Nutrient Dilution—Antagonism Effects in Corn and Snap Beans in Relation to Rate and Source of Applied Potassium

Abstract

AbstractGreenhouse pot experiments were conducted to compare responses of corn (Zea mays L.) and snap beans (Phaseolus vulgaris L.) to 0 to 1,600 mg of K/pot as KNO3, KCl, and K2SO4 on K‐deficient soils (3 kg of soil/pot). Marked responses were obtained to applied K, which were similar among sources, except for a toxic salt effect of 1,600 mg of K as KCl. Marked reciprocal K‐N, K‐P, K‐Ca, and K‐Mg relationships with yield response to rates of applied K were attributed to both dilution and ion antagonism. The latter was most pronounced at higher K rates giving little or no additional yield response and resulting in decreased Ca, Mg, or P uptake. There was a close relationship between total N and total cation concentrations in corn leaves but not in bean leaves. This difference is attributed to absorption of much of the N as NO3‐N by corn and as biologically fixed NH2‐N by snap beans.