The effects of broadcast gypsum on infiltration rates, crusting,
aggregate stability, and runoff and sediment yields were analyzed
during the winter months on three West Oregon soils. The results were
used to evaluate its utility as a management tool to help control
erosion.
An application rate of two metric tons...
Surface and subsurface hydrological parameters affecting overland flow from cultivated land were studied in three small sub-watersheds located in the western foothills of the Willamette Valley. The sub-watersheds, which ranged in size from 0.46 to 6.0-ha, were fall-planted to grass or small grain. The parameters studied were infiltration, rainfall, runoff...
Modern agricultural erosion was studied using ¹³⁷Cs from
fallout as an indicator of erosion/deposition. The study area was a
285 ha agricultural watershed in the hilly western margin of the
Willamette Valley, a high winter rainfall zone in which fall-planted
crops are commonly grown.
Objectives of the study were (i)...
Diclofop-methyl [me yl 2-(4-(2,4-dichlorophenoxy) phenoxy) propanoate] hydrolysis, degradation, and leaching were studied in field and laboratory experiments. Greater than 75% of the applied diclofop-methyl hydrolyzed to diclofop in 2 days at 4°C, the prevailing soil temperature during western Oregon winters. Degradation beyond the diclofop molecule, also an active herbicide, was...
The emission of sulfur oxides from anthropogenic sources represents a potential threat to terrestrial ecosystems. Sulfate, the most highly oxidized form of sulfur, is the most common form of inorganic sulfur in most soil environments. The sorption of sulfate may influence the alkalinity of the soil solution and as a...
The variability in morphologic, chemical, and physical soil
properties within the Willakenzie silty clay loam, 2 to 12 percent
slopes, map unit in Yamhill County, Oregon was measured.
The objectives of the study included (1) describing the frequency
distributions of individual soil properties, (2) measuring the
taxonomic composition of the...
Efficiency of nitrogen fertilizer uptake by soft white winter
wheat (Triticum aestivum L.) was measured over two cropping seasons
across a range of soils and cropping histories in the Willamette
Valley. Fate and potential losses of applied nitrogen were also
assessed over a seventeen month period.
In both cropping seasons,...
Clay mineral genesis was studied in soils representative of several
different geomorphic surfaces in western Oregon, ranging in age from
Pliocene-early Pleistocene to late Pleistocene. Soil solution studies,
clay mineralogy, and soil raicromorphology were employed to provide
evidence of clay mineral synthesis and interpret soil genesis.
Soils at each study...