Laserfiche WebLink
4.4.1.7 Shrub Establishment Test Plots <br /> Introduction and General Study Description. Shrub establishment demonstration plots <br /> were established at Trapper Mine during the fall of 2000. The test plots were established <br /> in cooperation with the Colorado Division of Minerals and Geology (DMG) and <br /> researchers with Colorado State University (CSU). The goal of the plots was to evaluate <br /> cost effective methods for establishing native shrubs on reclaimed lands. <br /> Native shrub establishment on reclaimed lands in northwest Colorado has been a <br /> challenge. Competition from herbaceous species and wildlife browsing present <br /> significant obstacles. The uniform replacement of topsoil, at depths ranging from 12-20 <br /> inches, may be another factor contributing to the homogenous grass community structure. <br /> Grasses thrive at the expense of forb and shrub species. The young shrubs that do get <br /> established are highly desirable browse for deer and elk. Thus, heavy browse pressure <br /> creates another limitation for shrub establishment. <br /> In an effort to overcome these limitations, a study design was developed. Six treatment <br /> plots were established to evaluate shrub establishment techniques that have commercial <br /> practicality on a large scale. The specifics of the Trapper demonstration plots are <br /> presented in the Field Trial Details section of this narrative. <br /> The study design took into consideration the possible limitations to shrub establishment. <br /> To evaluate the effect of herbaceous competition, seed mixes were designed so that <br /> shrubs contributed the majority of the seed mix. Two seed mixes were evaluated: 1) a <br /> native grass, forb and shrub seed mixture and 2) a seed mixture of unpalatable native <br /> shrubs and low-competitive native grasses and forbs. One treatment included alternating <br /> strips seeded with only the shrub/forb component of the mix. The depth of topsoil on the <br /> plots was varied to evaluate shrub and forb response to topsoil depths ranging from 0 <br /> inches to 20 inches. <br /> Composite soil and overburden samples were taken from each treatment. Overall, the <br /> soils (topsoil and spoil) had good physical and chemical properties. Soil pH ranges from <br /> 6.9 to 7.7, macronutrients appear to be adequate for sustained plant growth, organic <br /> matter contents are relatively high (4.8% to 6.5%), salt levels are low (EC ranges from <br /> 0.6 to 1.6 mmhos/cm and SAR ranges from 0.6 to 1.8), cation exchange capacity (CEC) <br /> is in a normal range, and textures are clay loam and sandy clay loam. Overall, both <br /> topsoil and spoil have favorable characteristics and provide a suitable plant growth <br /> medium. <br /> To evaluate the impact from wildlife browse, elk proof fencing was constructed on one- <br /> half of each treatment. <br /> 4-124 <br /> APPROVED MAY �C 6UJ <br />