When Marion Calmer bought his first farm back in the 1980s, a quote attributed to British mathematician Lord Kelvin was top of mind: “We can’t improve on things we don’t measure or research.”

That led the Alpha, Ill., no-tiller and owner of Calmer Corn Heads to start conducting independent on-farm research, which he’s continued to make a priority in his 47 years of farming.

That commitment to testing and measuring has taught Calmer a lot about his farm and improved his profitability.

In a 2021 National No-Tillage Conference presentation, Calmer shared some of the key lessons he’s learned from his on-farm studies and the results they’ve had on his bottom line.

1. Stratification Hurts ROI

One area of his corn-soybean operation he’s continually examined over the years is his fertility program and the ROI he’s getting from applying his nitrogen (N), phosphorus (P) and potassium (K).

To test his P and K, Calmer has compared spreading the two nutrients vs. skipping an application in 60-foot-wide plots. Yield checks from two decades of the study have shown that a dollar’s worth of P and K only grows him about $0.40 worth of grain.

Considering that P and K aren’t very mobile in the soil — P only moves about 1-2 inches, while K can move about 2-3 — he suspects his application method is the reason why they’re not making…