Biogeochemical data from four small watersheds in the Silver Creek study area, southwestern Idaho, provide the basis for: 1. An estimate of chemical and erosional denudation rates (CD and ED), 2. an estimate of plagioclase weathering rate, 3. a rational basis for estimating the rate of nutrient supply to soil...
Application of sewage sludge to soils increases the trace metal
content and the organic content of soils. The complexation of indigenous and added metals with organic constituents must be studied to
evaluate metal availability to plants and animals.
The water soluble organic fractions (WSOF) from an agricultural
soil (W), a...
Several crops grown in the Willamette valley of western Oregon
respond to applications of boron fertilizers. The acid, highly-leached
soils of this area are naturally low in plant-available B. Application
of B to the soil annually or at less frequent intervals is currently
recommended, but the fate of applied B...
The lentil strain of pea seedborne mosaic virus, PSbMV-L, was
distinguished from the standard isolates of PSbMV by a natural inoculum
reservoir in lentil seed and by separate resistance genes in Pisum
and Lens. PSbMV-L was intermediate in symptom severity between the
standard and New Zealand isolates of PSbMV.
Seed...
Douglas-fir seedlings were inoculated with different species of
ectomycorrhizae-forming fungi in order to test the concept that
ectomycorrhizae enhance the drought tolerance of seedlings and to
investigate the mechanisms responsible for this effect.
Seedlings were transplanted at age 6 to 8 weeks into pots
containing pasteurized loam soil and inoculated...
About 7,000 years ago two major tephra-falls blanketed the
Pacific Northwest in volcanic ash. These two tephra-falls, identified
as the Llao and climatic tephra-falls, were a part of the eruptive
events that led up to the collapse of Mount Mazama to form Crater Lake
in the southern Oregon Cascades.
The...
The effects of broadcast gypsum on infiltration rates, crusting,
aggregate stability, and runoff and sediment yields were analyzed
during the winter months on three West Oregon soils. The results were
used to evaluate its utility as a management tool to help control
erosion.
An application rate of two metric tons...
The emission of sulfur oxides from anthropogenic sources represents a potential threat to terrestrial ecosystems. Sulfate, the most highly oxidized form of sulfur, is the most common form of inorganic sulfur in most soil environments. The sorption of sulfate may influence the alkalinity of the soil solution and as a...
Lack of stability of soil aggregates for water
movement is a major problem in arid soils due to low
organic matter and higher sodium contents. Soil
amendments for improving stability of structure and
increasing infiltration of water are essential to solve
water management problems in these areas.
Different rates of...
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...
This study was undertaken to determine both the amount and the
spatial variability of sand, silt, clay, and six fractions of coarse
fragments in soils representing harsh sites for reforestation. Particle size data were collected because of their direct relationship to
water holding capacity and the plantability and survivability of...
A microclimatology study was conducted on a high elevation clearcut
near the summit of Mt. Ashland in southwest Oregon to evaluate the effects
of frost on Douglas-fir seedling growth and survival. Frost and low
temperatures cause seedling stress through frost damage, frost desiccation,
increased root resistance, and decreased rates of...
Clay mineral genesis was studied in soils representative of several
different geomorphic surfaces in western Oregon, ranging in age from
Pliocene-early Pleistocene to late Pleistocene. Soil solution studies,
clay mineralogy, and soil raicromorphology were employed to provide
evidence of clay mineral synthesis and interpret soil genesis.
Soils at each study...
Measurements for water retention calculations and physical
characterization were made on skeletal and non-skeletal soils in
southwest Oregon. A new bulk density sampler was designed for the
physical characterization of the steep, skeletal soils commonly
encountered in this area. The new sampler and the techniques
required for the measurement and...
Laboratory incubation studies and field studies with sweet corn
and onions were undertaken to evaluate interactions of lime,
phosphorus (P), and copper (Cu). Eight soils were incubated at a
constant temperature of 21 °C with combinations of band placed
monocalcium phosphate (MCP), ammonium sulfate (AmS), and copper
sulfate pentahydrate (CSPH)...
Freeze/thaw cycles are numerous in agricultural soils of the Pacific Northwest. Potential loss of soil by erosion is high whenever a soil thaws from the surface creating a saturated soil overlying an impermeable frozen layer. Field studies were conducted to investigate the effect of surface residue on soil freezing. Residue...
Intensive cultivation of Walla Walla silt loams (coarse silty,
mixed, mesic, typic Haploxeroll) in eastern Oregon and Washington
during the past 50 years, has decreased internal soil drainage in
the 15 to 40 cm layer. However, no measurements have been made to
determine the causes and corrective management for this...
Soil pore size distribution and water characteristics are important for water storage, water movement, and soil-plant interaction studies. Laboratory determinations of water characteristics and pore size distribution are time consuming and costly. Investigators have proposed many models to predict them from routinely available data. Most of the models are related...
Soils are 3-dimensional bodies that make up natural landscapes.
In addition to the morphological properties used to characterize
soils, soil bodies also have the properties of size and shape. Soil
maps are made in an effort to provide information on the spatial
distribution of different kinds of soils. Soil mappers...
