Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Agricultural Systems Technology and Education

Committee Chair(s)

Darwin B. Nielsen


Darwin B. Nielsen


John P. Workman


John C. Malachek


Spraying with the chemical herbicide 2,4-D is the most widely used method of controlling big sagebrush. Spraying is very effective in increasing forage production and generally is not poisonous to either man or animals.

Two procedures can be used to calculate the internal rate of return to big sagebrush control: standard and modified discounting. Standard discounting assumes all nonuse costs are incurred in the year of treatment, and the annual income stream is constant throughout the effective life of treatment. Modified discounting correctly assumes the nonuse cost is incurred in the period of deferment, and the income stream does not reach its full potential until after deferment. Thus, modified discounting yields a lower internal rate of return.

Three big sagebrush control methods (spraying, burning, and chaining) offer internal rates of return which are greater than 8 percent (cost of obtaining capital for range improvement).

The most important factors in determining the internal rate of return are the site vigor index and the amount of forage present before treatment. A larger pre-treatment forage yield will give a larger internal rate of return, assuming the vigor index is sufficiently high.

If state and private rangelands infested with big sagebrush are not improved by spraying or other big sagebrush control methods, certain benefits, called opportunity costs, will be foregone. For spraying alone, the expected annual opportunity costs would be $3,048,102.

The economic feasibility of controlling nearly 2 1/2 million acres of state and private rangelands infested with big sagebrush are excellent. The expected annual increase in carrying capacity of 1,830,000 acres of sagebrush rangeland meriting improvement by spraying is 765,855 AUMs. The remaining 623,000 acres meriting control other than by spraying could possibly increase the total number of additional AUMs to over 1 million.