EFFECT OF CHLORIDE FERTILIZATION ON BEDFO RD BARLEY AND KATEPWA WHEAT

Recent studies in the northern Great Plains have confirmed that the ch loride (Cl-) component of fertilizers can reduce disease severity and increase grain yield for wheat (Triticum aestivum) and barley (Hordeum vulgare). Field studies were conducted in Manitoba in 1989 and 1990 t o determine the effect of rates of 25 and 50 kg Cl- ha(-1) (applied as KCl or NaCl) applied with or without Cochliobolus sativus inoculum on plant nutrient status, disease severity and grain yield for Katepwa w heat and Bedford barley. Chloride application, regardless of placement or source, increased the Cl- concentration in plant tissue sampled at the boot to heading stages. Rates of 25 and 50 kg Cl- ha(-1) resulted in significant reductions in the severity of common root rot for barl ey in two of six experiments and for wheat in one of four experiments. Chloride applications did not reduce spot blotch severity on barley i n either of two experiments conducted. Inoculum did not have a consist ent effect on any of the parameters measured. The application of 50 kg Cl- ha(-1) significantly increased grain yield for barley by an avera ge 393 kg ha(-1) in two of eight experiments, but did not increase gra in yield for wheat in any of eight experiments, Yield responses to Cl- were not related to soil Cl- content, Cl- concentration in plant tiss ue or observed reductions in disease.