The Establishment of Cheatgrass (Bromus Tectorum L.) on Spent Oil Shale from the Paraho Process

Experiments were conducted in a greenhouse with the following objectives: (i) to study the emergence and seedling growth of cheatgrass ( Bromus tectorum L.) in soil and in Paraho spent oil shale that was either leached, treated with sulfuric acid, covered with soil, or mixed with soil, and (ii) to study emergence and seedling growth of cheatgrass on spent shale that was fertilized with ammonium nitrate and triple superphosphate. The EC e of the spent shale was 14 mmhos/cm, the pH was 9 and the shale was low in plant available N and P. The soil from Federal oil shale lease tract U‐a near Bonanza, Utah was a coarse textured alluvium with low moisture retention. Cheatgrass planted on soil alone and shale covered with soil had the highest emergence rates (75–86%) and produced the greatest total biomass (8.55–13.4 g). Seedling emergence rates on leached and unleached spent shale were 44% and 36%, respectively, and total biomass was <1 g on either treatment. Seedlings failed to emerge on sulfuric acid‐treated spent shale. The addition of sulfuric acid to spent shale increased the EC e of the shale to over 21 mmhos/cm. Leached and unleached spent shale was fertilized with N at rates of 0, 28, and 56 kg/ha and P at rates of 0, 24.4, and 48.8 kg/ha. The total biomass for any fertilizer treatment was <1 g. We conclude that covering shale disposal piles with topsoil may improve the site for successful invasion by a colonizing species such as cheatgrass.