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...
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...
Heat and water vapor flow in summer-fallowed fields in the
Pacific Northwest may significantly affect the position and supply of
water for germination of fall sown crops. New tillage tools and
drill openers used in reduced tillage systems leave a trashy, residue covered surface in contrast to the traditional bare...
Soil water content and water potential are two important parameters in
determining the status of water in the soil. Improvement in the ability to measure these
parameters by way of increased speed, accuracy, resolution, imaging volume, ease of
automation, as well as reduced calibration requirements and reduced soil disturbance
would...
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...
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...
Irrigated agriculture constitutes the greatest consumptive water use globally, so that irrigation efficiency measures are an important part of global efforts to best utilize this limited resource. However, greater irrigation efficiency must be achieved while simultaneously maintaining or increasing crop yields and farming profitability. Incremental water use decisions are made...
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...
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...
Explica el uso de los sensores matriciales granulares para la medición de la tensión de humedad del suelo. Explica cómo instalar estos sensores y cómo usar los datos registrados para la programación del riego. (Discusses the use of granular matrix sensors (GMS) for monitoring soil moisture content . Explains how...
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.
Una de las herramientas más eficaces utilizadas por el Malheur Experiment Station durante las últimas dos décadas es el sensor matricial granular (o GMS por sus siglas en inglés), el cual mide la humedad del suelo. El sensor tiene sólo 7,5 cm de largo, y normalmente se entierra verticalmente en...
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...
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...
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...
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...
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...
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....
Seed moisture is a primary factor influencing seed quality during harvesting, storage, and marketing of grass seed. However, the Association of Official Seed Analysts' Rules for Testing Seeds do not contain methods for moisture testing. The oven methods in use by seed testing laboratories in the U.S. are diverse and...
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...
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 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.
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.
The effects of aspect, canopy, elevation, and season both singly
and in combination on soil temperatures at 50 cm depths were
evaluated.
The objectives of the study were (i) to develop a standard procedure
for obtaining soil temperature data adequate to classify soils
at the family and great group levels,...
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...
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...
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...
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...
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 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...
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...
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...
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...
A Langmuir sorption model incorporating a second step of
irreversible absorption was applied to a model soil system. The column
was packed with cellulose triacetate; pulse and step input tests with
3,4-dichlorophenol were performed; the effluent concentration was
measured by electron capture detector gas chromatography and sorption
rate constants were...
Many different models and mechanisms of water imbibition into soil have been described in the literature. Theoretical equations based on those models exist to predict how water will flow in porous media. These models can be useful, but have their weaknesses. Research on imbibition and infiltration into soils has mostly...
The work reported herein was performed under the annual allotment from the Office of Water Resources Research to the Oregon Water Resources Research Institute. Funds were available over a three year period, but due to difficulty in acquiring graduate students, the total time spent on the project was only 21...
There is considerable evidence that the growth and elongation of
plant roots increases linearly or almost linearly with increasing water
contents or decreasing moisture-tension of soil. If this is true it is
difficult to distinguish the effects of different water contents on absorption
phenomena such as water or ion uptake...
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...
This research evaluated the germination and early seedling
development response of two sources of bluebunch wheatgrass (Agropyron
spicatum) to a wide range of environmental conditions. Seeds collected near John Day, Oregon and Secar seed obtained from the Soil
Conservation Service were used in the investigations.
Evaluation of the germination response...
Little is known about biophysical controls on soil respiration in California’s Sierra Nevada oldgrowth, mixed-conifer forests. Using portable and automated soil respiration sampling units, we measured soil respiration rate (SRR) in three dominant patch types: closed canopy (CC), ceanothus-dominated patches (CECO), and open canopy (OC). SRR varied significantly among the...
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
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 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...
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,...
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...
Declared out of print March 2010. 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
Vertisols and other vertic-intergrade soils are found all over the globe, including many agricultural and urban areas. These soils are characterized by their cyclical shrinking and swelling behaviors, where bulk density and porosity distribution both vary as functions of time and/or soil moisture. In turn, alterations in physical soil parameters...
Soil respiration, or the combined CO₂ emissions from roots and soil microorganisms, constitutes one of the largest losses of carbon (C) from terrestrial ecosystems. The major drivers of soil respiration, which include soil moisture, temperature, and substrate quality, have been known for some time. Nevertheless,
correlations between these drivers and...
The Oregon Water Quality Decision Aid (OWQDA) is
a first-tier screening tool that allows you to make a broad
determination of the likelihood that a specific chemical,
when applied to a specific Oregon soil, will move through
the soil and contaminate groundwater. This determination
is called the groundwater vulnerability rating.
In order to determine the physical location of contaminants in soil, two solidified soil
"thin" sections, which preserve the undisturbed structural characteristics of the original
soil, containing weapons-grade plutonium from the Rocky Flats Environmental Test Site
were prepared. Two autoradiographic methods were used in radionuclide mapping:
contact autoradiography using CR-39®...
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.
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 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...
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,...
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...
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