Potassium deficiency symptoms in soybean first appear as irregular yellowing on the edges of K-deficient leaves, typically manifesting as early as the V3 vegetative stage (three trifoliolate leaves), primarily on the lower older leaves (Figure 1). In severe K-deficient soils, symptoms often appear on the upper younger leaves during the reproductive stages (Figure 2). Early-season K deficiency symptoms are relatively easy to diagnose and manage. However, many soybean fields experience K deficiency and consequent yield losses without displaying visible symptoms until the later reproductive growth stages (beginning seed, R5 to full-seed, R6).

Louisiana's soybean planting progressed well in mid-April, exceeding the five-year average. However, heavy rains in mid-May slowed progress, with only 69% planted by May 12th, 2024. This lags behind last year's 76% at the same point. An article, “The Farmer's Forecast: More Soybean Planting Delays” indicates continued rain and potential wind/hail threats.

Before harvested soybeans are sold, they must be graded for quality. These inspections can be inconsistent. LSU AgCenter engineer Kevin Hoffseth is working on methods to use cameras and computers to generate a more accurate analysis of soybeans.