EFFECT OF POTASSIUM CHLORIDE FERTILIZATION ON TWO BARLEY CULTIVARS DIFFERING IN COMMON ROOT ROT REACTION

Abstract

The effects of potassium chloride (KCl) fertilization on common root rot severity (CRR, incited primarily by Cochliobulus sativus), chemical composition of plant tissue, and the grain yield of two barley cultivars (Hordeum vulgare L.) were studied at three locations in northern North Dakota in 1984. KCl was applied at 0, 46 and 188 kg KCl ha−1. Barley cultivars sown were Morex and Azure, with the former being the more susceptible to CRR at all sites. All sites tested ’’high’’ in available soil potassium (greater than 500 kg ha−1). Fertilization with KCl significantly reduced CRR severity of both cultivars at all sites. KCl fertilization dramatically decreased nitrate concentrations and increased chloride concentrations in the plant tissues of both cultivars. Morex accumulated more tissue nitrate than Azure at all levels of KCl fertilization. Thus, increased nitrate concentrations of the plant tissue were correlated with increased CRR severity on both cultivars. Grain yields were significantly increased by KCl fertilization at one site. Increased residual soil chloride was present after harvest at those plots receiving the high rate of KCl. The role of plant nitrate in CRR severity deserves more attention.Key words: Root rot (common), barley, fertilization (chloride), chloride-nitrate interaction, Cochliobulus sativus, Hordeum vulgare L.