B and C horizon samples from twenty four selected profiles along
a north-south transect in the Willamette Valley were examined for
possible correlation between shrinkage properties and kind of clay
minerals present.
Observations of linear shrinkage, weight loss from a condition
of maximum plasticity, and changing character of X-ray diffraction...
Water conservation and water quality are rapidly increasing in importance in all areas of the world. The ability to accurately measure soil water content and salinity, over a wide variety of conditions, is key to meeting this need. A set of forward prediction models and waveform interpretation algorithms to extract...
Sandy soils are among the least productive soils because of their inability to
store adequate water for plant growth. Their high percolation rate not only allows
water to move quickly beyond the root zone, but also washes nutrients below the reach
of plant roots. High evaporation occurs from the soil...
Experiments were carried out to study the movement of water and
halide anions in perched water tables or saturated zones in the soil
and upper rock mantle of eight different experimental sites located
on low hills near the western border of the Willamette Valley. At each
site the experimental procedure...
The objective of this study was to estimate the bulk densities and points on the moisture-tension curves and to determine their associated variances for some of the selected mapping units in Central Oregon. These variances will produce informations concerning the precision of the mean and the optimum sampling schemes, for...
Measurement of plant moisture stress of 1-2 m understory conifers
was made in "reference stands" on the H. J. Andrews Experimental
Forest in 1970-1972. Maximum stress each year (measured between midnight
and dawn) is closely correlated with the position of each community
along one axis of an ordination of the...
Soft white winter wheat is grown in western Oregon and requires a spring application of nitrogen (N) fertilizer for optimum production. Determining the amount of N to apply has been a challenge for growers. Wheat obtains N from two sources: soil and fertilizer. Both available and mineralizable N can be...
Soft white winter wheat grown in western Oregon requires a spring application of nitrogen (N) fertilizer for optimum production. Determining the amount of N to apply has been a challenge for growers because wheat is produced in numerous rotations that provide varying amounts of N to the wheat crop. Inadequate...
The over-arching theme of this work is that soil data affect the performance and realism of vegetation models with particular focus on their ability to predict or explain disturbances such as fire or disease. We tested the sensitivity of the Excel version of the 3-PG model to soil properties and...