WEED MANAGEMENT IN SPRING BARLEY (HORDEUM-VULGARE) IN THE ABSENCE OF HERBICIDES

Field experiments were conducted in 1990 and 1991 at Scott, Saskatchewan to determine the effect of row spacing (11, 22, 33, 46 cm) and seeding density (50, 90, 150, 220 kg ha-1) on the ability of spring barley to compete with weeds. Barley yield was greatest with narrow row spacings and increased seeding densities, however there was no spacing X density interaction. Biomass production of wild oats (Avena fatua L.), wild mustard (Brassica kaber (D.C.) L.C. Wheeler) and volunteer canola (Brassica campestris L.) were significantly reduced by both narrower row spacings and increased seeding densities, but there was no row spacing by seeding density interaction. Adjusting barley rows from 46 to 11 cm produced yield increases over all densities of 77 and 67 percent in 1990 and 1991, respectively. Similarly, increasing the seeding density from 50 to 220 kg ha-1 resulted in yield increases of 80 and 93 percent over all spacings in 1990 and 1991, respectively.