Developing an integrated management decision framework for cheatgrass control in the northeastern region of the sagebrush steppe

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Commodities

• Agronomic: grass (misc. perennial)

Practices

• Education and Training: participatory research
• Pest Management: integrated pest management, weed ecology

Cheatgrass has invaded millions of acres of the sagebrush biome, impacting forage production for cattle and habitat quality for wildlife such as sage-grouse. Restoring highly infested rangeland to a more desired state is impossible. Therefore, areas with moderate and patchy cheatgrass infestations should be prioritized for control to thwart further expansion and rangeland degradation. Much of the northeastern region of the sagebrush steppe (e.g., Montana and Wyoming) falls into this moderate risk category, and producers in this region are concerned that cheatgrass is expanding and want help now, before the problem gets worse.

Our team will field test combinations of strategies to determine which control cheatgrass most effectively and restore desired vegetation. Firstly, the effectiveness of cheatgrass control using targeted grazing, herbicide, and seeding will be tested in different combinations in a producer-initiated, large scale study at three sites. However, restoration seeding is expensive and may be less effective where the desired vegetation is more abundant.  Therefore, in the second highly replicated study we will evaluate the threshold of desired vegetation below which seeding after herbicide application is beneficial to decrease cheatgrass and increase desired vegetation. Thirdly, the effectiveness of cheatgrass control will be tested using innovative, non-herbicide approaches (soil micronutrient and two biofumigation techniques —mustard mulch and mustard seed meal) and compared with herbicide. Additionally, we will seed half of each of those treatments.  We will evaluate the cost of all the different control strategies and combinations.

Finally, our research, extension and producer team will use the results of our studies to develop a decision framework for producers. The framework will guide users to the most appropriate combination of management strategies to control cheatgrass and ensure recovery of desired vegetation for their ranch sustainability and livelihood. The project will be performed in southwest Montana and is applicable to the northeastern region of the sagebrush steppe.

We will extend the results of our studies using a range of formats including field days, tailgates, meetings, and workshops, as well as digital social media forums and websites.  The management options in our decision framework will be based on the best management approaches from our studies. However, it will require producers to supply information on the invasion status of cheatgrass and site conditions, in order to guide them to the best management approaches for their ranch. We will use our different outreach events to obtain feedback on the framework from a broad range of producers and land managers to ensure clarity, usefulness, and high rates of adoption.

Concern about cheatgrass is increasing in southwest Montana, where it is a particular problem on south-facing slopes. Our study will be performed on cheatgrass patches established on south-facing, high elevation sagebrush rangeland sites. Different combinations of control strategies will be assessed in a series of studies with the goal of promoting good stewardship of rangelands in the northeastern region of the sagebrush steppe. 

1) Evaluate combinations of targeted grazing, herbicide, and seeding for cheatgrass management and desired species restoration, in a large-scale, rancher-initiated study.

      Assess abundance of (a) cheatgrass, and (b) seeded and all other species, in large treatment plots over three years.

2) Determine a threshold for restoration seeding after herbicide application for cheatgrass control.

      Assess abundance of (a) cheatgrass, and (b) seeded (native perennial grasses and annual forbs) and all other species, across a gradient of native grass cover (0-30%) present at the site prior to treatment, to determine when seeding is most beneficial (e.g. <20 % cover).

 3) Quantify the effectiveness of six control strategies, with and without seeding to control cheatgrass.

      Assess abundance of (a) cheatgrass, and (b) seeded and all other species to six treatments (herbicide, soil micronutrient application, grass mulch, mustard crop mulch, mustard seed meal, and no action), with and without seeding, over two years.

 4) Develop a decision framework to help livestock producers effectively control cheatgrass on their property.

Through objectives 1-3 we will develop effective combinations of strategies to control cheatgrass and improve range quality and productivity. The decision framework will use information on cheatgrass, site conditions, and desired grass cover to help producers select the most appropriate management approaches for their property and resources. The management decision framework will be extended through our outreach and educational activities (see that section) throughout the project period and beyond.