Potassium accumulation and soybean yield related to potassium fertilizer rate and placement

Abstract

Abstract Sandy coastal plain soils have relatively low reserves of potassium (K) and may not be able to supply adequate K for intensive soybean [Glycine max (L.) Merr.] production. Field experiments were conducted in 1985 on Goldsboro sandy loam (fine‐loamy, siliceous, thermic Aguic Paleudult) and in 1986 and 1987 on Dothan loamy sand (fine‐loamy, siliceous, thermic Plinthic Paleudult) to determine K fertilizer rate and placement effects on soybean growth and seasonal K accumulation. Treatments were 0, 56, 112, 168, and 224 kg/ha broadcast and 56 kg K/ha banded plus 0, 56, 112, and 168 kg/ha broadcast. Seasonal plant tissue K concentrations were generally increased by K fertilizer rate each year. Method of placement did not have consistent effects on plant K concentration and had little effect on total K accumulation. Grain yield responded to applied K only in 1986 when the initial exchangeable K level was 0.24 cmol/L. Both broadcast and broadcast‐plus‐band placement methods resulted in linear yield incre...