In horticultural nurseries for container-grown plants, production and sales have been threatened by the presence of a quarantined plant pathogen, Phytophthora ramorum (causal agent of sudden oak death). Infested nursery beds are an important source of P. ramorum, which can initiate disease through movement with surface water to infect roots...
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...
The objectives of this thesis were to evaluate the responses of soil microbial communities to physical and chemical disturbances, and associate these responses with soil functional stability and changes in soil quality. The first study consisted of application of heat shocks (HS) to soils with contrasting land use history to...
This dissertation reports on four related, though separate projects. The first project details the process of carrying out a digitally augmented soil mapping (DSM) effort alongside an ongoing survey in Oregon's Ochoco National Forest (ONF) using a Random Forest algorithm. The second chapter describes a initial soil survey in Oregon's...
There are a number of problems associated with urban expansion and as cities continue
to grow the integration of green roofs can help to ease and offset many of them. This study
uses a combination of moss and Sedum as vegetation for experimental green roof sections in
order to test...
Full Text:
Ed Peachy & Aaron Heinrich
MariaDragila & Gloria Ambrowaik
Andy Phillips & Hannah VanHoosen
Soil water repellency may be influenced by microbes whereby they produce aliphatic constituents (non-wetting materials) that coat the soil particles when they are subjected to desiccation stress.
Shrinkage cracks in soil function as a dominant control on the partitioning and distribution of moisture fluxes in the vadose zone. Their dynamics influence moisture balance and control water availability for runoff, deep infiltration, and near-surface storage. We present a new low-cost field instrument to monitor the temporal change in...
Contamination events at Oak Creek, which runs through Oregon State University Research lands, prompted investigations into alternate transport mechanisms for moving liquid effluent from OSU Diary lands to Oak Creek. Magnetometer surveys conducted at the Diary identified magnetic signatures spatially associated with sub-surface locations of drain tiles, a 12-inch pipe,...
Surface tensions of high-salinity solutions are significantly different from those of pure water. Our objective was to develop and test a methodology to determine whether these surface tension effects predictably alter imbibition into dry and moist porous media. Static and dynamic experiments were performed using four grades of quartz sand...