Potash rate and source effects on tuber yield and quality
(hollow heart, size, and processing quality), and nutrient (K, Ca,
Mg, and C1) concentrations in petioles and tubers were evaluated in
three experiments, two in the Columbia Basin in Oregon (McDevitt and
Levy) and one in Central Oregon (Powell Butte)....
Relationships between sagebrush-dominated plant communities and
soil-site characteristics were examined on 372 relatively undisturbed
rangeland sites of the Humboldt National Forest, in northeastern
Nevada. Plant species production data were analyzed by TWINSPAN to
develop a hierarchical, floristic-based community type (C.T.) classification.
Seventeen C.T.s were identified in this analysis and named...
Experiments were conducted to compare differences in P uptake
characteristics between two winter wheat cultivars Stephens and
Yamhill (Triticum aestivum L) as related to root morphologies.
Root length, root surface area and mean root radius were compared.
Plant roots and shoots were separately analyzed for P content.
The cultivars were...
Twelve Sri Lankan Alfisols were characterized for P. Soils
were incubated for three weeks with sufficient P applied
(P2) to elevate soil solution P to 0.2 ug P/g solution as
determined by sorption curves, with 75 percent of P2 (P1),
and without P (P0). For PO treatments, (a) organic P,...
This thesis presents novel findings regarding
symbiotic, physiological, and antigenic characteristics of
representatives from an indigenous soil-borne population
of Rhizobium meliloti. Nodules were sampled from 'Vernal',
'Anchor', and 'Saranac' alfalfa, and the isolates analyzed
serologically. Rhizobium meliloti serogroup 31 was
identified as a dominant nodule occupant, with a greater
and...
The effluent from on-site sewage disposal systems has been
found to be a source of nitrates (NO
₃⁻
) in groundwater. Vegetation
has the ability to remove some of the nitrogen (N) from sewage
effluent as the solution moves through the soil around a disposal
trench, before it reaches groundwater....
A series of field experiments was established in 1978, 1979, and 1980 on Lower Klamath Lake where Mn deficiency of oats had been observed in previous years. The pH of the soils ranged from 7.6 to 8.3 and the organic matter content was between 17 and 19%. The objectives of...
In order to develop three models for use in quantifying the
environmental conditions of reforestation, extensive measurements
required for energy balance calculations were taken for a
reforestation site in southwest Oregon. The models are used to
decrease the number of measurements required to properly evaluate
the potential for heat or...
Distribution and characteristics of soils were determined across
a series of six coastal terraces in Curry Co., Oregon.
Classification of soils and interrelationships of properties were
determined. Soil-landscape relationships were examined and soil
profile development related to relative ages of terraces. Ten pedons
were sampled from five terraces of Pleistocene...
The behavior of six herbicides in soil was studied under controlled laboratory conditions. Sorption of bromacil, chiorotoluron and diuron was assessed by the batch equilibration procedure over a broad range of aqueous phase sorbate concentration. Linear equilibrium sorption constants (K[subscript p]) were slightly higher at 4° C than at 25°...
Complementary methods of strain identification were sought to
delineate the composition of the population of Rhizobium trifolii
found in nodules of Trifolium subterraneum L. when exposed to an
Abiqua silty clay loam (Cumulic Ultic Haploxeroll) containing a
resident population of R. trifolii. Sodium dodecyl sulfate
polyacrylamide gel electrophoresis (SDSPAGE) was...
Nodulation success by two indigenous Rhizobium
trifolii serogroups, 6 and 36, on subterranean clover
(Trifolium subterraneum L.) was affected by the addition
of phosphate to Abiqua soil (Ultic Haploxeroll). To
understand the impact of phosphorus nutrition on the
survival and nodulation characteristics of the two
serogroups, studies were carried out...
Previous research had identified four serogroups of Rhizobium trifolii
indigenous to Abiqua soil (fine, mixed, mesic, Cumulic Ultic Haploxerolls).
Nodulation of subterranean clover (Trifolium, subterraneum L.) by two of the
serogroups, 6 and 36, was influenced by the application of CaC0₃ to the soil.
The studies described in this thesis...
A 2-year field study was conducted on the effects of two sulfur
fertilizers (calcium sulfate or elemental S, 0 or 50 kg S ha⁻¹ yr⁻¹)
on the distribution of sulfur fractions (inorganic sulfate, C-bonded,
ester sulfate, and residual S), arylsulfatase enzyme activity, and
microbial biomass carbon (C) and sulfur (S)...
The purpose of this study was to use computer analysis of soil and rainfall data to predict the possible occurrence of soil erosion in Central Tunisia. Analysis was done with the program OR-NATURE (M.Ungs et al, 1985) . Central Tunisia was subdivided into northern, central, and southern subzones. Data about...
Shallow, rapid soil mass movements are common events and primary sources
of sediment in steep terrain of the Pacific Northwest.
Poorly vegetated debris deposits and scars resulting from landslides
remove land from the productive timber base, and are subject to
continuing erosion. To examine the impact of these events on...