Pinedale Field Evaluation Plantings

The second year of data is in for the Shell Cooperative Field Evaluation Plantings (FEP) approximately 35 miles south of Pinedale. The trial consists of 72 entries in a replicated, precision-planted plot and to two different seed mixes, both broadcast and drill seeded, adjacent to the replicated plots on an oil and gas well-pad in need of reclamation. The site is contained inside an antelope-proof woven wire fence. The plots were seeded in the fall of 2005. Similar to 2006, temperatures have been slightly above normal and precipitation 50-70% of normal in The area of the state. Key precipitation events occurred on April 23 (0.19 in.), May 5-6 (0.29 in.), and May 21 (0.58 in.), however, total precipitation for the 2007 water year totaled a discouraging 5.15 inches. Despite continued drought conditions, several entries in the replicated plots continue to show impressive results. The top performers, as shown below, were 9 grasses, 2 forbs, and 2 shrubs, with ‘Wytana’ fourwing saltbush achieving a shooping 7 inches of annual growth. Two other shrubs, Open Range and Northern Cold Desert winterfat, were better than the remaining 12 entries. Three other forbs--‘Appar’ blue flax, Old Works fuzzytongue penstemon, and Richfield Eaton’s penstemon--showed impressive establishment at greater than 0.5 plants/lin.ft.

The seed mixtures showed some interesting results as indicated below. While the Bridger Mix slightly improved, there was a decline in the second year for the Shell Mix. In addition, the broadcast plots appear to be more successful than the drilled. The hydro-seeding was determined to be a failure in 2006 and was reseeded, but once again appears to have failed. The plot is located on a site with more slope than the other sites and may not necessarily be directly comparable to the other plots.

The Questar Cooperative FEP was successfully seeded in the fall of 2006. The trial is located approximately 10 miles south of Pinedale on an oil and gas site in need of reclamation. It consists of 25 shrub species precision-planted in replicated plots, along with five bluebunch wheatgrass entries broadcast-seeded adjacent to the shrub plots. The site is contained inside an 8-foot high, deer-proof fence, since it resides within crucial mule deer winter range. Seedbed conditions were excellent, and all who helped with the seeding were hopeful of successful emergence to reward their diligent efforts on the coldest, windiest day of the fall (Larry Holzworth arranged the planting date!). Spring monitoring showed traces of initial emergence from Gardner’s saltbush, chokecherry, curl-leaf and true mountain mahogany, Prospector common snowberry, Open Range and Northern Cold Desert winterfat, Snake River fourwing saltbush, 9087673 western snowberry, and ‘Maybell’ antelope bitterbrush. The second accession of bitterbrush, 9087668, had a high level of emergence in all four replicated plots. All bluebunch wheatgrass plots showed an initial level of emergence with Goldar appearing to show a slight advantage over the other entries.

There had been considerable predation on the bitterbrush by rodents in addition to an aggressive Russian thistle infestation. Very little of the initial bluebunch wheatgrass could be found in the fall. For more information, contact Karen J. Clause, Rangeland Management Specialist, in Pinedale; or Susan Winslow, Agronomist, at the Bridger Plant Materials Center.

By Karen J. Clause, Rangeland Management Specialist.

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Last Modified: 08/21/2008