Abstract
There is a need to develop cost-effective techniques for re-establishing native vegetation on degraded sagebrush (Artemesia spp. L.) steppe ecosystems. In this study, we evaluate the use of solid matrix priming (SMP) and extruded seed pellets as technologies for improving re-vegetation success within the sagebrush steppe for three native bunchgrass species: bluebunch wheatgrass (Pseudoroegneria spicata, PSSP6), Idaho fescue (Festuca idahoensis, FEID), and prairie junegrass (Koeleria macrantha, KOMA). This involved: 1) the formulation of seed priming medium, 2) the incorporation of priming medium and native seed into pellets designed for transportation and subsequent planting for re-vegetation purposes, 3) the determination of optimal seed priming durations at two water potentials (-0.7 & -1.0 MPa), and 4) a comparison of total emergence and time to 10, 25, and 50% emergence for primed seeds vs. non-primed seeds. Primed pelleted treatments for FEID and PSSP6 showed increases in total emergence within the first seven days compared to non-primed pellets. By day seven, FEID and PSSP6 primed pelleted emergence was 8.4–22 and 31.6–58.5 seedlings, and non-primed pellet emergence was 0.2–6.8 and 19.3–31 seedlings (P<0.05). KOMA showed mixed results concerning emergence in the first seven days between primed treatments and non-primed pellets. Further experimentation showed that KOMA total germination, not emergence, was increased by day seven with priming (primed germination = 12.1–16.3 seeds, bare seed germination = 3.1–5.7 seeds; P<0.05). Further comparison between primed treatments and non-primed pellets showed a reduction in time to 10% and 25% emergence (T10, T25) for PSSP6 only (T10: primed emergence = 2.0–4.1 days, non-primed pellet emergence = 4.4–6.1 days; T25: primed emergence = 2.9–5.4 days, non-primed pellet emergence = 6–7.5; P<0.05). Three out of six PSSP6 primed treatments also showed a reduction in time to 50% emergence (T50: primed emergence = 6.9, 7.1, 8.4 days; non-primed pellet emergence = 19.7 days, P<0.05). T10 and T25 was not affected by priming in FEID or KOMA. FEID and KOMA bare seed also never reached T25 within the 21-day study period and so comparisons were not possible. The pellet materials provided an increase in total emergence over 21 days of growth for FEID and KOMA (emergence at day 21: FEID bare seed emergence = 10 seedlings, non-primed pellet emergence = 20 seedlings; KOMA bare seed emergence = 2 seedlings, non-primed pellet emergence = 26 seedlings, P<0.05). PSSP6 emergence results showed little positive effect coming from the pellet materials throughout the 21-day study period. In general, solid matrix priming and extruded seed pellets allowed for an increase in total emergence within the first seven days of growth for FEID, KOMA and PSSP6, and a reduction in T10, T25, and T50 emergence for PSSP6. These increases in emergence within the first seven days of growth may provide an increase in the number of wet-thermal days available for emerged seedlings prior to the onset of adverse environmental conditions (i.e. winter/summer). Implications of these results would be a potential increase in the survival and establishment for a greater percentage of wildland seedings for these three species.