B and C horizon samples from twenty four selected profiles along
a north-south transect in the Willamette Valley were examined for
possible correlation between shrinkage properties and kind of clay
minerals present.
Observations of linear shrinkage, weight loss from a condition
of maximum plasticity, and changing character of X-ray diffraction...
Water conservation and water quality are rapidly increasing in importance in all areas of the world. The ability to accurately measure soil water content and salinity, over a wide variety of conditions, is key to meeting this need. A set of forward prediction models and waveform interpretation algorithms to extract...
Sandy soils are among the least productive soils because of their inability to
store adequate water for plant growth. Their high percolation rate not only allows
water to move quickly beyond the root zone, but also washes nutrients below the reach
of plant roots. High evaporation occurs from the soil...
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...
Measurement of plant moisture stress of 1-2 m understory conifers
was made in "reference stands" on the H. J. Andrews Experimental
Forest in 1970-1972. Maximum stress each year (measured between midnight
and dawn) is closely correlated with the position of each community
along one axis of an ordination of the...
Soft white winter wheat is grown in western Oregon and requires a spring application of nitrogen (N) fertilizer for optimum production. Determining the amount of N to apply has been a challenge for growers. Wheat obtains N from two sources: soil and fertilizer. Both available and mineralizable N can be...
Soft white winter wheat grown in western Oregon requires a spring application of nitrogen (N) fertilizer for optimum production. Determining the amount of N to apply has been a challenge for growers because wheat is produced in numerous rotations that provide varying amounts of N to the wheat crop. Inadequate...
The over-arching theme of this work is that soil data affect the performance and realism of vegetation models with particular focus on their ability to predict or explain disturbances such as fire or disease. We tested the sensitivity of the Excel version of the 3-PG model to soil properties and...
Seed moisture content is the most reliable indicator of seed maturity and harvest timing in grass seed crops. There are two significant times during harvest that knowledge of seed moisture is critical: at swathing and at combining. Swathing within the correct range of seed moisture content will maximize seed yield...
This study presents the theoretical background necessary to model the bearing capacity of shallow and deep foundations in partially saturated soils. The conventional bearing capacity equations for shallow and deep foundations and the 𝛽-method for deep foundation side resistance have been modified to include the effects of matric suction and...
Soil moisture in a crop's root zone must be regularly
monitored to accurately predict crop water requirements.
Most irrigation scheduling services currently
use the neutron probe to monitor soil moisture. Unfortunately,
there is a degree of variability associated
with use of the neutron probe creating uncertainty in
measurements of soil...
As ornamental container nurseries face diminishing water allocations, many are looking to automated irrigation solutions to increase their water application efficiency. This thesis presents the findings of a study conducted at a commercial container nursery to determine 1) whether a capacitance or load cell sensor was better suited for monitoring...
Several investigators have recently called attention to the
fact that the flux equation for water movement in unsaturated soils
may not be an appropriate mathematical model for the development
of the theory of unsaturated flow phenomena.
An analytical theory is developed for the purpose of testing
the validity of the...
Relationships between soil-water stress and plant-moisture
stress were studied with respect to soil classification and cambial
activity in Douglas-fir.
The study sites were forested with Douglas-fir and located in
McDonald Forest and near Marys Peak in the Oregon Coast Range.
Soil-water depletion was followed by the use of gypsum blocks...
Published March 1944. 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
Soils are the largest terrestrial pool of carbon, therefore it is critical to understand
what controls soil carbon efflux to the atmosphere in light of current climate uncertainty.
The primary efflux of carbon from soil is soil respiration which is typically categorized
into autotrophic and heterotrophic respiration. These two components...
Vegetation patterns and species distributions are strongly linked to soil moisture regimes, and populations within a species from contrasting climatic regimes could exhibit differences in the degree to which certain functional traits related to establishment are expressed. Tree seedling survival is crucial for forest regeneration, and thus may be a...
A growth chamber experiment was conducted to determine the
rate of S-urea mineralization and effect of S-urea on the yield of
ryegrass (Lolium multiflorum) grown in Steiwer soil as influenced
by soil temperature (60, 75, and 90° F) and soil moisture stress
(0. 10, 0.35, and 2.50 bars). Plant yield,...
A special apparatus was developed in which the soil moisture
levels of several soil cells could be maintained independently by
various osmotic solutions at a selected temperature. The effect of
four soil moisture suctions and four soil temperatures on the rates
of transpiration, photosynthesis and respiration of monterey pine
seedlings...
The role of moisture stress in seedling physiology and establishment
was studied in both the field environment and laboratory
experiments. Plant moisture stress was measured using the pressure
chamber technique. This technique was modified and tested using a
fascicle of pine needles as a sample, an improvement which allows the...
This report is one of a series issued in cooperation with the Army-Navy-Civil Committee on Aircraft Design Criteria under the supervision of the Aeronautical Board.
