Rangeland Restoration on the Channel Scablands of Eastern Washington

Rangeland Restoration on the Channel Scablands of Eastern Washington

Summary

During year 1, sites on 3 private ranches across a 25 mile transect of the Channel Scablands of Eastern Washington State were prepared, replicated plots established and perennial grasses and forage kochia seeded as described in the first annual report. Three improved varieties of perennial grasses were used including Hycrest II, Vavilov II and Bozoiski II and a native mix of Sherman Big Bluegrass, Western Wheatgrass, Snake River Wheatgrass and Thickspike Wheatgrass. The forage kochia varieties included Immigrant, Sahro and Otovny. The Hycrest II and Vavilov II germinated and established while the Bozoiski II failed for the most part. Of the native mix only Sherman Big Bluegrass established while the response of the other natives was poor. Data collected in year two of the study demonstrated that plots containing Hycrest II, Vavilov II and Sherman Big Bluegrass were successful and these grasses reduced or completely prevented the re-invasion of medusahead, cheatgrass and other weeds. The Bozoiski plot that failed did not prevent re-invasion of the medusahead and cheatgrass and by the end of the second year medusahead had completely taken over the failed and control plots. The forage kochia response was disappointing and only a few plants of the Sahro and Immigrant variety germinated in the replicated plots. However, we determined that there was an herbicide residual in the soils from the initial plot preparation and this undoubtedly reduced the forage kochia response. As a result of the first two years of data three larger (¼ to ½ acre) demonstration plots were established near the replicated plots to provide a larger scale evaluation for upcoming workshops. Using the data from the first year of the study, the seed mix that was selected for these larger plots was a mix of Vavilov II (an improved Siberian Wheatgrass), Sherman Big Bluegrass (Native) and Immigrant forage Kochia (most economical and available forage Kochia variety). These demonstration plots were prepared with minimal soil disturbance and no herbicide application, and seeded in the fall and early winter to demonstrate an economical and practical approach for rangeland improvement to the ranchers, land managers and producers.

Objectives/Performance Targets

Objectives for Year two were completed. 1. Germination rates and seedling establishment were determined in each of the replicated plots and data recorded. The plots were clipped in late summer to collect and compare biomass and forage quality. (completed) 2. Data from years 1 and 2 were analyzed and presented to a stakeholder workshop in the spring of the second year of the project. (completed) Results Year 2. While the results from year 1 and 2 are somewhat preliminary, because data analysis is ongoing, replicated plots clearly demonstrated that improved perennial grasses and forage kochia can be established on the harsh rangelands of the Channel Scablands of eastern Washington. Table 1 demonstrates the germination success and establishment of the grasses during the first and second years of the study. The best performing grasses were Hycrest II, Vavilov II and the native mix with Bozoisky showing poor germination and establishment. In the native mix Sherman Big Bluegrass was the only native with a positive response. The weeds included cheat grass, medusahead and any other non target grass or forb species. Even at this early stage of the project one can see that the lack of re-invasion of the weeds was correlated with the positive response in the grass plots.

The forage Kochia response was poor in the replicated plots. We believe this poor response was from residual herbicide in the soils incident to the preparation phase of the project. However, a few Immigrant and Sahro plants did germinate but were too small to include in the 2nd year assessment. Typically forage kochia requires 2-3 years before establishment can be adequately assessed. There were other seedings of forage kochia in the area where no herbicide was used and the germination response was excellent.

Accomplishments/Milestones

All milestones and objectives for the first two years have been accomplished. Germination and establishment data shown in Table 1 followed by the biomass data in Table 2 clearly demonstrate the potential to improve rangeland conditions in the harsh environment of the Channel Scablands of Eastern Washington. However, much more data and close evaluation will be required to determine the long term success of these improved grasses to persist in this harsh environment and prevent re-invasion of the weeds. Grazing of the replicated plots and large demonstration plots will be done in the fall of year three to evaluate grazing stress on these grasses.

Impacts and Contributions/Outcomes

Medusahead invasion of the Channel Scablands has reached a critical point. Rangeland production and quality have declined significantly over the last 50 years or so in this region. One rancher provided us with data that showed his stocking rate throughout his ranch had dropped by more than 50% since 1990 and he attributes that totally to the invasion of medusahead. During the last 50 years Cheatgrass became the predominant annual grass, and while ranchers were concerned about this and the frequent wildfire cycles that came with it, cattle would utilize cheatgrass providing at least a maintenance diet. However, with the more recent invasion by medusahead and because of the heavy utilization of cheatgrass, medusahead is crowding out the cheatgrass and is rapidly taking over the region. This invasion has degraded the rangelands, reduced wildlife and small mammal habitat, caused pollinators to leave and continues to impact the wildfire cycles.

Figures for Annual Report 2015

Conclusion:

While it is difficult to make any prediction or determine the long term impact of these seeding trials after only two years of information, the early data is very promising.  The reduction in the re-invasion of medusahead into the successful plots (Figure 1) demonstrates the potential to turn back this invading annual and utilize new and improved perennial grasses and forage kochia to improve rangeland conditions.  Furthermore, the biomass data (Table 2) and feed value of the forage kochia (10-12% protein) has the potential to provide a winter forage source and also to provide an alternative protein source when grasses have matured and lost relative feed value.  The strong stakeholder support in this region (Figure 2) is indicative of the scope of the problem and the level of interest created by this research.  The demonstration plots (Figures 3 and 4) are of particular interest to the stakeholders and were established with this purpose in mind.  This allows producers and land managers to observe on a larger scale the economic feasibility and potential for rangeland improvement.  These larger plots are also intended to provide the research information and technology transfer to transition from the published research provided by the replicated plots to the ranch scale applications and improvements. 

Collaborators: