Vegetative stabilization of retorted oil shale on a steep, south-facing slope in Northwestern Colorado

This study was designed to determine the feasibility of vegetative stabilization of Union Oil Company Process B retorded shale on a 57% south-aspect slope. Treatments consisted of Process B retorded shale, soil over Process B shale and soil over subsoil, all seeded with a mixture of native grasses, forbs and shrubs. Parameters examined were vegetative cover, run-off quantity and quality and salt movement within the profiles. After three growing seasons, total vegetative cover was similar for all treatments. Vegetation composition had made a strong shift from grasses and forbs toward shrubs by the third growing season. The major species on all treatments was fourwing saltbush ( Atriplex canescens). Examination of salt movement in the profiles indicated a significant accumulation of salt after three growing seasons at the 30–60-cm depth range in Process B shale treatments.