Browsing Journal of Range Management, Volume 48, Number 5 (September 1995) by Subjects
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Effect of competition by cheatgrass on shoot growth of Idaho fescueAbility to compete with alien weeds may be one factor enabling high-seral, native bunchgrasses to persist on degraded rangelands. This study examined the effect of competition from cheatgrass (Bromus tectorum L.) on shoot growth of Idaho fescue (Festuca idahoensis. Elmer). Four Idaho fescue collections were obtained from degraded rangelands, while the fifth was from a site in high ecological condition. Plants were established in pots in a greenhouse with 2 watering regimes, and ratios of Idaho fescue:cheatgrass of 1:0, 1:5, and 1:10. Plants were grown for 56 days. Increasing competition from cheatgrass depleted soil moisture and reduced growth of Idaho fescue. However, Idaho fescue produced greater tiller and leaf numbers than cheatgrass. Idaho fescue plants from the pristine population produced 0.57 g aboveground biomass while plants from the degraded sites produced 0.31 g. Aboveground biomass from the pristine population was reduced 35% and 56% at the 1:5 and 1:10 competition levels respectively, compared to the control (1:0 ratio). Aboveground biomass of plants from the degraded populations was similar to the control at the 1:5 level, and was reduced 32% at the 1:10 level. These results indicated that Idaho fescue from the degraded sites exhibits a different response to competition from cheatgrass than Idaho fescue from the pristine site. This information may prove useful in selecting ecotypes of Idaho fescue for range revegetation.
Effect of temperature on growth of cheatgrass and Idaho fescueDevelopment of deep and extensive root systems especially at cold temperatures has been considered an advantage to successful establishment of grass species in arid environments. This study determined the effects of temperature on seedling root and shoot growth of cheatgrass (Bromus tectorum L.) and 5 collections of Idaho fescue (Festuca idahoensis Elmer). Four collections of Idaho fescue were from degraded sites while the fifth Idaho fescue collection was from a site in high ecological condition. Seedlings were grown in environmental chambers (16 hours day/8 hours night) at 5, 10, and 15 degrees C. Root depth was recorded weekly for 9 weeks, and seedlings were harvested after 63 days. Tiller and leaf number, below and above-ground biomass, and total root length were evaluated. At temperatures of 5, 10, and 15 degrees C, cheatgrass grew faster and produced a greater mass of roots and shoots than Idaho fescue. Root and shoot growth were similar for the 5 Idaho fescue collections at all temperatures. Idaho fescue collections produced more tillers than cheatgrass, except at 5 degrees C. These results indicated that cheatgrass produces greater root and shoot growth mass, but tillers less at warmer temperatures than Idaho fescue.