Russian thistle (Salsola spp.) control in California rangelands over five years

Abstract

Russian thistle, also known as tumbleweed (Salsola spp.), is a problematic invasive plant found on natural and working landscapes. On a California rangeland, we tested the singular and interactive treatments of grazing, herbicide and seeding to determine how these approaches might influence Salsola cover across a five year experiment. Total Salsola cover declined by 3% annually during the study. A single spring treatment of chlorsulfuron + 2,4-D followed by glyphosate applied in the fall just prior to seeding, and then 2,4-D the following spring, significantly reduced Salsola cover compared to the untreated control. Seeded forage species cover increased over time and was significantly higher than seeded native species cover five years after seeding. However, the seeding treatment had no effect on Salsola cover. Although grazing did not reduce Salsola cover, due to the beneficial effects of grazing on reducing other non-native species, this study supports the use of an integrated approach of herbicide application, grazing and seeding to achieve management goals on an arid working landscape.