An Evaluation of Factors Affecting Establishment and Survival of Russian Wildrye (\u3cem\u3eElymus junceus\u3c/em\u3e Fisch.) on Foothill Ranges in Utah

Several factors affecting establishment and survival of Russian wildrye were studied in the greenhouse and in the field. Greenhouse studies conducted at Utah State University examined (1) the effects of competition on vigor and production of Russian wildrye, (2) moisture use by Russian wildrye and four weeds, and (3) effects of moisture level on emergence and seedling vigor. During 1967 and 1969 at Tintic Valley field experiments were initiated to study effects on germination and seedling establishment of (1) seasons, (2) methods, and (3) intensities of seeding Russian wildrye. In 1968 and 1969 studies were made of phenology and root growth of Russian wildrye, crested wheatgrass (Agropyron cristatum (L.) Gaertn.) and four weeds, halogeton (Halogeton glomeratus (Bieb.) C. A. Meyer), cheatgrass (Bromus tectorum L.), Russian thistle (Salsola kali L.), and peppergrass (Lepidium perfoliatum L.), near Green Canyon in Cache Valley. At this same location in 1968, a study was conducted of field competition between Russian wildrye and the weeds. From 1964 through 1969 in Curlew Valley a field study was conducted of effects of seasons and intensities of clipping on establishment and survival of Russian wildrye and crested wheatgrass at two stand densities. Results showed that weed competition reduced vigor and production of Russian wildrye seedlings. Cheatgrass and Russian thistle competed most severely with Russian wildrye. Competition from halogeton and peppergrass also significantly reduced vigor of Russian wildrye. Peppergrass was the weakest competitor of the four. Russian wildrye, crested wheatgrass, and peppergrass were the most elaborate moisture users, making them relatively poor competitors. Russian thistle had the most extensive root system, and therefore would be a severe competitor. Cheatgrass and peppergrass were early-maturing species, and Russian thistle and halogeton were late-maturing species. Greatest competition came from a combination of either early-maturing species with either late-maturing species. Optimum planting depth for Russian wildrye was 1/4 inch. The best stand was obtained by drilling twelve pounds of seed per acre in the fall. There was no advantage of the Vinall seed over commercial seed. Failures of the Tintic Valley seedings during two consecutive years were attributed to low precipitation, variations in temperature and moisture, and lowered germination due to fungus infection of seed in the soil. Russian wildrye out-performed crested wheatgrass under all seasons and intensities of clipping at both thick and thin stand densities. Highest production and most vigorous plants came from thin stand densities of Russian wildrye and crested wheatgrass. Greatest herbage production with least reduction in plant vigor came from Russian wildrye clipped moderately in early or mid season