Cheatgrass (Bromus tectorum L.) and yellow starthistle (Centaurea
soistitialis L.) have invaded over 3 million ha of grasslands in the western U.S.
Future management will require an understanding of the conditions,
mechanisms, and processes which control species dominance, community
dynamics, and desirable plant establishment in these alien dominated annual
rangelands....
The purpose of this study, to examine the relevance of U.S.
graduate education in agriculture to careers in agricultural
development of East African agriculturalists, was examined in
terms of three problems:
Problem 1: Was U.S. graduate education in agriculture
relevant to careers in agricultural development of East
African agriculturalists?
Problem...
The purpose of this study was to determine the concerns of past participants of the Summer Agriculture Institute regarding the use of agriculture as a context for teaching and to determine how they implement curriculum integration. The study used the Concerns-Based Adoption Model as a theoretical framework, which resulted in...
Freeze/thaw cycles are numerous in agricultural soils of the Pacific Northwest. Potential loss of soil by erosion is high whenever a soil thaws from the surface creating a saturated soil overlying an impermeable frozen layer. Field studies were conducted to investigate the effect of surface residue on soil freezing. Residue...
The effect of a static quadrupole interaction on the 133-482 Kev
gamma-gamma angular correlation in Ta-181 has been studied by the
delayed coincidence method. Using a source of Hf-181 in polycrystalline
hafnium metal, the anisotropy was measured as a function of
time between the formation and decay of the 482...
A number of investigators have proposed equations to predict
the permeability of porous media. Most of their equations are based
on the distributions of the sizes of the various contributing pores in
the medium. Presently the pore size distributions of agricultural
soils are most commonly obtained from soil water release...
Atmospheric boundary layers become stably stratified at night over land when the surface becomes colder than the air layer above. In stable nocturnal boundary layers (SNBL), turbulence becomes weak and intermittent, terrain-induced phenomena such as drainage currents or gravity-waves emerge and the surface heterogeneity is enhanced. Because of their complexity...
Laboratory experiments were used to investigate the mechanism
of plant response to water stress by determining the sensitivity of leaf
elongation, photosynthesis and transpiration in young corn plants to a
decrease in leaf water potential.
In initial experiments, 9 day old corn plants were grown at soil
water potentials of...
At present the adsorption kinetic of ions by soil particles is considered to be a surface reaction. When the transport of solutes in soils is described using the one-dimensional flow equation, it becomes a serious problem that lateral diffusion of ions from the bulk solution towards the soil surfaces is...
