The effect of chloride on common root rot of cereals
Common root rot is the most important root disease of cereals in western Canada and some reports have shown that chloride (Cl-) fertilization may reduce the severity of infection. In 1985, strip experiments were laid out at 36 field sites to investigate the effect of Cl- fertilization on root rot disease and crop production in Saskatchewan. At 8 sites, KCl addition depressed common root rot infection and increased grain yield of one of the crops: spring wheat, winter wheat or barley. In 1986, replicated field plot experiments were established at six sites, where spring wheat and barley were treated with different sources and rates of Cl- containing fertilizers. Generally, higher Cl- concentrations in plant tissue were found to be related to lower concentrations of plant tissue N03--N, and at one site, to reduced levels of root rot infection. Cl- fertililization did not significantly affect grain yield at any of the sites. A growth chamber experiment examined the interaction between Cl- nutrition and root rot disease under controlled environmental conditions. Spring wheat, grown on sand culture was inoculated with H. sativum fungi. As was the case in field experiments Cl- addition resulted in reduced concentrations of plant N03--N. The inoculated treatments which received KCl, NaCl and K2SO4 all had lower disease ratings than the corresponding check treatment. In a second growth chamber experiment, carried out under sterile conditions, initial infection by Fusarium spp. tended to result in higher foot rot disease ratings as compared to treatments which were initially inoculated with H. sativum.. In this experiment, disease ratings were based on foot rot infection since subcrown internodes failed to develop on the experimental plants.