Two management systems were evaluated in terms of the effects on
cow condition score and body weight changes and calf growth rates. The
management systems evaluated were winter supplementation of energy,
winter creep feeding and delayed weaning. The calves used in this study
were born in September and October of...
The purpose of this study was to evaluate the effects
that free ranging cattle have on water quality in semi-arid
environments. There were three specific objectives:
1) To determine the concentration and distribution of
cattle feces in meadows, riparian zones, and the
associated uplands. 2) To determine the fecal deposition...
More than 200 sites between 500 and 2000 meters elevation
were examined utilizing a reconnaissance sampling technique for a
portion of the eastern slopes of the northern Oregon Cascade Mountains.
Twelve different forested plant communities were described
with data on vegetation, soils and topography. A map of their distribution
and...
Land useable for livestock grazing in the western United States is
diminishing because of spreading municipalities, irrigation developments,
highway construction, recreational demands and withdrawals.
Concurrently, the demand for livestock and livestock products is increasing
because of a rapidly growing population. As a result, production
from the grazing land that remains...
Sulfur-coated urea (SCU), a slow release nitrogen fertilizer,
may be economically competitive with conventional fertilizers, but
little is known of the mechanism of urea release from SCU and the
environmental factors which affect the urea release rate. Objectives
of this thesis were: (1) to determine factors which affect the rate...
A pest management program for Tetranychus urticae Koch in Oregon
peppermint was developed based on studies of sampling, plant phenology,
population dynamics and damage thresholds.
A sample size of 45 leaves provided a confidence level of 90%
and a confidence interval of 50%. Estimation of the sample mean was
based...
The depression of the 1930s had an early effect on the state of Oregon. A
decline in timber and agricultural production resulted in severe unemployment in the
late 1920s. State and local charitable organizations attempted to care for the
unemployed but they did not have the financial resources to do...
Fire severity is hypothesized as an important driver of bird responses to wildfire. For those species that typically respond negatively to increasing severity, Accessibility of high-severity burned forest may be dependent on the proximity of unburned or low-severity burned forest to meet all of the needs of breeding bird species...
Verticicladiella wageneri Kendrick is a vascular wilt
pathogen of conifers, causing a black staining of
colonized sapwood of roots and lower stem. In Douglas-fir,
V. wageneri is intimately associated with insects.
Hylastes nigrinus, Pissodes fasciatus, and Steremnuis
carinatus are commonly associated with diseased hosts,
carry inoculum of V. wageneri in...
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...