Delayed seeding and nutrient amendment seed enhancement technology: potential to improve sagebrush establishment?

Abstract

The sagebrush steppe provides vital habitat across the western United States, but its range is declining. Wyoming big sagebrush (Artemesia tridentata Nutt. spp. wyomingensis Beetle & Young) is difficult to establish on restoration and reclamation sites, with low seedling survival due to drought, competition, and limited available nutrients. Incorporating seeds into seed enhancement technologies (SET) has potential to overcome barriers to establishment. Here, we tested the effects of a high phosphorus nutrient amendment using three application techniques (dust over bare seed, dispersed seed pellets, and clustered seed pellets) versus bare seed on sagebrush establishment on 5‐, 1‐, and 0‐year‐old mine reclamation sites. Regardless of seed technology, emergence was highest in the year 5 site, but survival was lowest, likely due to competition from established plants. Survival and growth were highest in the year 0 site, but emergence was lowest, likely due to poor soil stability. The year 1 site, where soil was stable and competition was low, produced the greatest number of surviving seedlings. Across all times since reclamation, pellets reduced emergence compared to dust and bare seed treatments. There was no clear evidence of any benefit of the SETs. These results highlight the challenges of delivering nutrient amendments in SETs and unresolved questions about the effectiveness of the amendment tested here. Seeding sagebrush 1 year after reclamation may be an additional way to improve restoration and reclamation success for this foundation species.