INCREASE IN SEED PRODUCTION FROM NITROGEN FERTILIZATION OF NATIVE BEARDLESS WHEATGRASS
Nitrogen fertilization greatly increased pure seed yield of native beardless wheatgrass, Agropyron inerme, where the mean annual precipitation was 11 inches in the South Okanagan area of British Columbia. In one experiment in 1959, ammonium nitrate broadcast at 450 pounds of actual nitrogen per acre increased seed yield from 3.5 pounds per acre for the unfertilized plots to 17.5 pounds, a maximum increase of 400 per cent. One hundred and fifty pounds of actual nitrogen per acre increased seed yield 330 per cent and the 50-pound rate increased the yield of seed 140 per cent. At two other locations in 1961, unfertilized plots yielded 18.8 pounds of seed per acre; 150 pounds of actual nitrogen per acre increased seed yield to 59.2 pounds and the 50-pound treatment produced 46.5 pounds of seed per acre. Yield increases resulted from increases in spike production because weight of seed per spike was not increased by fertilization. Germination was not affected and per cent pure seed was slightly increased by the nitrogen treatments. This increase in seed production is considered favorable for the restoration of preferred species on depleted native range.