Land managers, scientists, and the interested public are confronted with uncertainty about the impacts of salvage logging on soil productivity. In recent years, stand-replacing wildfires in the western United States have increased in frequency, prompting the need to evaluate the effect of post-fire treatments on forest ecosystem recovery. This study...
Fusarium spp. are among the most important pathogens of Douglas-fir
(Pseudotsuga menziesii) seedlings in bareroot nurseries. Currently the most effective
disease control method is soil fumigation with methyl bromide. As methyl bromide is
phased out, however, other disease management strategies may become more important.
We explored two alternative approaches to...
The Oregon Long-Term Soil Quality Project was initiated to identify soil
properties that respond rapidly to alternative management practices. Such practices
included winter cover cropping, which was implemented at two experimental research
stations and several grower fields throughout the Willamette Valley. The goal of this
thesis was to identify the...
There have been many studies that describe the protective degradation or metabolism of potentially harmful plant toxins, such as, mimosine from Leucaena leuconcephala, pyrrolizidine alkaloids from tansy ragwort (Senecio jacobaea), oxalate and some mycotoxins by rumen microbes. There are many cases of plant-related toxicoses suffered by ruminant animals where there...
Two native shrub species (Piliostigma reticulatum and Guiera senegalensis) are prominent vegetation components in farmers’ fields in Senegal. However, their role in nutrient cycling and ecosystem function has largely been overlooked. A study including both laboratory and field experiments was conducted to evaluate potential biophysical interactions of the two shrub...
A new high-throughput culturing (HTC) method using a low nutrient
heterotrophic medium (LNHM) has led to the isolation of many novel strains of
oligotrophic bacteria from marine ecosystems. Four strains belonging to a single
dade, HTCC2151, HTCC218OT, HTCC2178T and HTCC2188T, were isolated
from the coast of Oregon by the HTC...
Small pelagic fish represent a critical trophic link between plankton and large predators in marine upwelling ecosystems such as the California Current System. Populations of these fish are highly variable over time and are characterized by extreme fluctuations in abundance, which have significant ecosystem impacts. The causes driving
this instability...
Phytophthora vignae, causal agent of stem and root
rot of cowpea (Vigna unguiculata), was reported for the
first time in Sri Lanka. The pathogen was found in cowpea
field soils from 3 of 5 geographic regions sampled. Only
one site however, had plants exhibiting disease symptoms.
Of the eight cowpea...