Growth, Yield, and Composition of Onion, Barley, and Potato Plants as Affected by Phosphorus and Ammoniacal Nitrogen Fertilization¹

Abstract

Synopsis Onion, barley, and potato plant growth was enhanced by P fertilization of a P‐deficient soil under greenhouse conditions. Variable response in growth was found, due to the source of ammoniacal nitrogen, and was in part attributable to anion competition and to the presence and severity of a minor element disorder thereby induced. The existence of anion competition and a species response difference were demonstrated by the lower P, S, and N uptake by plants in the presence of Cl from NH4Cl.