Response of Spring Wheat, Barley, and Oats to Chloride in Potassium Chloride Fertilizers1

Abstract

Listen

Translate article

AbstractCereal grain yield response to KCI fertilization has been reported on high K‐testing soils in the Northern Plains. Other field studies have demonstrated that wheat (Triticum aestivum L.) yield increases to CI fertilization occurred where disease incidence was high. Therefore, field experiments on high K‐testing soils were conducted over a 3‐yr period to determine the responsiveness of spring wheat, barley (Hordeum vulgare L.), and oats (Avena sativa L.) to KCI fertilization and to determine whether responses were due to K or to Cl. Experiments were conducted on soils representing Typic Argiustolls, Pachic Udic and Udic Haploborolls, and Pachic and Udic Haplustolls in eastern South Dakota. Spring wheat, barley, and oats showed grain yield increases (0.10 probability level) at four out of six, three out of six, and zero out of five sites, respectively, on soils that tested very high in ammonium acetate‐extractable K. Wheat grain yield increases varied form 0.2 to 0.5 Mg ha−1. Comparison of KCI, KNO3, and CaC12 treatments, soil analysis, and plant analysis all indicated that the yield increases on very high K‐testing soils were due to the CI in the KCI and not due to the K. Six additional wheat experiments were conducted to determine the influence of starter K and CI (applied with seed) on grain yield; however, no yield increases to CI were detected in these studies. Both KCI and KNO3 at a 20 kg K ha−1 rate significantly decreased yield at one of six sites. Other experiments showed that if sufficient CI was present in the soil or broadcast applied, no additional benefit to seed placed CI occurred. Generally, broadcast and seed placed KCI appeared equally effective. However, rates required for maximum yield at several sites were too high to be placed in direct seed contact with drill application due to potentially adverse salt effects. Grain yield increases were large enough to make KCI fertilization of these soils very economical, provided responsive sites could be predicted.