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A comparison of methods for evaluating aggregate stability of mountain soils




Chunkao, Kasem, 1938-, author
Meiman, James R. (James Richard), advisor
Johnson, Donald D., committee member
Terwilliger, Charles, Jr., committee member

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A comparison of three methods -- Middleton dispersion ratio, wet sieving, and waterdrop impact -- of testing aggregate stability was made. Soil samples were selected from 9 sites representing a wide variety of great soil groups in the Colorado Front Range of the Rocky Mountains at elevations ranging from 5,000 to 11,000 feet. Samples of the top of the A and B horizons were taken. A great variation in stability ranking was found by the different methods. The A and B horizons, although quite different from each other, gave similar responses to the different methods. There was a distinct tendency for the stability rankings of the B horizons to vary less than A horizons, with the different methods. The B horizon was more stable than the A horizon for all soils with the wet sieve test whereas with the waterdrop impact method only one soil had the B horizon more stable than the A horizon; the dispersion ratio test did not detect any significant (5% level) differences between the A and B horizons. The dispersion ratio was the least powerful test in terms of defining differences between soils; the use of 2-3 mm soil instead of <2 mm soil increased the distinguishing power somewhat. The waterdrop impact method was the most powerful test in terms of defining differences between soils. The wet sieve method was intermediate between the dispersion ratio and waterdrop impact methods.


Covers not scanned.
Print version deaccessioned 2021.

Rights Access


Soils -- Research


Associated Publications

Meiman, James R. Little South Poudre Watershed and Pingree Park Campus. Colorado State University, College of Forestry and Natural Resources (1971).