1. Al-Mashhdany, Showket Abdalah. 1978. Chemical control of the annual weeds of southern Arizona rangeland. Tucson, AZ: University of Arizona. 55 p. M.S. thesis.
Pre-emergence winter applications of herbicides were
unsatisfactory. Dicamba (2 kg/ha) was most effective and removed
88% of dormant winter weeds. Post-emergence application of
glyphosate and picloram were most effective. Most summer
treatments allowed good to excellent control of both broadleaf
and grassy weeds. Atrazine and dicamba (2 kg/ha) gave 97-100%
control. Tebuthiuron (1 kg/ha) removed all of the annual summer
weeds. Post-emergence summer treatments showed that dicamba,
MSMA, and picloram removed all weeds.
Blue grama plants burned in the field using four fuel levels
decreased in dry weight production by about one-half, regardless
of the amount of fuel. Crude protein content was higher on the
burned plants. No plants were killed by the fire. The dry
weight produced by blue grama and sideoats grama two months after
laboratory-burn treatments was inversely related to the
temperature and length of time. Mesquite damage by fire was
variable with respect to fuel loads. Oak bark was a better
insulator than that of mesquite. Heat resistance in young
mesquites appeared to be a function of age.
The cactus wren's territory is used for mating, nesting, and
as a feeding ground for the young. It is also retained as a
roosting area for the remainder of the year. Autumn roosting
nests seldom remained intact until the next year's breeding nest
was begun. Average time from beginning of construction to the
laying of the first egg was about 14 days. Variation in time of
the laying of the first egg was great.
Revised 1957, refer to Anderson et al. 1957.
Several factors, (site quality, rainfall, etc.) considered
in reseeding, including methodology, are discussed in detail with
species recommendations for various desert grassland sites.
Serology tests for 6 diseases were run on blood samples from
a total of 183 mule deer and white-tailed deer from several
areas. Of these, 10% had a significant test for BTV, 17% were
positive for PI-3, 30% were positive for IBR, and 16% were
positive for BVD. Only a single whitetail sample was positive
for Leptospirosis and none for Brucellosis. Values for 18 blood
chemistry components are listed for 35 mule deer samples from
three areas. White-tailed deer values are pooled for all areas
from which they came.
Plant samples from fertilized plots had higher cell-sap
concentrations than check plots. Fertilizer increased the number
of individual plants, except where more luxuriant growth resulted
in competition. Fertilized plants showed increases in the number
and length of leaves. An increase in density of plant cover,
palatability, harvested dry weights, and seed production was
noted on all fertilized plots.
The average daily forage consumption (absolute values) of
Arizona jackrabbits ranged from 5.6% to 6.7% of body weight and
5.8% to 6.5% of body weight for antelope jackrabbits.
Palatability tests were made on 32 grass species, 47 weed
species, and 21 species of browse. Jackrabbits appeared to
prefer plants in order of weeds, grasses and browse with the
first two making up the major and about equal parts of the diet.
It is suggested that once range deterioration is well under way,
jackrabbits may be a partial cause of overgrazing, and in the
final stages of deterioration may be the primary cause of
depletion. When competition is considered to be direct, 62 _ 7
Arizona jackrabbits and 48 _ 2 antelope jackrabbits consume the
equivalent of one 1,000-pound range cow.
Arizona and antelope jackrabbits fed in captivity on
different types of food show certain characteristic depositions
of fecal material. The age and weight of mature animals do not
affect the number or weight of pellets voided by either species
of jackrabbit. Pellet count remains constant, on the average,
regardless of age, sex, size or species of rabbit. A jackrabbit
of either species voids an average of 531 _ 27 pellets per day
when eating green, native forage material. Pellet weight and
weight of food consumed show a direct linear relationship. When
eating green native forage the animals of either species void
about 55% of the weight of ration ingested. Character of forage
consumed has a greater effect upon pellet weights than upon
pellet counts. Some uses of pellet weights and counts are
outlined. The use of pellet weights to determine forage removal
is suggested.
This study assessed the relative survivability of 12 native
grasses transplanted between 1935 and 1937. Results indicated
that under total protection (from cattle and rodents), Bouteloua
eriopoda, Trichachne californica, Boutelouz curtipendula,
Boutelouz chrondrosioides, Aristida divaricata, Heteropogon
contortus, and Muhlenbergia porteri exhibited greater survival
rates in decreasing order. Under cattle protection only,
Boutelouz curtipendula appeared most successful. Four other
species failed to appear in their subplots.
Over 77% of ecosystem nitrogen was contained in the soil,
20% in shrub phytomass, and 3% in understory phytomass and
litter. Carbon was almost equally distributed between soil and
phytomass. Total ecosystem phytomass for mesquite and palo verde
were similar and averaged 5.8 kg/m2. Soil nitrogen and carbon
decreased with distance from shrub centers. Seasonal and annual
changes in nitrogen and carbon were found for many components of
two ecosystems.
