Nutrient Dilution—Antagonism Effects in Corn and Snap Beans in Relation to Rate and Source of Applied Potassium
1975
Terman, G. L. | Allen, S. E. | Bradford, B. N.
Greenhouse 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.
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