Seasonal reducing conditions play an important role in the cycling of nutrients and soil pore water chemical constituents in the Willamette Valley. Long periods of soil saturation lead microorganisms utilizing organic matter as their carbon source to find alternative electron acceptors other than oxygen. Once oxygen has been depleted microorganisms...
Rapid and accurate analytical methods are needed to assess the impacts of agricultural chemicals on soil and water resources. Solid-phase extraction (SPE) was evaluated as an alternative method to conventional liquid-liquid extraction for the quantitative analysis of the herbicide DCPA and its metabolites in ground waters. Strong anion exchange (SAX)...
Much interest has recently been shown in using fecal samples to monitor
hormone concentrations in free-roaming animal populations. This process is noninvasive
and, therefore, provides easy sample collection and assures no stress-related,
physiological responses that might alter the hormonal data. Concerns have been
expressed, however, that the hormone concentrations detected...
Pole-sized, live western larch Larix occidentalis Nutt.) were inoculated with Ophiostoma pseudotsugae(Rumb.) von Arx or Leptographium abietinum (Peck) Wingf., two blue stain fungi associated with the Douglas-fir beetle (Dendroctonous pseudotsugae Hopkins), to assess their pathogenicity. Inoculation with O. pseudotsugae resulted in a significantly greater percentage of necrotic phloem compared to...
Surfactants, or surface active agents, are the active ingredients in detergents used for
domestic cleaning applications, such as dish washing and laundering. They are effective cleaning
agents by concentrating at interfacial regions, lowering the surface tension of water, and forming
micelles that solubilize oils (West, 1992). Surfactants are amphiphilic, because...
Leaves of healthy strawberry plants were inoculated with either vinclozolin-sensitive or vinclozolin-resistant isolates of Botrytis cinerea at one of three concentrations: 5x104, 1x105, and 5x105 conidia/ml. One week following inoculation, representative leaves were harvested and cut into 9mm2 leaf pieces. Some pieces were immediately plated onto selective Botrytis medium while...
Evaporative loss rates of pesticides, following application to turfgrass, were measured using the Backward-Time Lagrangian stochastic Dispersion model (Flesch, Wilson, Journal of Applied Meteorology, 34, pp. 1320-1332. All pesticides were applied to a 22.8 m x 22.8 m orchard ryegrass turf plot near Corvallis, Oregon. Solar radiation, ambient temperature, surface...
Polycyclic aromatic hydrocarbons (PAHs) are a class of usually planar
compounds consisting of fused aromatic rings that are formed by the incomplete
combustion of organic materials. PAHs are ubiquitous in the environment, coming from
a number of sources, such as cigarette smoke, the burning of wood for residential heating,
and...
Ontogenetic niche shifts are critical times in a fish's life that need to be passed for
survival, growth and recruitment (Gerking 1994, Osenberg et al. 1994). These niche
shifts are identified by a change in feeding from one prey type to another. These shifts in
feeding occur throughout growth and...