1,180 research outputs found
Diagnostic Testing for Nitrogen Soil Fertility
This publication defines the different types of diagnostic testing for nitrogen soil fertility
Managing Sodic Soils in Utah
This publication discusses how to manage soil with excess sodium while it\u27s becoming more prevalent in Utah
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Very low ozone episodes due to polar vortex displacement
The large-scale ozone distribution over the northern hemisphere undergoes strong fluctuationseach winter on timescales of up to a few weeks. This is closely linked to changes in the stratosphericpolar vortex, whose shape, intensity and location vary with time. Elliptical diagnosticparameters provide an empirical description of the daily character of the polar vortex. Theseparameters are used as an objective measure to define two characteristic wintertime vortexdisplacements, towards northern Europe and Canada, respectively. The large-scale structuresin both the stratosphere and troposphere and the 3D ozone structures are determined for bothvortex displacement scenarios. A linear ozone transport model shows that the contribution ofhorizontal ozone advection dominates locally in the middle stratosphere. Nevertheless, thelargest contribution is due to vertical advection around the ozone layer maximum. The findingsare in agreement with an EOF analysis which reveals significant general modes of ozone variabilitylinked to polar vortex displacement and to phase-shifted large-scale tropospheric waves.When baroclinic waves travel through the regions of vortex-related ozone reduction, the combinedeffect is to produce transient synoptic-scale areas of exceptionally low ozone; namelydynamically induced strong ozone mini-holes
Value of beef performance records
"Individual performance records are useful for selecting superior performing cows and bulls and for culling undesirable animals from the herd. The Missouri Beef Cattle Improvement Programs are available to beef cattle breeders through local University of Missouri extension centers. · Flexibility of the programs helps both purebred and commercial breeders in their selection and breeding programs. The cow-calf man can use these programs as tools to check the performance of each animal from birth until it is added to the herd or slaughtered. By using these programs, you can evaluate an individual animal's genetic merit within a herd. This is important since new genes are not created and herd superiority comes from measuring economic traits and selecting genetically superior individuals."--First page.John W. Massey, James E. Ross, and D. W. Vogt (Department of Animal Science, College of Agriculture)Revised 2/85/8
Comparative value of dry-rolled corn, distiller’s dried grains, and wheat middlings for receiving diets
Two 28-day receiving experiments were
conducted using 620 exotic × British cross
steers to evaluate differences in growth performance,
morbidity, and mortality when fed diets
containing dry-rolled corn, distiller’s dried grains
with solubles, or wheat middlings. All diets
contained approximately 60% concentrate and
40% roughage (alfalfa hay). Gain and efficiency
tended to be poorer for cattle fed the wheat
middling-based diet than for those fed corn. No
notable differences were evident in terms of the
percentage of cattle treated for respiratory
disease. Feed intake and daily gain were improved
slightly when corn was replaced by
distiller’s dried grains, but efficiency was not
changed. However, the incidence of respiratory
disease also was higher for cattle fed the distiller’s
grains diet in comparison to corn
Theoretical Analysis of STM Experiments at Rutile TiO_2 Surfaces
A first-principles atomic orbital-based electronic structure method is used
to investigate the low index surfaces of rutile Titanium Dioxide. The method is
relatively cheap in computational terms, making it attractive for the study of
oxide surfaces, many of which undergo large reconstructions, and may be
governed by the presence of Oxygen vacancy defects. Calculated surface charge
densities are presented for low-index surfaces of TiO, and the relation of
these results to experimental STM images is discussed. Atomic resolution images
at these surfaces tend to be produced at positive bias, probing states which
largely consist of unoccupied Ti 3 bands, with a small contribution from O
2. These experiments are particularly interesting since the O atoms tend to
sit up to 1 angstrom above the Ti atoms, so providing a play-off between
electronic and geometric structure in image formation.Comment: 9 pages, Revtex, 3 postscript figures, accepted by Surf. Scienc
Infection dynamics: from organ to host population
A symposium discussing collaborative research work on infectious diseases dynamics was held at Queens' College, University of Cambridge on 25 October 2006
Factors affecting zinc uptake in cropping systems
Zinc availabilities can change with different cropping management
practices. The objective of this study was to identify some of the causative
factors associated with previous crops contributing to Zn uptake
differences in a subsequent crop. Field studies over 3 yr evaluated the
Zn availability after four precropping treatments: bean (Phaseolus
vulgaris L.), corn (Zea mays L.), wheat (Triticum aestivum L.), and
fallow, across two Zn fertilization rates (with and without 11 kg Zn
ha-1 as ZnSO4), using the 'Viva' bean as a test crop. Soil samples
taken before and after the test crop were analyzed for extractable P,
Zn, Cu, Mn, and Fe, and organic matter. Soil respiration during the
test crop was periodically estimated the last cropping year. Whole
plant samples estimated nutrient concentration and uptake. Soil Zn
extracted by diethylenetriaminepentaacetic acid (DTPA) was increased
by Zn fertilization but not affected by precropping treatments.
Zinc uptake by bean was significantly higher after precropping with
corn and lower after fallow regardless of Zn fertilization. Uptake
differences were most pronounced during early plant growth. Phosphorus
and Cu uptake varied with treatment in a similar pattern as
Zn uptake, and were positively correlated with each other. Zinc uptake
was also positively correlated with soil organic matter and negatively
correlated with soil P. Soil respiration rate was significantly
lower after the fallow treatment compared with other precropping
treatments. Vesicular-arbuscular mycorrhiza (VAM) colonization in
the test crop roots was higher after corn and lower after fallow regardless
of soil Zn concentrations. Colonization was positively correlated
with Zn, P, and Cu uptake during early plant growth. The
VAM colonization, soil respiration, and DTPA-extractable Zn were
selected by a stepwise regression procedure as the important variables
affecting Zn uptake during early plant growth. These results emphasize
the importance of the soil's biological activities on Zn availability
and may help explain some field observations where chemical soil tests
appear to fail
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