Effect of seeding date and seeding rate on malting barley production in western Canada

O'Donovan, J. T., Turkington, T. K., Edney, M. J., Juskiw, P. E., McKenzie, R. H., Harker, K. N., Clayton, G. W., Lafond, G. P., Grant, C. A., Brandt, S., Johnson, E. N., May, W. E. and Smith, E. 2012. Effect of seeding date and seeding rate on malting barley production in western Canada. Can. J. Plant Sci. 92: 321-330. Barley (Hordeum vulgare L.) growers in western Canada often have difficulty achieving malting grade. This is usually due to unfavourable climatic conditions, but sub-optimal agronomic practices may also be a factor. Field experiments were conducted in 2006, 2007 and 2008 at eight locations in western Canada (24 site-years) to evaluate the effects of seeding date (relatively early and late) and seeding rate (100, 200, 300, 400 and 500 seeds m(-2)) on AC Metcalfe barley yield and malt quality parameters. Delayed seeding often resulted in negative effects including increased protein concentration, decreased kernel plumpness and yield. However, at 6 site-years, higher yields occurred at the later seeding date. 300 seeds m(-2) was usually optimal; maintained or improved yield, decreased protein concentration, increased kernel uniformity and time to seed maturity, and decreased tillering. In most cases, seeding at more than 300 seeds m(-2) did not result in an improved outcome, and there was a risk of reduced yield and kernel plumpness at rates above this level. A multivariate analysis indicated that relatively low barley plant densities were associated primarily with northern locations with low soil pH.