This research examines the community composition of biotic soil crusts at nine sites in central and eastern Oregon, U.S.A. At each site, data were collected in one pair of livestock-grazed and excluded transects. Variables recorded included: cover of biotic soil crusts and vascular plant species, soil surface pH, electrical conductivity,...
Expansion of Juniperus occidentalis into the sagebrush steppe has resulted in significant changes in understory composition. A consequence of increased J. occidentalis dominance may be a depletion of the seed bank. The potential for depletion is problematic because a reduction in the amount of species available from the seed bank...
Western juniper (Juniperus occidentalis) cover has more than doubled within the last century and currently occupies over 9 million acres in the Intermountain West. Encroachment has altered the spatial distribution of soil nutrients and plants in these systems, forming nutrient enriched 'resource islands,' under tree canopies. The purpose of this...
The sagebrush steppe ecosystem of the northern Great Basin is severely degraded and continues to decline due in large part to the invasive, non-native annual grasses Bromus tectorum L. (cheatgrass) and Taeniatherum caput-medusae (L.) Nevski (medusahead). Restoration of invasive-dominated areas is difficult, but can be enhanced by adding a carbon...
Published June 1997. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Juniper is a native species to Oregon and confers ecological benefits to wildlife when it is at savannah and transitional densities. Its range and extent have fluctuated with climatic change, but the current range expansion is unprecedented in its extent. The range expansion has been associated with the degradation of...
Sagebrush steppe ecosystems in the Great Basin have become increasingly threatened by the proliferation of cheatgrass (Bromus tectorum L.), an invasive annual grass. Diverse sagebrush and perennial bunchgrass landscapes can be converted to homogenous cheatgrass grasslands mainly through the effects of fire. Although the consequences of this conversion are well...
Biological plant invasions are diminishing the ecological integrity and function of ecosystems worldwide. A primary example of this is in the Great Basin of the United States, where invasive annual grasses, like cheatgrass (Bromus tectorum L.) and medusahead (Taeniatherum caput-medusae L. Nevski), are dominating many sagebrush-steppe ecosystems. In these invaded...
A study was conducted to investigate the nature of hydroxy
interlayers in the chlorite-like intergrade clays of three Oregon
soils with respect to kind, amount, stability, and conditions of
formation.
The clays of the Hembre, Wren, and Lookout soils, selected to
represent weathering products originating from basaltic materials
under humid,...
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...
Experiments were carried out to study the movement of water and
halide anions in perched water tables or saturated zones in the soil
and upper rock mantle of eight different experimental sites located
on low hills near the western border of the Willamette Valley. At each
site the experimental procedure...
The objective of this study was to estimate the bulk densities and points on the moisture-tension curves and to determine their associated variances for some of the selected mapping units in Central Oregon. These variances will produce informations concerning the precision of the mean and the optimum sampling schemes, for...
This study was undertaken to increase knowledge of opal phytoliths
in plants and soils of Oregon, and thus encourage further use of
phytoliths in future pedologic investigations.
Content of plant opal in needles from ten common Oregon conifer
species ranged from 0.2 to 7.9%. Western larch (Larix occidentalis)
contained the...
Extractable forms of Al and Fe were studied in five soils from
the Coast Range, and in two soils from the Willamette Valley in
Oregon.
Exchangeable Al was determined in a way which permitted a
comparison of three different methods for its determination. Values
for exchangeable Al obtained by the...
A study was conducted to determine the mineralogy and chemical
properties of "Ando-like" western Oregon soils. The samples
were collected from 13 sites which formed mainly from basaltic
rocks, a contact metamorphic rock, sedimentary rocks, and
alluvium derived from sedimentary rock and from volcanic rock. All
samples contained small amounts...
Time of stand establishment is a critical factor affecting
yields of winter wheat and barley in the fallow-crop rotation areas
of the Pacific Northwest. Farmers in this winter-rainfall region
are dependent on residual moisture in the seed zone for germination,
because significant precipitation does not usually occur until
after the...
A diversity in climate, geologic parent material, and soil
characteristics exist in Jackson, Josephine, Coos, and Douglas
Counties of southwest Oregon. Previous field trials and soil testing
results have revealed uncertainties as to the phosphorus (P) status
of the soils in this area. Twenty-four sites from nine agriculturally
significant soil...
Soil samples and soil clods were collected from ten potato fields
in Eastern Oregon. An index of grain size distribution was sought that
would correlate well with compacted soil bulk density. The Hazen
coefficient of uniformity was best related to bulk density. The
limitations of various indices and their relationship...
Published June 1932. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published January 1912. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published February 1898. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published October 1892. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published October 1980. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
I focus on addressing knowledge gaps relating to management of cryptogams in Oregon's public lands in Pseudotsuga menziesii-Tsuga heterophylla forests on the west side of the Cascade Range and dryland steppe in the Cascade Range's rainshadow.
While a great deal of research has illustrated the importance of late-successional forests for...
With agriculture continuing to play an ever-increasing role in our modern economy, more and more attention is being directed toward the hitherto more or less neglected finer points of crop production. In the past it has been the tendency to concentrate research on those factors which most obviously affect agricultural...
Four surface and three subsurface horizons of agriculturally
important Oregon soils were exposed to excessive volumes of anhydrous
ammonia and reequilibrated with the atmosphere for several
time periods prior to extraction with water. The carbon solubilized
was determined by a modified wet combustion technique. Nitrogen
in the soils, extracts, and...
Acidity distribution within any given soil profile is dependent on
mineralogical make-up of the parent material as well as environmental conditions prevalent during the weathering history of the soil.
An experiment was designed to study the distribution pattern of exchange acidity, exchangeable aluminum, exchangeable manganese and
pH of six acid...
Soils representative of several landscape units in the H. J.
Andrews Experimental Forest, Western Cascade Range, were sampled,
analyzed, and tentatively classified. Genetic inferences were
drawn relating soils to landscape position and other factors of soil
formation. Descriptive information and nutrient capital data were
provided to support ecosystem modelling efforts...
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...
Published August 1946. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published January 1973. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
This study consisted of two research projects in the Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh) alliance, the most extensive of the big sagebrush complex in the Intermountain West. In the first project, we intensively sampled 107 relatively undisturbed, late seral Wyoming big sagebrush...
As the management of range lands is intensified or as improvement
activity is increased, a critical need is seen to refine the
understanding of the ecology of these lands. If soil surveys on range
lands are to be meaningful and useful, the relationship between the
fundamental ecological units and the...
Published July 1941. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Covers soil basics such as soil formation, horizons, properties (including textural classes), profiles, site characteristics and evaluation, and the influences of soil characteristics on management decisions. Provides interpretation guides for permeability, water and wind erosion, drainage feasibility, irrigation suitability, most intensive crop, erosion control practice, and septic tank drainfields. Includes...
Published September 1984. A more recent revision exists. Information within this publication may be outdated. Please check for up-to-date titles in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
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...