Nutrient management is a key go-to for unlocking production of coarse grains and forages. With each level of management adopted for top yields in corn, soybean and alfalfa, producers typically become more interested in making certain their crops lack nothing — even the difficult-to-pronounce trace element molybdenum

Molybdenum is an important factor in the nitrogen (N)-fixing ability of legumes, such as soybeans and alfalfa. Despite its minuscule dosage requirement, it plays an important role in converting nitrate N to amino acids in corn.

Small But Important

Bayer Crop Science literature explains molybdenum is rarely deficient in soils of the Midwest and has one of the lowest requirements for corn production. A 250-bushel-per-acre corn crop uses only 0.013 pounds of molybdenum per acre. In comparison, iron, another important micronutrient required by corn, would account for nearly 3.17 pounds per acre.

Independent Illinois crop consultant Ken Ferrie says most crops need less than 1 ppm of molybdenum, adding most soils naturally contain from 0.2 ppm to 6 ppm.

“Alfalfa and soybeans show a medium response to molybdenum applications, while corn has a low response,” Ferrie says. “Molybdenum availability increases as soil pH increases, and growers usually begin encountering molybdenum deficiencies in soils reading below 6.2 on the pH scale. Moly will become an issue if soil pH reaches the low- to mid-5 range.”

Showing Symptoms

Molybdenum deficiency symptoms resemble N deficiency, and because the element is immobile in the plant, symptoms show up in new growth. In soybeans, leaves will turn pale…