The phenomena known as "phosphorus-induced zinc deficiencies"
are poorly understood. Conclusions drawn from research efforts
designed to identify the mechanism of the phosphorus-zinc interaction
are, in many cases, incompatible. Similarities in the data from
a number of literature reports of "phosphorus-induced zinc deficiencies"
have led to the development of the...
Soils developed on volcanic ash exhibit several unique properties
not commonly observed in soils formed on other geologic
material. Low thermal conductivities, low volumetric heat capacities,
slow transport phenomena, excess macro-drainage and
development of unique suites of clay minerals are some properties
thought to be directly related to the vesicular...
Wheat varieties of differential tolerance to Al were used in a
series of nutrient solution experiments to study the inhibitory effects
of Al on growth and nutrient uptake. The pH and the Al and P concentrations
were rigorously maintained to prevent the confounding
effects of Al and P precipitation and...
The understory vegetation was sampled in eight plant communities
of a Douglas-fir ecosystem to determine the organic matter
production and mineral composition.
Four sample sites were selected in each plant community and
the understory vegetation sampled using the method of quadrats of
successively increasing size. All herbaceous plants were separated...
The objectives of this study were to evaluate and compare the
availability of native and applied P in Central Oregon pumice soils
with that in Willamette valley soils and calcareous soils from Eastern
Oregon. The experimental work to meet these objectives included
laboratory and greenhouse studies.
The removal of P...
Previous studies of pumiceous soils in Oregon indicated that
their physical and chemical properties were strongly related to the
porous nature of the pumice matrix. Soils developed on air-fall
pumice from the eruption of Mt. Mazama (Crater Lake, Oregon) had
low thermal conductivities and low volumetric heat capacities. Values
for...
Representative sites of the Dayton, Woodburn, Jory, Quillayute, Astoria, Willamette, Walla Walla, Deschutes, Laki and Owyhee soil series were investigated for seasonal changes in exchangeable potassium in air dry samples. No consistent seasonal variations were found which could be attributed to wetting and drying in the field. Cropping reduced the...