High fertilizer costs are forcing farmers to look harder at every pound of phosphorus and potassium they plan to apply this fall. On the Precision Technology Institute (PTI) Farm near Pontiac, Ill., Jason Webster and team are testing whether changing fertilizer placement — and cutting application rates — can help preserve profits without sacrificing too much yield.
Preliminary results from the first five years of a 10-year study comparing banded and broadcast dry fertilizer suggest the savings can be substantial, says Webster, lead commercial agronomist for Precision Planting, who manages and directs the PTI Farm.
“Our data would say we can reduce the rates of fertilizer without missing a beat yield-wise or economic-wise,” Webster reported in fall 2025. “We can actually make more money on a per-acre basis if we band the fertilizer at reduced rates, given where commodity prices are at, as well as fertilizer prices.”
The findings raise an important question: How long can farmers rely on existing soil fertility before drawing down the bank begins to cost them more in lost yield than they save on fertilizer?
Testing Fertilizer Placement and Rates
The 10-year study compares conventional broadcast application with banding phosphorus and potassium beneath the row in a strip-till system. The banded fertilizer is placed about 8 inches deep, concentrating nutrients near the crop rather than distributing them across the field.
The trial includes five application rates: 100%, 75%, 50%, 25% and zero of the soil-test-recommended rate for a yield goal of 240 Bu/A corn in a corn/soybean non-irrigated rotation. Researchers determine the full recommendation using post-harvest soil samples and the yield goal, then compare yield and economic results across treatments.
The zero-fertilizer treatment receives no phosphorus or potassium in the same strip year after year, allowing Webster and his team to track how soil-test levels and yields change as the crop draws on existing fertility.
After four harvested crops without fertilizer in that strip, evaluated in fall 2025, soil-test phosphorus declined from 67 to 45 pounds per acre. Soil-test potassium levels fell from 390 to 334 pounds per acre.
The declines show that the corn crop is drawing down the soil nutrient supply, although the changes have been relatively modest so far, in Webster’s opinion.
Those starting soil-test levels are important context for interpreting the results. The study is examining how far the farm can reduce fertilizer applications while drawing on existing nutrient reserves — not whether corn can yield well indefinitely without phosphorus and potassium replacement.
Five-Year Results Showcased
Results from the first five years of the study (2021–2025) show that banded dry fertilizer produced positive yield gains compared with broadcast fertilizer at every application rate.
The economic advantage was strongest at the 50% and 75% banded rates. Over the five-year period, those treatments generated additional returns of $23.78 and $18.72 per acre, respectively, compared with broadcasting fertilizer at corresponding rates. The 100% banded rate produced an average gain of $14.16 per acre, while the 25% rate generated an advantage of just 94 cents per acre.
The 2025 results, specifically, show why yield gains alone don’t tell the whole economic story.
Banded fertilizer increased yields by 0.2 bushel per acre at the 100% rate, 3 bushels at 75%, 6.2 bushels at 50% and 0.3 bushel at 25%, compared with broadcast fertilizer at the corresponding rates.
However, University of Illinois machinery cost estimates put the additional cost of strip-till at $12.80 per acre compared with a conventional-tillage program. After accounting for that additional cost, the 100% banded rate returned $3.67 per acre less than the conventional-tillage comparison. The 75% and 50% rates generated gains of $3.85 and $11.90 per acre, respectively, while the 25% rate resulted in a $14.85-per-acre loss.
The results underscore the importance of evaluating fertilizer placement, application rates and tillage costs together.
Although banding produced yield advantages at every rate over the five-year period, those gains did not translate into the same economic return across treatments.
The 50% and 75% rates delivered the strongest five-year economic advantages in the reported comparison. In 2025, they also performed better economically after accounting for the additional strip-till cost.
Strip-Till Offers Flexibility
For the PTI Farm, strip-till provides both a tillage system and an effective way to place fertilizer precisely. Webster says roughly 90% of the farm’s tillage program uses strip-till, giving the operation the flexibility to band nutrients and adjust rates as economics change.
He emphasizes that the approach does not eliminate farmers’ need to monitor soil fertility. Instead, it gives them another management consideration when fertilizer costs are high and existing soil nutrient levels can support crop production.
Webster says the company plans to continue the study to determine when the balance changes — and when declining soil fertility begins to reduce yields enough that additional fertilizer becomes economically justified.
For farmers evaluating fertilizer programs for 2027, the findings reinforce the value of making nutrient decisions field by field. Soil-test levels, expected nutrient removal, fertilizer prices, grain-price expectations and application method all affect whether another pound of phosphorus or potassium is likely to pay. The study also highlights the need to weigh immediate fertilizer savings against the longer-term cost of drawing down soil fertility.
Webster says the goal, ultimately, is to help farmers remain flexible and viable in a market where they have little to no control over either fertilizer costs or grain prices.
“I can’t do anything about the cost of fertilizer. I can’t do anything about the price of corn,” Webster says. “But I can be efficient in the way I’m applying fertilizer.”
Learn more about the 10-year PTI Farm study and the results found so far at the link below:
