Vegetation as a soil-forming factor was studied under forest
transition and grass while attempting to keep other soil forming factors
constant in the western part of the Willamette Valley, Oregon. The
physiographic units consist chiefly of the interior foothills and slopes
formed from an old basaltic flow with some interspersed...
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)...
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...
Two small adjacent watersheds on the west-central edge of the
Willamette Valley of western Oregon were studied. Information was
gathered on existing conditions to determine the suitability of the two
watersheds for a paired-watershed study design.
A soil survey was conducted using slightly modified soil series
previously established for the...
The effluent from on-site sewage disposal systems has been
found to be a source of nitrates (NO
₃⁻
) in groundwater. Vegetation
has the ability to remove some of the nitrogen (N) from sewage
effluent as the solution moves through the soil around a disposal
trench, before it reaches groundwater....