Native seeds incorporated into activated carbon pods applied concurrently with indaziflam: a new strategy for restoring annual-invaded communities?

Reestablishing native perennial vegetation in annual grass-invaded rangelands is critical to restoring ecosystems. Control of exotics, often achieved with preemergent herbicides, is essential for successful restoration of invaded rangelands. Unfortunately, desirable species cannot be seeded simultaneously with preemergent herbicide application due to nontarget damage. To avoid this, seeding is commonly delayed at least 1 year. Delaying seeding increases the likelihood that annual grasses will begin reestablishing and compete with seeded species. Activated carbon (AC) can provide preemergent herbicide protection for seeded species because it adsorbs and deactivates herbicides. Previous studies suggest that a cylindrical herbicide protection pod (HPP), containing AC and seeds, allows desired species to be seeded simultaneously with the application of the preemergent herbicide imazapic. Unfortunately, imazapic is only effective at controlling annual grasses for 1-2 years. Indaziflam is a new preemergent herbicide which exhibits longer soil activity, with which HPPs may be useful. To assess this possibility, we evaluated seeding two native species (Wyoming big sagebrush [Artemisia tridentata Nutt ssp. wyomingensis] and bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) a. Love]), both incorporated into HPPs and as bare seed, at four application rates of indaziflam in a grow room study. HPPs protected seeded species at low, mid, and high rates of indaziflam. The abundance and size of plants was greater in HPPs compared to bare seed treatments. These results suggest that HPPs can be used to seed native grasses and shrubs simultaneously with indaziflam application.