Banded Fertilizer and Rate Reduction Study: 5-Year Findings from a 10-Year PTI Farm Trial
The PTI Farm initiated a 10-year field study to compare banded dry fertilizer applications against traditional broadcast methods. A core part of the trial also tests how far fertilizer rates can be reduced without sacrificing profitability, including 25%, 50%, 75%, and even 0% application rates.
Study goal and setup
This research evaluates two key questions: whether placing fertilizer in a band can outperform broadcast application, and whether reduced fertilizer rates can maintain returns while managing input costs. The study tracks both short-term profitability and longer-term impacts on soil test levels as the trial progresses.
Starting soil test levels
At the beginning of the study, soil test levels were considered adequate. Phosphorus was measured at 66 lbs/acre and potassium at 363 lbs/acre.
Corn profitability: year-by-year results (2021–2025)
Year 1 (2021): Banding fertilizer with a 25% to 50% rate reduction produced a $50 net gain per acre. Even the 0% fertilizer treatment increased returns by $8 per acre compared to a 100% broadcast rate.
Year 2 (2022): Net returns continued improving, with 0% fertilizer yielding nearly $40 more per acre.
Year 3 (2023): A 25% rate reduction generated a $14 per acre gain. The 0% fertilizer treatment still showed nearly a $20 gain.
Year 4 (2024): A $66 per acre gain was observed with 0% fertilizer, largely driven by high fertilizer costs.
Year 5 (2025): The 0% fertilizer treatment resulted in a $20 per acre loss. However, a 25% to 50% rate reduction still delivered roughly a $30 per acre gain.
Impact on soil test levels after five years
As expected, the most aggressive rate reductions affected phosphorus more than potassium.
Phosphorus: In the 0% fertilizer plots, soil test phosphorus declined from 66 lbs/acre to 25 lbs/acre.
Potassium: Potassium levels remained relatively stable across the period measured.
Soybean profitability: 5-year summary
Across five years of soybean data, applying 0% fertilizer resulted in an average yield loss of 3.3 bushels. Even so, the 0% rate was identified as the economic optimum rate over that span. The study also found that a 50% fertilizer reduction applied in a band was economically beneficial.
What these early results suggest
Through the first five years, the trial indicates that band placement can improve nutrient efficiency and reduce the amount of fertilizer required to stay economically competitive, especially in years when fertilizer prices are elevated. At the same time, the drop in soil test phosphorus in the 0% plots highlights the long-term tradeoff that needs to be monitored as the 10-year study continues.
