A study was conducted to evaluate the properties of soils in
the fog belt area of the Oregon Coast Range. Soils in the study
were chosen to include only those belonging to Andepts or to andic
subgroups. Samples were collected from eleven sites that were
formed mostly from colluvial deposits of basaltic rocks, sedimentary
rocks, and alluvium derived from volcanic and sedimentary rocks.
The soils studied were characterized chemically and physically, and
the mineralogy of the very fine sand and clay size fractions was
determined. The eleven soils were classified on the assumption that
Andisol is added in the Soil Taxonomy as the 11th order.
Based on the low degree of profile differentiation shown by
profile morphology, it was concluded that all of the soils studied
are in an early stage of development. The soil structure is mostly
granular in the surface and fine subangular blocky in the subsoil.
Field texture and laboratory analyses indicate low percentage clay
compared to silt throughout the profiles. Surface layers are mostly
dark colored.
All the soils have low bulk density, high water holding capacity
at high suction (15 bar), high CEC, high organic carbon, high pH
in NaF, high variable charge, and high phosphorus retention -all of
which indicate a high proportion of amorphous materials in the clay
fraction.
Based on the mineralogy of the very fine sand fraction and
field site observations, it was concluded that basaltic and volcaniclastic
rocks were the major sources of the parent materials that
have weathered to produce a dominance of amorphous materials in the
soils studied.
Chloritic intergrade dominates the crystalline clay size components
of all the soils with minor amounts of smectite, mica, gibbsite,
chlorite, halloysite, and kaolinite.
It was concluded that three out of the eleven soils studied,
have chemical characteristics of spodic horizons based on the amount
of extractable Fe and Al measured, These soils were classified as
Troporthods.
Eight of the eleven soils were provisionally classified as
Andisols. Seven of the eight Andisols were placed in the subgroup
Typic Haplotropands and one under the subgroup Typic Haploborand. / Graduation date: 1983
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37170 |
| Date | 20 August 1982 |
| Creators | Badayos, Rodrigo Briones |
| Contributors | Simonson, Gerald H. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
Page generated in 0.0021 seconds