Phosphorus placement may be a factor. McFarland said injection “works extremely well with a substantial response. Producers may reduce the soil test recommendation rate in half. A 60 pound per acre broadcast ate may be reduced to 30 pounds injected. Injection is particularly effective in wheat, especially forage wheat.”

He recommends injection 4 inches to 6 inches beside and below the seeded row.

He said turning the soil to incorporate phosphorus may be effective but is not economical “with the current cost of energy.”

Potassium, McFarland said, “is extremely important. Corn needs more potassium than nitrogen. Potassium may occur naturally in the soil and a sample from 6 inches to 18 inches may show producers they don’t need as much as they might have thought. Deep sampling can save money at current potassium prices. It’s expensive.”

He said renovation time for pastureland is a good opportunity to apply potassium.

Micronutrients zinc and iron also play important roles in plant growth and health. He recommends testing for micronutrients every three to five years. “Don’t get to deficiency, however. By that time, damage has been done.”

He said some farmers may consider alternative fertilizer sources such as manures, composts and biosolids. “The value depends on the nutrient content. Biosolids may have a guaranteed analysis; the others do not, so have them tested.”

He said price of these alternative nutrients may be pretty good. “But farmers may need a nitrogen booster. Compost and manure value may also depend on the animal it came from and how the material is handled. He said broiler litter provides a fairly good nutrient analysis and is often a good buy.

“But test the material then do the math to determine the cost per pound of nutrient.”