A Study conducted at The Island, Lake Billy Chinook, in Central Oregon, examined
differences in the pattern of soil properties between a sagebrush-grass and a juniper-sagebrush-grass community. Juniper invasion is linked with the desertification
process in which the sagebrush shrubs and perennial grasses decline. Patterns in soil
nutrients and other...
Stevia (Stevia rebaudiana) is a perennial herbaceous plant native to Paraguay and used traditionally by the native Guarani peoples for centuries to sweeten medicinal teas. Stevia has only been commercially cultivated over the past 50 years and cultural practice information suitable for implementation by growers is limited. Currently stevia’s commercial...
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...
Published September 1960. 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
The semi-arid dryland wheat-producing areas of the Pacific Northwest are characterized by cool, moist winters and dry, hot summers. The amount of annual precipitation is generally quite variable and inadequate for annual cropping. Where soil depth is adequate, the predominant loessal soils generally supply sufficient moisture for small grain production...
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...
Many miles of roads are built in the Pacific Northwest Forests to provide access for logging and fire protection. Logging roads often cross steep mountainous terrain. Logging roads and the associated cut and fill slopes represent a discontinuity in the natural stress state in the soil mantle. These conditions result...
The Calapooia River, a major tributary of the Willamette River in western Oregon, is a watershed typical of many found in the Willamette Basin. Public and private forested lands occur in the steep Upper Zone of the watershed, mixed forest and agriculture lands are found in the Middle Zone, and...
Forest soils contain a substantial portion of global terrestrial carbon stores. Forest management can influence the soil carbon pool and how soil organic matter functions. The long-term productivity of forests is an ongoing goal where land managers utilize biomass and timber. A site-specific understanding of intensively managed forests can ensure...
Roughstalk bluegrass (Poa trivialis L.) (RB) is a weed species that increased very quickly in grass seed production fields of the Willamette Valley. The invasion of RB in grass seed crops often occurs in waterlogged soils. In waterlogged areas, RB exhibited better competitiveness and had greater population densities than other...
Often low intake rate soils need special consideration when
applying water during an irrigation. Surface flooding for extended
periods may cause adverse crop growth conditions. Properly
designed sprinkler systems often eliminate irrigation problems,
because the application rate and quantity of water applied can be
readily controlled.
Research workers who have...
The human health effects of acute exposure to high levels of ionizing radiation are well understood; however, when these irradiations occur at low levels, there is controversy as to their potential health threat (BEIR V, 1990). For individuals living in areas where the level of naturally occurring background radiation is...
A proposed state-and-transition model (STM) for the Deep Sand Savannah ecological site in central New Mexico was developed using historical data and expert knowledge. This STM was tested utilizing data from short and long term one-seed juniper (Juniperus monosperma (Engelm.) Sarg.) control experiments initiated in 1981 and 1985. Utilizing data...
The application of the widely used Penrnan-Monteith evapotranspiration equation to hybrid poplar trees is impossible without a valid surface resistance. The increase in applications of drip-irrigated hybrid poplar trees for wood chip stock and veneer production, as well as bioremediation, constitutes a need for estimating the evapotranspiration of these trees....
The effect of soil temperature and plant water stress on nitrogen
uptake, growth rate and transpiration rate of wheat (Triticum aestivum
VILL. , Host) seedlings was studied. A special apparatus for the control
of plant water stress and root temperature was used.
Leaf area was measured by the air flow...
Dry land agriculture using summer fallow is a common crop production
practice in the Columbia Plateau region of eastern Oregon. Farmed-over level
terraces are used to control surface water runoff and soil erosion. More than
70 percent of the average annual precipitation around Pendleton, Oregon (350 -
400 mm) falls...
This publication focuses on how to design a soil nutrient monitoring strategy that fits today’s requirements for record keeping and increased accuracy in managing nitrogen (N), phosphorus (P), and other nutrients. We advocate the use of management units or zones for soil testing and nutrient application. To measure a real...
This report is one of a series issued in cooperation with the Army-Navy-Civil Committee on Aircraft Design Criteria under the supervision of the Aeronautical Board.
Safety concerns at the Hanford Reservation require a way to measure the
moisture content of material contained in the high level radioactive waste tanks. The
freezing of material next to a probe was proposed by scientists at Pacific Northwest
Laboratories (PNL) as one approach to solve this problem. It was...
One of many important physical properties that must be known
to understand transport phenomena in soils is pore size distribution.
Presently the pore size distributions of soils are most commonly
obtained from soil water characteristic curves. The soil water characteristic
curves are usually obtained by the pressure plate technique.
It...
Rangelands span over 50% of the globe and approximately 70% of the United States. Although livestock production is an important use of rangelands, the benefits of rangelands are highly diverse. Humans find intrinsic value in protecting these unique and variable landscapes for wildlife, vegetation, and recreation enthusiasts. Woodland plant encroachment...
