizer is activated by soil moisture, creating millions of particles within the root zone to enhance nutrient conversion and allow uptake, so the crop starts strong.