|PHILLIPS, KARMA - Brigham Young University|
Submitted to: Native Plant Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2016
Publication Date: 12/21/2016
Citation: Madsen, M.D., Hulet, A., Phillips, K., Staley, J.L., Davies, K.W., Svejcar, A.J. 2016. Extruded seed pellets: a novel approach to enhancing sagebrush seedling emergence. Native Plant Journal. 17(3):230-243.
Interpretive Summary: Small seeded species are often difficult to plant with standard rangeland drills and are prone to being planted at depths where the seedlings cannot emerge from the soil. Sagebrush seed is an example of one of the smallest seeded species commonly sown on rangeland systems in western North America, with seeds approximately 1 mm in size. We developed and evaluated a potential solution for improving sagebrush emergence by incorporating the seed within an extruded seed pellet. Results indicated that extruded seed pellets can improve seedling emergence by bringing seeds closer to the soil surface and through the swelling action of the pellet creating small voids or conduits for the emerging seedlings to follow out of the soil. This technology opens up the possibility for sagebrush (and potentially other small seeded species) to be drill seeded at deeper soil depths where soil water potential levels are more conducive for seed germination and seedling survival.
Technical Abstract: 1. To sustain North America’s sagebrush biome novel seeding methods are required that can restore degraded landscapes after a disturbance. Seeds need to be planted at an optimal depth where moisture resources are available for seed germination yet not too deep that seedling emergence is impaired. Due to the small size of sagebrush seed, mechanical drill seeding techniques are prone to planting seeds at depths where the seedlings cannot emerge from the soil. 2. We evaluated a potential solution to this problem that incorporates sagebrush seed within an extruded seed pellet that is designed to enhance seedling emergence by bringing seeds closer to the soil surface and, through the swelling action of the pellet creating small voids or conduits for the emerging seedlings to follow. 3. We quantified under controlled laboratory conditions the swelling capacity of the extruded pellet and evaluated how the technology improves seedling emergence and early planting growth of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis), over a range of seeding depths (5, 10, and 15 mm), within silt-loam and sandy-loam soil. 4. Swelling capacity of the pellets in the silt-loam soil was approximately twice that of the sandy-loam soil. At all planting depths pellets improved seedling emergence between 2.3-10.0 fold in the silt-loam soil. In the sandy-loam soil, there was no treatment effect seedling emergence at the 5 and 15 mm depths, but pellets enhanced emergence at the 10 mm depth by 3.1 fold. Particularly in the sandy-loam soil, there is some indication that seedlings produced from the extruded pellets had greater growth than from untreated seed. 5. Synthesis and applications. Results indicate that extruded seed pellet technology may improve sagebrush seeding efforts. This technology opens up the possibility for sagebrush (and potentially other small seeded species) to be drill seeded at deeper soil depths where soil water potential levels are more conducive for seed germination and seedling survival. Future development and field testing is merited.