Under adverse soil moisture conditions a critical water stress
or water potential develops in the plant and productivity is reduced,
or in extreme cases, terminated. Research to determine the soil
moisture status for maximum production of specific crops has been
conducted for decades. The results have done much to increase...
Leaf elongation is a major indicator of plant growth. It is
controlled by complex interactions of many factors including light
intensity, photoperiod, water availability, atmospheric conditions,
and plant water stress. In this study, the response of leaf elongation
to length of photoperiod and to plant water stress as indicated by...
One of the most important tools we have been using at the Malheur Agricultural Experiment Station over the past two decades is the granular matrix sensor (GMS, Watermark Soil Moisture Sensor, Irrometer Co., Riverside, CA), which measures soil moisture. It is only about 3 inches long and normally is buried...
This publication discusses the use of granular matrix sensors (GMS) for monitoring soil moisture content. It explains how to install GMS and use the recorded data for irrigation scheduling.
Published August 1914. 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
Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) ranging
from 9.6 to 14.3 inches diameter breast height were treated with
the organic arsenicals, monosodium methanearsonate (MSMA) and
cacodylic acid. Treatments were applied at monthly intervals from
February, 1967 to October, 1968, to ten to 25 trees each month.
Treated trees were sampled in...
Previous studies have shown loss of ethofumesate activity when
the herbicide was applied to dry soil (2% w/w moisture content) in
both field and greenhouse studies, even when rainfall or irrigation
was received within a few days. Laboratory studies were conducted to
determine the mechanism for this activity loss. Dry...
The links between forests, streamflow, and climate are poorly understood. Despite hundreds of studies over the past 60 years, fundamental questions of forests' effects on the hydrologic cycle remain unanswered. The hydrological cycle involves mutually-dependent biological and physical processes that operate at multiple scales of time and space, and this...
In previous research, bromacil gave good performance when
it was applied in early fall with fairly dry soil conditions and before
the fall germinating weeds had started growth. On the other hand,
if bromacil was applied in late November, December, or January
on nearly saturated soil with weeds that had...
The use of cover crops in young vineyards is not widely accepted in the Pacific Northwest due to concerns of water and nutrient competition between the cover crop and vines. The last 2 years of a 4-year study started in 2009 are reported here. The study evaluated the use of...
Achieving and maintaining sustainability in irrigated agriculture production in the era of rapidly increasing stress on our natural resources require, among other essential actions, optimum control and management of the applied water. Thus, a significant upgrade of the currently available soil water monitoring technologies is needed. The primary goal of...
The work reported herein constitutes a final report for a project funded by the U.S. Department of Interior, Office of Water Resources and Technology, Grant No. 14-31-0001-4218.
The effect of moisture stress and nutrients on the rate of growth
of wheat (Triticum aestivum L. Var. Gaines) seedlings was studied.
A special apparatus in which the moisture stress of several perlite
cells could be maintained constant by osmotic solutions was used.
Predetermined amounts of nitrogen were added to...
The effect of soil temperature and soil water suction on the rate
of phosphorus uptake and growth rate of wheat (Triticum aestivum
VILL. ,
Host) was studied.
Plants were grown in perlite slabs
separated from an osmotic solution by a semi-permeable membrane.
Measurements were made at temperatures of 10.0, 18.3,...
Published July 1981. 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
Forest soils and topography have long been known to influence forest productivity in complex terrain such as Oregon’s Coast Ranges. Incorporating physical site characteristics into predictions of forest growth and yield, however, has been problematic because of the high spatial variability of soil properties and the challenges associated with representing...
Soil infiltration and wettability measurements during the first year following a broadcast burn in the Siskiyou Mountains of
southwest Oregon, have illustrated the magnitude of the effects of light-to-moderate intensity burning on hydrological soil
properties. A prescribed fire near White Creek in late spring significantly reduced soil infiltration for 4...
Data on soil temperature at two locations and five depths, tensiometer readings, and soil moisture release curves for the soils of Findley Lake are presented in this report.
Soil solution samplers have certain inadequacies that limit their range of
possible applications. Passive Capillary Samplers (PCAPS), which apply suction to the
soil pore-water via a fiber glass wick, have shown promising results in preliminary
experiments in regard to collection efficiency of water and of bromide tracers. The
objectives of...
This study focuses on one widespread characteristic of poor soil quality: hydrophobic soil. Previous research has produced conclusive evidence to show that soil hydrophobicity is affected by soil organic matter (SOM) and soil water content (WC). Hydrophobicity that responds to changes in WC is a unique form of surface hydrophobicity...
Woody biomass transportation costs and market values/costs are strongly correlated with the woody biomass moisture content. Properly managing moisture content can potentially lead to economic and environmental advantages in biomass energy markets. Good management requires accurate moisture content measurements. Therefore, availability of accurate, precise, reliable, and efficient tools to assess...