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Competition between Grass and Legume Species on Dryland

Dubbs, Arthur L.
Agronomy journal 1971 v.63 no.3 pp. 359-362
botany, Plant Science and Plant Products
Two legumes and four grasses were grown in various combinations on dryland to determine the degree of competition one species exerted upon another. Species competition was measured by stand percentage, forage yields, plant height, and percent crude protein. Russian wildrye (Elymus junceus Fisch.) was the most competitive species and sainfoin (Onobrychis viciaefolia Scop.) the least under conditions experienced at this location during the trial period. Sainfoin was the only species showing a significant loss of stand during the 5-year period. The stand loss resulted from a combination of winterkilling and species competition. Grasses yielded more when competing with legumes than when competing with each other. Competition between grasses was nearly equal and no combination excelled another. Russian wildrye and alfalfa (Medicago saliva L.) were the most competitive species with sainfoin. Alfalfa plants received more competition from other alfalfa plants than from plants of other species. In general, all species were quite competitive to themselves in pure stands. Percentage crude protein of crested wheatgrass (Agropyron desertorum (Fisch.) Schutl.) increased when it was grown with alfalfa. The protein content of sainfoin was not affected by competition from any of the species. Alfalfa and Russian wildrye decreased in crude protein content when competing with smooth bromegrass (Bromus inermis Leyss.).