Several investigators have recently called attention to the
fact that the flux equation for water movement in unsaturated soils
may not be an appropriate mathematical model for the development
of the theory of unsaturated flow phenomena.
An analytical theory is developed for the purpose of testing
the validity of the...
A sequence of soil profiles was sampled along a climate-vegetation transect on the dated Mazama pumice fall in central
Oregon. The <2 μ size fraction from each sample was characterized
with respect to the relative significance of amorphous and
crystalline components, and the individual minerals of the latter
group were...
Detoxification of atrazine in soils results from both chemical
hydrolysis and microbial degradation.
Infrared analysis was used
to study the hydrolysis of atrazine upon interaction with soil
colloids
and to ascertain the existence of enol, keto, and protonated-keto
forms of hydroxyatrazine.
Evolution of ¹⁴CO₂ from ¹⁴C-atrazine
and ¹⁴C-hydroxyatrazine was indicative...
The research presented in this thesis evaluated the effects of
uranyl (UO₂⁺⁺) upon the absorption of Li, Na, K, Rb, and Cl. Due
to the biological importance of Na and K, these two ions were
studied in the greatest detail.
The results of this research showed that, at UO₂⁺⁺ concentrations...
Incubation experiments with an acid poorly drained soil have
shown that the application of neutral soluble salts influenced the level
of extractable Mn. The application of a salt which lowered the soil
pH either increased the extractable Mn or retarded the oxidation
and/or fixation of extractable Mn. This effect was...
An investigation of Mn uptake by five-day-old excised barley
roots revealed that a metabolically-mediated process was involved.
In short-term experiments, the rate of Mn absorption was comparable
to that of the macronutrient cations. Like other metabolically
absorbed cations, the Mn absorption rate was a direct function of
the ambient concentration...
Wheat varieties of differential tolerance to Al were used in a
series of nutrient solution experiments to study the inhibitory effects
of Al on growth and nutrient uptake. The pH and the Al and P concentrations
were rigorously maintained to prevent the confounding
effects of Al and P precipitation and...
Mineralogical analysis of 3 upland soil profiles over Tyee parent
rock from the Alsea Basin Area, Oregon showed clear differences
among the 4 soil series represented. Soils from the area of higher
precipitation (over 80 inches, approximately) had no montmorillonite,
lower base saturation and cation exchange capacity, but no lower...