The effectiveness of rangeland and minimum-till seed drills for large-scale restoration of sagebrush wildlands

Background/Question/Methods        Many sagebrush plant communities across western North America are being lost through the related processes of annual plant invasion and increasing wildfire frequency. Post-wildfire restoration of these areas may represent the best chance for interrupting the invasive annual/wildfire cycle and maintaining a diverse, native plant community. With this in mind, wide areas within the Great Basin, managed by the Bureau of Land Management, are routinely drill-seeded after wildfires. However, the scale of community conversion and the diversity of the native communities make restoration technically challenging. We compared the effectiveness of the commonly used rangeland drill, with a newer, minimum-till drill at establishing a diverse mix of native grasses, forbs, and shrubs in post-wildfire restoration experiments near Elko, Nevada. Grasses, shrubs, and forbs were included in the drill mix, and were either drilled into the soil, or “broadcast” onto the soil surface as appropriate. 
Results/Conclusions The drills provided differing emergence patterns, depending on the type of species seeded. Species that were drilled into the soil showed similar emergence between the two drills. Species that were broadcast, however, emerged at higher densities in areas seeded with the minimum-till drill. However, densities of the invasive annual cheatgrass were also higher in areas seeded with the minimum-till drill.  We conclude that higher diversity seed mixes, with species that must be simultaneously drilled and broadcast may be seeded more effectively with the newer, minimum-till drill. Under heavy terrain, or with low-diversity seed mixes, however, the traditional rangeland drill may provide adequate seeding success.