Demonstration of Leafy Spurge Management Using Sheep Grazing in a Leafy Spurge Barrier Zone

Demonstration of Leafy Spurge Management Using Sheep Grazing in a Leafy Spurge Barrier Zone

Summary

Producers in the tri-county area of Prairie, Fallon, and Wibaux counties in southeastern Montana have implemented a three-tiered management approach to more effectively contain and a prevent the spread of leafy spurge to uninfested rangeland. The first management tier is the Weed Management Area (WMA) at the center of a large leafy spurge infestation (more than 2,500 acres). Biological control is the primary control method in this WMA. To stop the spread, a cooperative barrier zone surrounds the WMA. More intensive leafy spurge management was implemented within this zone. This WSARE project has allowed Log Cabin Ranch to be become a barrier zone demonstration site where more intensive leafy spurge management techniques have been demonstrated and implemented to contain and reduce the spread of leafy spurge in this area. The third management tier is the Weed Prevention Area where early intervention management efforts protect the WPA from weed spread. The knowledge gained from this management approach was shared with area producers through a series of annual field tours.

Objectives/Performance Targets

The first objective of this project was to implement a leafy spurge sheep grazing project in the barrier zone. The targeted grazing time was June, prior to leafy spurge seed set, on heavier infestations along Cabin Creek. Utilization plots will be used to monitor the grazing project.

The second objective was to control 100 acres of smaller satellite infestations of leafy spurge with herbicide on Log Cabin Ranch.

The third objective was to share information on leafy spurge management techniques with 50 area ranchers.

Accomplishments/Milestones

We unfortunately were not successful at securing a sheep herder to graze leafy spurge on Log Cabin Ranch. The sheep owner/herder we had an agreement with was not able to graze his sheep on the project due to the high amount of leafy spurge he was committed to graze prior to our project. We explored other options for hiring a herder and obtaining sheep from other sources. We did not find any alternatives that were economically or practically feasible for this situation. We have been successful, however, in establishing monitoring plots to give us baseline data on weed density and plant composition in the Cabin Creek area.

We have treated and monitored 80 acres of satellite leafy spurge infestations to date using picloram on Log Cabin Ranch. Monitoring and treatment was done by Clifford Householder and the Prairie County Weed District. The Prairie County Weed District hired an additional seasonal employee to help meet the need for more intensive spraying in the Cabin Creek area in 2006 and 2007.

Three field tours of the demonstration site have been conducted since 2005, attended by 170 producers from 3 counties. Tour participants visited grazing monitoring plots where Montana Sheep Institute staff discussed timing and duration of sheep grazing and anticipated results. USDA-ARS Fort Keogh Range and Livestock Research Laboratory scientists discussed a leafy spurge clipping study that is intended to simulate the effects of grazing timing. Participants also heard a testimonial from another rancher who has combined sheep and cattle grazing to manage weeds. Additional tour topics included biological control of leafy spurge using flea beetles, noxious weed identification, range management, herbicide use, noxious weed prevention, and proper sprayer calibration.

Impacts and Contributions/Outcomes

The Montana Sheep institute has helped establish monitoring plots in within the intended sheep grazing area. At the end of June 2005, Plot 001 consisted of 26% leafy spurge, 63% perennial grass, and 11% forbs. At the end of May 2006, Plot 001 consisted of 53% leafy spurge, 46% perennial grass, and 1% forbs. A second plot was also established in 2006. Plot 002 consisted of 24% leafy spurge, 54% perennial grass, 9% annual grass, and 13% forbs. These data show how much leafy spurge growth takes place between May and June, reinforcing the importance of early grazing of leafy spurge. Plot data are enclosed with this report.

Approximately 80 acres of satellite infestations remained controlled with herbicide on Log Cabin Ranch. Other barrier zone producers treated 34 acres of leafy spurge in 2005, increasing the amount to 73 acres in 2006. 23 acres of leafy spurge also were treated in the WMA. In 2007, 55 acres of leafy spurge were treated in the barrier zone. This is reflective of the more intensive management that took place in the barrier zone management tier.

120 producers gained knowledge on using grazing to manage leafy spurge, range management, herbicide use, biological control of leafy spurge using flea beetles, noxious weed identification, noxious weed prevention, and proper sprayer calibration.

Three additional producers have indicated an interest in using sheep to graze leafy spurge. One of those producers is in the WMA and has also begun to implement some herbicide control in addition to the already present biological control. The Prairie County Weed Board is exploring ways to offer incentives for grazing noxious weeds. The producers in the WPA have organized their efforts to complement those in the barrier zone by hiring a range rider to scout for and eradicate new infestations in the WPA.

Producers recognized the long-term sustainability of using grazing as a tool to control leafy spurge. Producers also acknowledge that the need for a herder is a greater obstacle than locating sheep. In short, producers are willing to allow sheep to graze on their property, but are not necessarily willing to own and manage the sheep on their own.

Outreach:

Tri-County Leafy Spurge Tour, July 28, 2005
Location: Log Cabin Ranch, Chris Keltner Ranch, and Steve Thoeny Ranch
Participants: 50

Tri-County Leafy Spurge Tour, July 24, 2006
Location: Log Cabin Ranch, Chris Keltner Ranch, and Tundby Ranch
Participants: 70

Tri-County Leafy Spurge Tour, July 24, 2007
Location: Log Cabin Ranch, Chris Keltner Ranch, and Steve Thoeny Ranch
Participants: 50

Recommendations:

The Montana Sheep Institute already has convincing data of the benefits of grazing noxious weeds. The challenge in grazing projects is the logistics. We would recommend that several approaches to grazing be considered such as hiring a herder, fencing, water development, and sheep/goat ownership by the producer.

Collaborators: