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area. Results from these investigations provide evidence indicating <br />that the application of mulch would not be beneficial. <br />Application of either straw or annual grain mulches intercepts much of <br />the needed plant moisture and renders it unavailable for plant growth. <br />Various researchers have documented this fact. On the Northern Great <br />Plains, ARS -NDSU (1975) reported that application of straw <br />signficantly lowered the amount of plant available moisture. Plots <br />receiving straw were found to contain a negative 0.01 inches of water <br />while the same plots receiving no straw contained 1.03 inches of <br />water. In Colorado's Piceance Basin, researchers at Colorado State <br />University (1978) reported that application of mulch significantly <br />reduced grass and forb densities and grass heights. They concluded, <br />"there appears to be an overall depressing effect of silva -fiber mulch <br />on grass and forb establishment ". During the second year of this <br />study, Colorado State University (1979) researchers concluded that, <br />"mulch may retard the establishment of grasses in both the native and <br />introduced grass and grass forb mixtures. In terms of biomass, it was <br />reported that, mulching has no significant effect on the biomass of <br />seeded plants ". <br />Similar conclusions relative to the negative effect of straw or annual <br />grain mulch on plant growth and survival are demonstrated in another <br />study conducted in Western Colorado by researchers of the USDA. <br />Frischnecht and Ferguson (1979) reported that first year survival of <br />transplanted shrubs and forbs on processed oil shale was highest on <br />treatments receiving topsoil (82 percent) and lowest on plots <br />receiving barley straw (36 percent). Not only was plant mortality <br />highest, but also plant heights lowest on plots receiving barley <br />straw. <br />Another study conducted in western Colorado (Rio Blanco Oil Shale <br />1976, 1977 and 1978) revealed that application of straw, straw netting <br />or hydro -mulch did not increase seedling survival of planted species. <br />2.05 -46 <br />