Get reliable science

Western US rangelands are declining due to catastrophic wildfires associated with weed dominance. Restoration efforts commonly require that native perennial species be reseeded in fall. Seeds are drilled or broadcast from an airplane and fail to establish due to unfavorable moisture and temperature conditions. Failure results in weed dominance and recurrent wildfires. Recent research indicates that seeds planted in fall may germinate; causing seedlings to be subject to mortality from frost over winter. We propose that abscisic acid (ABA), a plant hormone that delays germination, can be applied through seed coating technology to delay seed germination until spring and subsequently prevent winter seedling mortality. We are coating bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) A.Love), bottlebrush squirreltail (Elymus elymoides (Raf.), and blue flax (Linum lewisii (Pursh.) with five different ABA concentrations and testing under five different temperatures. We have found that higher ABA concentrations result in greater germination delay. We will use our extensive set of soil moisture and temperature data to determine if the delay is sufficient to avoid freezing temperatures. This research will guide subsequent field experiments which have the potential to increase seeding success and restore weed-dominated rangelands.