Productivity of Russian Wildrye and Crested Wheatgrass and Their Effect on Prairie Soils

Abstract

Crested wheatgrass (Agropyron cristatum (L.) Gaertn.) and Russian wildrye (Elymus junceus Fisch.) are used extensively as seeded pastures in the Prairie Provinces of Canada. Rangeland plowed in 1954 was planted to the 2 grasses in 1955. Herbage was harvested over a 25-year period, root weights were determined in 1977, and soil samples were obtained in 1965 and 1978 from the 2 seeded pastures and from adjacent native rangeland from each of 3 replicates. Forage production from the seeded pastures was greatest 4 years after seeding. Averaged over all years, crested wheatgrass yielded 113% more and Russian wildrye yielded 47% more forage than did native rangeland. Total root weight in the surface 15-cm layer of soil was greater on the native rangeland pasture than on the seeded pastures. Soils from native range pastures generally contained more organic carbon, less sodium, and had lower pH and sodium adsorption ratios than the soils from Russian wildrye pastures seeded 10 and 23 years before the soils were sampled. The organic C and pH's of the soils obtained from crested wheatgrass pastures decreased during the 23-year period while those of soils from the native range did not change.