As no-tillers are pressured to get the most from every acre and input dollar, it would be wise to consider how profitability is being measured.

It might be tempting to pull out yield-map data and pore over it. But the best way to find out if input decisions are profitable is by measuring the yield response — not just yield data alone, says Peter Kyveryga, senior research associate for the Iowa Soybean Association.

“Often we use the terms ‘yield’ and ‘yield response’ interchangeably,” Kyveryga told attendees at the ISA’s On-Farm Network Conference earlier this year. “But yield response is a yield change from increasing levels of various inputs or using a new technology or management practice.

“Yield response is obtained or estimated under specific conditions, such onfarm replicated strip trials.”

Defining Yield Response

A chief goal of examining yield response is to ascertain whether a specific practice is profitable or not.

An example, Kyveryga says, may be a no-tiller raising an average soybean yield of 45 bushels an acre who sprays a fungicide that results in a 4-bushel-per-acre yield response.

With the fungicide costing $20 an acre and soybean prices at about $15 a bushel, the value of additional yield is $60 an acre and the profit from fungicide use would be $40 an acre.

“In that example, the grain value and profit didn’t depend on yield,” Kyveryga says. “It doesn’t matter if the yield is 30, 40 or 80 bushels.”

Straight yield data is useful for some tasks, like…