Tradeoffs and Challenges in the Development of Prototype Seed Enhancement Technologies for Sagebrush

Restoration of dryland plants from seed often fails or has very low success. Seed enhancement technologies (SETs), such as seed coatings with growth-enhancing amendments, offer potential means to increase early seedling survival and establishment success. Here, we tested the potential for four prototype film-coating SETs and two externally applied nutrient amendments to improve establishment success for Wyoming big sagebrush ( Artemisia tridentata spp. wyomingensis Nutt.). These were tested in the laboratory and at a mine reclamation site in both fresh reclamation (year of) and postreclamation (1 yr after) sites. Film coatings did not inhibit emergence, an improvement from previous trials involving pellets or thicker coating prototypes. However, they also did not improve seedling growth or survival. One externally applied nutrient amendment strongly reduced seedling emergence but enhanced seedling size and field survival, whereas the other had no substantial effects. We conclude that film coatings on these very small seeds did not supply enough amendment to have any effect, whereas higher rates of amendments appear to bring tradeoffs between emergence inhibition and later growth enhancement. Although we tested a limited number of SETs in this study, these results highlight the challenges of using SETs for small-seeded species like sagebrush. We suggest that bet hedging by seeding at different stages of reclamation or multiple years in a row may improve overall outcomes.