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Liming requirement of selected Willamette Valley soilsPeterson, Paul William 01 September 1971 (has links)
There are two major problems associated with soil acidity and
lime response investigations:
A. Determining how much lime (100% "available" CaCO��� equivalent)
is required to raise a soil pH (or degree of acidity) from its
existing level to a specified level - presumably where need for
lime is eliminated.
B. Determining responses of different crops on different soils to
lime; and defining some chemical measurement of the soil that
will predict the response of a specified crop.
Investigations in this study were limited to the first problem.
Liming characteristics of 45 acid Willamette Valley soils, representing
the major agricultural soil associations, were determined by incubating
the soils with increments of CaCO���. The lime required to
bring the soils to the specified pH levels of 6.8, 6.4 and 6.0 varied
widely within the respective pH levels. Relationships between soils,
however, as determined by the value of the incubation curve slope
(meq. of CaCO��� /100g of soil required to raise soil pH by one unit),
were improved by grouping into related soils. Laboratory measurements
of other soil chemistry parameters were compared with
changes in pH to determine if a satisfactory quick laboratory procedure
could be developed to measure the incubation lime requirement
of soils with different chemical characteristics.
Measurements of soil pH were made by three different methods:
(1) in the supernatant of a 1:2 soil to water suspension; (2) in the
sedimented paste of the 1:2 soil to water suspension; and (3) in the
supernatant of a 1:2 soil to 1 N KCl suspension. Lime requirement
with a buffered solution was measured in limed and unlimed
soils by use of the SMP (Shoemaker, McLean, and Pratt) buffer
method. Soil samples treated with increments of lime were analyzed
for extractable Al and exchange acidity by titration and the unincubated
soils were analyzed for exchange acidity determined by subtracting
exchangeable bases from CEC measured at pH 7. 0 and pH 6. 0.
Results of the correlation analyses showed that the SMP buffer
method should prove useful for predicting the incubation lime requirement.
Correlation coefficients for these two values were .89, .90
and 86, respectively, to reach pH levels of 6.8, 6.4 and 6.0. Soil
pH measurements, extractable Al, and exchange acidity determinations
did not provide as good a basis for determining incubation lime requirements,
Regression equations were calculated for the SMP
buffer/incubation lime requirement relationships.
The purpose of this study was to identify the changes in soil
chemical measurements that take place with application of lime. No
attempt was made to determine whether a crop might respond to an
application of lime on an acid soil. The assumption was made that
yield could be related to specific pH or soil acidity levels that could
be measured in the laboratory. Therefore, the problem was approached
by studying procedures that might determine the application of lime
required to reach a specified pH or soil acidity measurement. It
anticipated that field trials for evaluating lime response will be
carried out in the future to evaluate the usefulness of the SMP buffer
method which showed promise in this regard. / Graduation date: 1972
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Annual cycles of organic matter and phytoplankton attributes in the Columbia and Willamette Rivers, with reference to the Columbia River EstuarySullivan, Barbara Elaine 25 February 1997 (has links)
Graduation date: 1997
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The marine air penetration of the southern Willamette Valley and its effect upon agricultural field firesSielaff, Carl Ogden 28 May 1980 (has links)
This research consists of two related yet distinct
studies: an observational study of the surface character of
the penetration of marine air into the southern Willamette
Valley and a climatological study of the summertime air
masses of northwestern Oregon.
For the observational study, temperature and estimated
wind data were gathered by automobile. Mesoscale analysis
of several cases indicate that the Marine Air Penetration
(MAP) occurs regularly in approximately the same area and
is strongly controlled by the topography. Qualitative
observation and reasoning strongly suggests that the strong
winds and increased stability at the top of the marine layer
have an adverse effect upon agricultural field fires.
Results of the climatological study indicated that the
application of the partial collective method of analysis to
July maximum temperature data from the U.S. Climatological
Network yielded a meaningful air mass climatology for northwestern Oregon. To our knowledge, this is the first time that the partial collective method has been applied to a
region with mountainous areas west of the Rocky Mountains or
to the mesoscale. / Graduation date: 1981
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Geochemical characteristics of iron-manganese nodules in seasonally-saturated soils of the Willamette Valley, OregonSeter, Lisa M. 15 July 1998 (has links)
Graduation date: 1999
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The effects of patch size and isolation on juvenile emigration in gray-tailed voles, Microtus canicaudusNelson, Natasha 24 May 1996 (has links)
Graduation date: 1997
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Over-winter demography of the gray-tailed vole (Microtus canicaudus) in fragmented and continuous habitatsBrunkal, Heidi L. 25 November 1996 (has links)
Large scale disruption of natural habitats worldwide has led to concern over the
effects of habitat fragmentation on wildlife populations. Small scale experiments may be
a useful tool for discovering effects of fragmentation over larger landscape scales. I
sought to explore the potential for using voles as an experimental model system, at a
small scale, to discover mechanisms that may affect other species at different spatial
scales. I compared over-winter demography of gray-tailed voles, Microtus canicaudus, in
two experimental landscapes, consisting of fragmented and continuous habitat, to assess
the effects of habitat fragmentation. I chose winter as the time frame of the experiment
because it poses harsh conditions for voles and because seasonal bottlenecks may affect
population persistence. Population size, population growth rates, reproduction,
recruitment, survival and movements, were monitored using mark-recapture methods in
8, 0.2-ha enclosures planted with alfalfa. The habitat within the enclosures was
manipulated into 2 configurations of equal area, 1 large continuous patch (625 m��), and a
mosaic of 25 small patches (each 25 m��), prior to the introduction of 12 pairs of
animals/enclosure. I hypothesized that population size and growth rates, reproduction,
recruitment, and survival would be greater for vole populations in continuous habitats
than for populations in fragmented habitats. Additionally, I hypothesized that movements would be more restricted within fragmented habitat because the voles would perceive the
area between habitat patches as a barrier.
