In episode 10 of Corn College TV, Farm Journal Field Agronomist Ken Ferrie explains how phosphorus is available to the corn plant like a drip IV.
“We try to make our best guess how much phosphorus is available to the plant,” Ferrie says. “This is determined by microbial activity in the soil itself. The soil test may give you a measurement of phosphorus, but if you look at the levels at any one time, it’s so tightly held by the organic matter, the soil cations, and microbial populations that is more like a drip IV.”
Soil pH is key to phosphorus availability because if soil pH is too high or too low, the nutrient will not be available to the plant. In high pH soil, Ferrie suggests banding the phosphorus application instead of broadcast application. Also, starter fertilizer can help with the timing and placement of the nutrient close to the root system for availability early in the season.
Learn more about phosphorus availability and application options in episode 10 of Corn College TV.