|
|
||||||||
ABSTRACT
Soil development in the Willamette Valley is related to a sequence of seven extensive geomorphic surfaces ranging in age from postsettlement to middle Pleistocene. The surfaces were mapped on high-altitude aerial photographs for an area about 7,800 km2. The oldest surface associated with the present drainage system is at least 5,250-years-old and may be as old as 34,410 years. One soil series considered representative of each geomorphic surface was chosen to illustrate soil development on successively older surfaces. Soils on the most recent surfaces have developed only A1 horizons containing about 4% organic matter. Soils develop cambic B horizons within 550 years, whereas Bt horizons are formed within a period of 5,250 years. Base saturation progressively decreases from 100% in the Haploxerolls on the younger surfaces to less than 35% in the Haplohumults on the oldest surfaces.
1 Joint contribution Soil Conservation Service, USDA, and the Oregon Agr. Exp. Sta., Corvallis, 97331. Technical Paper no. 2784, Oregon Agr. Exp. Sta. Presented before Div. S-5, Soil Science Society of America, Nov. 10, 1969, at Detroit, Mich.
2 Research Soil Scientist, Areal Geologist, and State Soil Correlator, respectively, Soil Conservation Service. C. A. Balster is presently Research Petroleum Geologist, Montana Bureau of Mines and Geology, Billings, Mont.
Received for publication December 15, 1969. Accepted for publication February 18, 1970.
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| The SCI Journals | Agronomy Journal | Crop Science | |||
| Journal of Natural Resources and Life Sciences Education |
Vadose Zone Journal | ||||
| Journal of Plant Registrations | Journal of Environmental Quality |
The Plant Genome | |||