The following nutrient data were collected by MU Extension specialists, except for the 2011 sulfur trials.

Boron

A network of experiments measuring soybean and corn response to boron was conducted all across Missouri between 2000 and 2002. These were conducted in cooperation with the University of Missouri variety trials, mainly on farmer fields.

Average yield response to B in these experiments was very nearly zero (see table). Statistical confidence that overall soybean yield response is different than zero is 44%. There were two individually significant responses (1 corn, 1 soybean) in Mississippi River bottom soils, suggesting the possibility that these soils may be more responsive to born than other soils.

See the complete reports: Soybean (PDF) and Corn (PDF).

Sulfur

A network of experiments measuring soybean, corn, and wheat response to sulfur was conducted all across Missouri between 2000 and 2002. These were conducted in cooperation with the University of Missouri variety trials, mainly on farmer fields.

Average yield response to S in these experiments was negative except in wheat (see table). Because wheat grows mostly in cool weather, when S release from soil organic matter is slow, the chances for S fertilizer to increase yield are greater. Statistically significant yield response to S was seen at two experiments in south Missouri, where soil organic matter levels are lower than the rest of the state.

See the complete reports: Soybean (PDF), Corn (PDF) and Wheat (PDF).

In 2011, after leaving MU Extension to work for Pioneer, Julie Abendroth conducted 25 on-farm strip trials comparing yields with and without ammonium sulfate (PDF). Average yield response was zero.

Zinc

A network of 69 experiments measuring corn response to zinc was conducted all across Missouri from 2001 to 2004. Nearly all experiments were conducted in farmer fields.

Average yield response to Zn was almost zero (see table). Though corn occasionally shows early-season Zn deficiency symptoms, the evidence from these trials is that the soil will in the end supply the crop with enough zinc to make full yield.