I did not detect significant differences between vole populations in continuous and
fragmented treatments. However, populations residing in fragmented habitat showed
higher variability over the study period. Populations in both treatments decreased
throughout the winter period and all became extinct by the end of the study.
Reproduction occurred only during the fall period, and there were no significant
differences between treatments. Movements were not different between treatments, or
between male and female voles, but movements did increase over time. Survival appeared
to be higher for male voles in continuous habitat than in fragmented habitat, but female
vole survival was similar between treatments. Survival was influenced by weather
conditions, and predation. These results contrast with a previous experiment during the
summer season, and indicate that seasonal bottlenecks may be important to consider
when studying habitat fragmentation. Extinction of populations in both treatments
demonstrates that small populations are extremely vulnerable to both environmental and
demographic stochastic events. / Graduation date: 1997
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Producing fiber flax using modern machinery and field rettingKennedy, Ralph C. 13 December 1996 (has links)
Fiber flax (Linum usitatissimum L.) production in the Willamette Valley ended in
Oregon around 1957 before newly developed technology and fiber cultivars were
available. The purpose of this research was to explore the use of modern methods and
new cultivars.
Field studies were conducted to evaluate cultivars and optimum cultural practices that
would produce the highest yield and best fiber quality in the Willamette Valley on
Woodburn silty clay loam. A study was conducted to assess the winter hardiness of fifty
flax cultivars.
The effect of four different pull dates on straw and fiber yield and fiber quality were
investigated at two sites in 1995 and 1996. Pulling in stage 2, 3, or 4 resulted in an
increase in straw yield over pulling in stage 1 in 1996. No differences were detected in
fiber yield or caustic weight loss in response to pull date in either year. An acceptable
pulling window is stages 1-3 (range of 900 to 1300 growing degree days). Retting took
13 weeks in both years. Rainfall during the retting period was 10.7 cm in 1995 and 6.9
cm in 1996.
A field study was conducted in 1995 and 1996 to test the effect of three nitrogen (N)
levels (50, 75, and 100 kg ha�����) and three fiber flax cultivars (Ariane, Cascade, and
Viking) on straw yield. There was a significant increase in yield with increased N levels
in 1996. Higher levels of N increased yield in all three cultivars in both years. Lodging
of 'Cascade' increased with increased N levels in 1995.
The effect of three planting dates on yield and stand density of Ariane fiber flax were
investigated in 1995. The 31 March planting date produced the most retted straw (9704
kg ha�����).
A fall-planted winter cultivar experiment was conducted during 1994-95 and 1995-96. In 1994-95, four varieties (Ariane, Texala, Viking, and Hyslop Cascade) had greater
winter survival than Linore, the check variety. Only Linore withstood the second winter. / Graduation date: 1997
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Developmental biology and phenology of the walnut husk fly, Rhagoletis completa Cresson (Diptera: Tephritidae) in the Willamette Valley of OregonKasana, Abdulmajid 26 July 1993 (has links)
Graduation date: 1994
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Investigating Groundwater Arsenic Contamination using Aquifer Push-Pull TestsDaigle, Ashley R., 1986- 06 1900 (has links)
xiii, 67 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / The bedrock aquifer of the Southern Willamerte Basin, Oregon, USA, is
contaminated with arsenic at concentrations as high as several ppm. Single-well
push-pull tests were conducted to investigate how microbial metabolisms control arsenic
occurrence and levels in the aquifer. Test solutions containing ethanol were injected into
the aquifer; dissolved gases, groundwater, and sediments were then sampled to monitor
the speciation of carbon, iron, sulfur, and arsenic. Ethanol amendment stimulated a series
of microbial metabolisms, including arsenate reduction, iron reduction, and sulfate
reduction. Arsenate reduction converts arsenate to arsenite; iron reduction produces
ferrous iron; sulfate reduction releases sulfide. Arsenite and ferrous iron then combine
with sulfide and form arsenic sulfide and iron sulfide minerals. Results of the
experiments demonstrate that the interactions among microbial metabolisms and mineral precipitation influenced arsenic contamination in the aquifer. These results shed new
light on potential bioremediation strategies in the area. / Committee in Charge:
Dr. Qusheng Jin, Chair;
Dr. Mark Reed;
Dr. Samantha Hopkins
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Influence of light on algal growth in the lower Willamette RiverWille, Stephen Arthur 01 January 1976 (has links)
During the summer of 1974 chemical conditions in the lower reaches of the Willamette River, Oregon were similar to those in other rivers currently experiencing nuisance algal growth problems. Temperature and chemical nutrients are not limiting. Relatively high populations of phytoplankton and productivity values for upstream periphyton beds and surface waters suggest moderately eutrophic conditions. However, with increased depth in the lower river, and a constant euphotic zone, the amount of photosynthetically available light is reduced. With sufficient depth and complete mixing the critical depth is exceeded. Primary productivity rates are subsequently limited by low light availability in the lower river.
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