The best way to minimize fertilizer expenditure and maximize efficiency is one you’ve probably heard of before. The 4Rs — right product, right rate, right time and right placement — tell you exactly how to accomplish this.
Agronomically, following the 4R best practices keeps corn plants from ever experiencing a bad day — and that’s the key to maximizing your crop’s yield, explains Farm Journal field agronomist Ken Ferrie, who cites decades of Farm Journal Test Plot studies.
To help corn plants get off to a good start, they must have sufficient nutrients available to maximize early season growth. Even one stressful day could cause them to dial back their yield. Soybeans, in contrast, are able to overcome some degree of early stress, but it’s important for them to have adequate nutrients during pod-fill in August. This is an example of how timing (the fourth R) comes into play.
“Phosphorus is one of the most important early season nutrients,” Ferrie says, “It drives cell division and elongation.”
Here are seven tips to better manage your phosphorus (P), confirmed by years of the Farm Journal Test Plot program:
- Feed Phosphorus Early. “Unlike soil phosphates that must be mineralized by soil microbes, planter-applied fertility is readily available and not sensitive to temperature,” Ferrie says. “The quicker plant roots meet up with starter fertilizer, the faster you’ll see a response: deeper green color and taller plants.”
- Place Phosphorus Below the Surface. “Compared to nitrogen and sulfur, phosphate is slower to move through the soil,” Ferrie says. “It must be put where roots will grow into the band. On the surface, phosphate may not be picked up unless and until brace roots encounter it.”
- Weigh In-Furrow Pros and Cons. “In-furrow applications trigger the quickest response,” Ferrie continues. “But because of the danger of salt injury, be careful with the rate and quality of product. Low in-furrow rates may not have enough push to get corn to knee-high when nutrients will be mineralized from the soil.”
Use Banding Methods. “Banding phosphate 2" below and 2" beside the furrow is safe, and rates can be high enough to push corn to waist-high,” Ferrie says. “But a 2x2 application is slower to kick in than an in-furrow application.”
There is a way to work around this, though.
“Attachments such as the Huckstep Fertilizer Shoe and the 360 Wave place fertilizer closer than 2x2 — more like ½" to ¾" beside and below the row,” Ferrie says. “This allows for a higher rate without concern about salt burn, and it’s close enough to the roots to eliminate the need for an in-furrow application.”
- Double Up on Phosphorus Placement. “Many growers use a relay treatment,” Ferrie says. “They put a light rate of phosphate in the furrow as a pop-up and band a higher rate 2x2. That provides enough phosphorus to carry the plants to waist-high, when soil mineralization has kicked in.”
Explore Equipment Options. Among many equipment options for effective P placement, besides the Huckstep and the Wave, are the Furrow Jet and the Yetter 2968 Fertilizer Opener.
“Picking the right attachment for your planter and soil type is the key,” Ferrie says.
- Add Zinc for Better Uptake. “Zinc is a co-enzyme that helps lift phosphate into the plant cells,” Ferrie says. “Whenever we use it in our test plots, we get a more consistent response to the phosphate. If you feel zinc is too expensive, pull back your starter rate until the zinc application fits your budget.”
This Farm Journal study examined the 360 Wave fertilizer attachment in two soil types. The Wave performs two functions: improving seed trench closure and injecting starter fertilizer beside and below the seed. In each soil, improving seed trench closure improved yield, compared to the planter’s standard closing system, and injecting starter fertilizer increased it further.
“There are many equipment options for improving starter fertilizer placement,” Ferrie says. “The key is to find the right one for your planter and soil type.”
This 2024 Farm Journal study in central Illinois demonstrated the value of adding zinc to your starter fertilizer.
“Zinc helps lift phosphate into plant cells,” Ferrie says.
In this instance, adding zinc increased the yield by 4.5 bu. per acre. Tissue testing revealed that adding zinc to the starter also increased the nitrogen and zinc content of the plants.
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