Postfire drill-seeding of great basin plants: effects of contrasting drills on seeded and nonseeded species

Authors: OTT, JEFFREY - Us Forest Service (FS); COX, ROBERT - Texas Tech University; SHAW, NANCY - Us Forest Service (FS); Newingham, Beth; GANGULI, AMY - New Mexico State University; PELLANT, MIKE - Bureau Of Land Management; ROUNDY, BRUCE - Brigham Young University - Idaho; EGGETT, DENNIS - Brigham Young University - Idaho

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2016
Publication Date: 6/20/2016
Citation: Ott, J.E., Cox, R.D., Shaw, N., Newingham, B.A., Ganguli, A., Pellant, M., Roundy, B.A., Eggett, D.L. 2016. Postfire drill-seeding of great basin plants: effects of contrasting drills on seeded and nonseeded species. Rangeland Ecology and Management. 69:373-385. https://doi.org/10.1016/j.rama.2016.05.001.
DOI: https://doi.org/10.1016/j.rama.2016.05.001

Interpretive Summary: Post-fire rehabilitation using seed drills are often used in the Great Basin to reduce invasive species and facilitate ecosystem recovery. Conventional drills are most widely used; however, the development of modified drills to accommodate different seed sizes and planting depths are on the rise. An experiment was conducted to test the effectiveness of a conventional and minimum-till drill for seeding native plant mixes following wildfire in Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young) communities. Seeded plant establishment varied by site where the poorest plant establishment was at the lowest precipitation site. Overall, the minimum-till drill increased the establishment of small-seed species; however, the conventional drill was most effective for large-seeded species. Our results illustrate that using one drill type may be prove difficult when trying to plant diverse seed mixes.

Technical Abstract: Objectives of post-fire seeding in the Great Basin include reestablishment of perennial cover, suppression of exotic annual weeds, and increasingly restoration of diverse plant communities. Non-conventional seeding techniques may be required when seeding mixes of grasses, forbs and shrubs containing seeds of different sizes. We conducted an operational-scale experiment to test the effectiveness of two rangeland drills (conventional and minimum-till) for seeding native plant mixes following wildfire in Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young) communities. Both drills were configured to place different sized seeds in alternate rows. We hypothesized that the minimum-till drill’s advanced features would improve establishment compared to the conventional drill. We also hypothesized that the minimum-till drill would cause less damage to residual perennials whereas the conventional drill would have a greater impact on annual weeds. The experiment was replicated at three burned sites and monitored for two years at each site. Seeded plant establishment was lowest at a low precipitation site that became dominated by exotic annuals. Another site had high perennial grass establishment which effectively suppressed exotic annuals, while a third site attained high diversity of seeded species and life forms but became invaded by exotic annuals in plant interspaces. Small-seeded species generally established better with the minimum-till drill equipped with imprinter wheels than the conventional drill with drag-chains. However, large seeded species frequently established better with the conventional drill despite its lack of depth bands and press wheels. Soil disturbance associated with the conventional drill had a negative effect on residual perennials and exotic annuals at some sites. Results indicate that different drill features are advantageous in different ways, but that either of the tested drills, if properly used, can be effective for seeding native plant mixes provided site conditions are otherwise favorable for seedling establishment.