Soil adsorption interactions of band-injected anhydrous ammonia and potassium chloride fertilizers

The fertilizers were injected separately and simultaneously into two soils, a Hoytville silty clay loam (fine, illitic, mesic Mollic Ochraqualf) and an Avonburg silt loam (fine-silty, mixed, mesic Aeric Fragiqualf). Following incubation for various periods, in the Avonburg soil, very little interaction between the two fertilizer materials was observed; in the Hoytville soil, AA and KCl had little effect on NH₄ ⁺ distribution, compared with AA injected alone. Relative to KCl injected alone, simultaneous injection of AA and KCl in the Hoytville soil increased exchangeable K⁺ and decreased fixed K⁺ within 3.0cm of the injection point. Decreased K⁺ fixation was attributed to preferential NH₄ ⁺ fixation blocking K⁺ fixation; increased exchangable K⁺ was attributed to pH-induced increases in cation-exchange capacity and to decreased K⁺ fixation. -from Authors