Ten Year Yield Response of Beardless Wheatgrass from a Single Nitrogen Application

Abstract

Forage yields were measured from 1959 to 1968 in response to a single fertilizer application in the fall of 1958 in southern British Columbia. The ten-year accumulated forage yield of beardless wheatgrass increased from 3000 pounds per acre at zero nitrogen treatment to 7750 pound per acre at 450 pounds per acre nitrogen treatment. Yield response from the lower application rates was greatest in the earlier years of the experiment. The general yield levels declined in the later years of the experiment. Nitrogen concentration in plant tops increased from 0.7 percent at the zero application level to 1.5 percent at the 450 pound application level in the first year. Nitrogen concentration gradually declined over the first eight years at the higher application rates. By the last two years, there was no effect remaining of treatment on nitrogen accumulation. Plant analyses for Ca, K, Mg, Zn, Mn and Fe showed sharp declines in Ca and Zn but only minor changes in other elements from increasing nitrogen application levels. Plant crown diameter had increased from 4.4 to 5.2 inches with increasing nitrogen rates by the fifth year of the experiment.