OMAHA (DTN) -- Plenty of phosphorus (P) fertilizer application is still broadcast, but more farmers are moving toward banding or knifing in their fertilizer needs directly into the soil. The appeal of this process would be improved fertilizer efficiency, but it does also create a need for specialized application equipment.
Ted Hamer, Traer, Iowa, bands in P as well as potash (K) on his strip-till corn acres. "We put it in the strip pre-plant and then plant on the strip," Hamer told DTN. "I like it for the added nitrogen to get corn started."
Charles Shapiro, University of Nebraska-Lincoln (UNL) Extension soil scientist, has done several long-term studies looking at knifing in P. His unpublished data has yielded mixed results, but some general trends can be gleaned from his studies conducted at the Haskell Agricultural Laboratory located near Concord in northeastern Nebraska.
One study, done since 2000, examines the effect of P rate and placement -- one as a starter, another broadcast and a third knifed into the row. All three treatments used rates of 34 pounds of P per acre, 68 lbs. of P/acre and 10-34-0.
Shapiro knifed in P fertilizer between the 30-inch rows after planting once the dryland corn is a few inches tall. He found higher yields in the knife treatment compared to the starter fertilizer and the broadcast application, though just slightly higher.
"The increases are not that significant, but in that 8- to 10-bushel-per-acre range, and they are pretty consistent year to year," Shapiro said.
In addition to higher yields, Shapiro's studies also showed the knife treatment led to higher P levels in the soil.
The five-year average (2007 to 2011) showed the knife treatment at 68 lbs. had 38 parts per million (ppm) of P in the soil. The broadcast method at 68 lbs. had 20 ppm of P while the starter placement at 68 lbs. had 21 ppm of P.
The slight increase in corn yields by knifing P is probably not enough for farmers to completely alter how they apply P. The economics also don't seem to be in one's favor when increasing P rates to higher levels, Shapiro said.
Shapiro has found P levels past 15 ppm in his northeast Nebraska soils did not show much of a yield increase at the higher ppm levels. Essentially, the added expense of more nutrients applied to the soil to get to these ppm levels would not be paid for by a large yield increase.
MORE BANDED P?
Farmers appear "a bit" more interested in banding P fertilizer in recent years, according to Adam Spelhaug, agronomy/product manager for Peterson Farms Seed located in Harwood, North Dakota. However, banding nutrients is not a completely new idea in North Dakota.
"We've had guys deep banding their non-mobile nutrients (P and potash [K]) in the fall for a while now in their corn acres," Spelhaug said.
Spelhaug said banding P fertilizer has several positive agronomic and economic advantages.
Applying P in this method gives good placement of the nutrient for the young corn plants to use right when they need it. In addition, less fertilizer can be used as application rates can be cut by a third to a half and the grower can still maximize yield, he said.
The downside of banding P is working out the logistics of more trips across the field if the weather is uncooperative, Spelhaug said. In addition, different application equipment is needed to band fertilizer.
Hamer, the Iowa farmer, said the only negative aspect he has found with banding P in his strip-till corn acres is if the soil is dry when P is applied -- the salt in the fertilizer might burn the seedling and reduce the stand. However, he said the efficiency that comes with applying fertilizer and limiting erosion using strip-till outweighs the bad in banding nutrients.
His banding application tool is a Dawn Pluribus machine with coulters. This practice has allowed him to plant corn into a warmer, drier and more nutrient-rich seedbed.
Hamer has been strip-tilling some of his corn acres for about seven years, but most of his acres will be strip-tilled for the 2017 growing season. He continues to tweak practices. He used to strip-till while he applied anhydrous, but once he tried banding P and K, he moved his anhydrous application to a side-dress operation.
OTHER P OPTIONS
For those farmers who have not adopted strip-till, Spelhaug said there are benefits of banding fertilizer if you are in a no-till or minimum-till system. Banding nutrients can also be accomplished by utilizing the corn planter.
"I'm a big believer of in-furrow starter-placed P," Spelhaug said. "We're not trying to fulfill the full needs of the plant with this method, so we only need rates from 3 to 5 gallons/acre of 10-34-0, which are safe to the corn seed as well."
Farmers considering adopting banding P also should consider the ramifications of using liquid P versus dry P. The cost per pound is less expensive with dry fertilizer, but dry may be harder to move and apply than liquid P, depending on the operation, Spelhaug said.
Spelhaug said he would recommend farmers zone test their soils to see where in the field P is actually deficient. In his experience, farmers he has worked with have gotten by with little or no applied P other than in the starter, he said.
Russ Quinn can be reached at firstname.lastname@example.org
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