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Fertilizer bags.

Each of these bags held approximately 450 pounds of urea (fertilizer).

Approximately 30 tons of fertilizer.

Approximately 30 tons of fertilizer was applied to achieve the 40 and 80 pound rates on approximately 468 acres.

Helicopter with “spreader” attached.

Over 100 trips were made with the “spreader” attached to the helicopter to complete the project.

Mesa Mule Deer Winter Habitat Improvement Project

The northern end of the Pinedale Anticline known as the Mesa has been well documented relative to its importance for approximately 3,000 to 5,000 wintering mule deer from the Sublette Mule Deer Herd.

The potential for increasing shrub productivity on winter ranges through fertilization was documented by Len Carpenter in 1975, among others. Carpenter studied sagebrush ranges in Middle Park, Colorado with three study sites located in mule deer winter ranges with elevations from 7,800 to 8,200 feet and average annual precipitation from 11 to 14 inches. Carpenter found that "total herbage and shrub herbage yields significantly increased with increasing levels of nitrogen fertilizer each year. Nitrogen fertilizer did not consistently increase forb and grass yields." In addition, with respect to the herbicide treatment, "the herbicide reduced shrub herbage, total herbage, and forb yields in all years. Grass yields increased in all years on the herbicide treated plots."

On the basis of Carpenter's study and a few others, the Pinedale Anticline Project Office originally proposed to fertilize and treat approximately 800 acres with SPIKE (tebuthiron). This would primarily increase shrub production for mule deer and had the potential to increase herbaceous production to benefit other species. After scoping and further analysis, the scope of the project was reduced and an alternative was selected which included the application of nitrogen on two adjoining sites totaling approximately 468 acres.

The nitrogen application was completed on October 23. Precipitation soon followed which helped the nitrogen penetrate the soil and avoided loss of the product.

Sagebrush leaders and herbaceous production will be closely monitored on an annual basis during the next several years to determine the success of the treatment. Future projects or phases are being considered and identified pending the success of the project based on the monitoring results.

Loading. Spreading of the fertilizer.

The “Bobcat” was used to load the hopper 
or spreader that the helicopter used.


Above illustrates the actual spreading
of the fertilizer.

Last updated: 12-22-2010