A scale platform was suspended from a supporting structure
by four strain gage load rings. Weight supported by the load
rings triggers an electrical signal that is recorded by an
oscillograph. Signal magnitude is correlated with animal weight
through calibration of the system. Field tests proved the method
adequate and reliable.
Chlorinated hydrocarbon insecticide emulsions penetrated
least in arid soils from Arizona and Oregon and most in soils
from Missouri in a test of seven soils from various parts of the
United States. Soil moisture at application time appeared to
enhance penetration. After 24 hours in most tests, more than
half of the insecticide applied was found in the upper 3/4 inch
of soil. The parts per million of insecticide measured in 6
layers of soils did not differ appreciably in samples taken 1, 4,
and 24 hours after application. Chlordane, dieldrin, and
heptachlor were the insecticides tested.
Results showed that on fertilized soil, significant
increases in herbage production, number of stems per plant, and
crude protein content were obtained for all levels of water.
Soils not fertilized showed no gain above normal levels. Soil
nitrate was decreased at the normal and above normal water levels
on fertilized soils.
A short report on research being conducted on absorption,
movement, and toxicity of organic and inorganic herbicides
applied to mesquite.
16. Blair, Byron O. 1951. Mesquite seed and seedlings
response to 2,4-D and 2,4,5-T. Botanical Gazette.
112(4): 518-521.
This paper reports on studies of germinating seeds and young
seedlings of mesquite. Seeds and seedlings were found to be
responsive to 2,4-D and 2,4,5-T but not as sensitive as other
desert woody plants. Concentrations above 1 ppm of 2,4,5-T were
more toxic than 2,4-D. Applications of higher concentrations (>1
ppm) to mature plants as foliar sprays have not resulted in
kills, indicating either lack of absorption and translocation or
greater resistance of mature plants.
This paper reports on techniques used and quantitative data
obtained on translocation of 2,4-DI, with and without added
adjuvants, applied as herbicidal concentrations in spray form to
foliage of velvet mesquite seedlings. A simple technique by which
seedlings tops were isolated for spraying is described. Results
showed that 96 hours after spraying, less than 3% of the
deposited radioactive material had moved from the tops to tissue
located more basally.
Several herbicidal solutions injected into mesquite stems in
the absence of air show that time of year was the most important
factor affecting the amount of solution intake. Lateral movement
of herbicides was negligible and downward movement was limited.
The sensitivity of the model to the method used for the
calculation of potential evapotranspiration (PET), actual
evapotranspiration (AET), and soil moisture movement was
evaluated using actual data. The PET method has a negligible
effect, but the AET method selected was important to soil
moisture estimation, with the more complex methods giving the
most accurate results. The model explained 85% (R=0.92) of the
variation in observed values over the period of calibration and
64% (r=0.80) over the period of validation.
Root systems of species of Aristida, Bouteloua and
Trichachne were restricted to the upper 7 inches of soil, with
depth penetration of roots influenced by characteristics of the
soil. Grazing affected root development by reducing the amount
of branching of first-order roots and, in two species of
Bouteloua, by decreasing total root density. Root diameter was
not affected.
Burning before summer rains will kill most of the burroweed
and make deep inroads into cholla, prickly pear, and barrel
cactus. Burning temporarily increased soil fertility by
releasing small amounts of nitrogen and soluble minerals.
Overall grass density was reduced one-third, but the loss was
regained by the end of three growing seasons.
Contrary to popular opinion, cattle do not go directly from
salt to water but may graze several hours between salting and
watering if salt and water are some distance apart. Salt, or
meal-salt mixture, placed on lightly grazed areas, aids in
obtaining more uniform utilization. Best results in the
Southwest can be obtained during the cool months of the year when
cattle water less frequently.
The benefits derived from hauling water to livestock on the
range include (1) reduced feed bills, (2) reduced grazing
pressure around permanent watering places, (3) better utilization
of remote parts of the range, and (4) better control and care of
the livestock.
A description of range management practices on a well-
managed range livestock operation in southern Arizona. Good
range management and good animal husbandry practices are the
essentials of this rancher's successful operation.
Changes in numbers of burroweed and mesquite were directly
correlated with grazing pressure. Total protection was
insufficient to decrease the numbers of burroweed materially and
failed to retard the increase of mesquite sufficiently to appear
as a usable control method. Increases of other shrubs showed
little relationship to protection.
Burning produced its greatest effect in the growing season
immediately following burning. Burroweed was effectively killed
by burning in June and responded to climactic changes by
increasing in numbers during periods of above-average winter
precipitation. Fire and drought had inconsistent effects on
mesquite and cactus. Most perennial grasses lost basal area
during the growing season immediately following the first burn.
Drought appeared to exert a greater negative influence on
perennial grasses.
One-third of velvet mesquite seedlings burned when 8 and 12
months old were top-killed only and sprouted later from the base;
the other two-thirds were completely killed. Age of seedlings
had no effect on the results.
Twenty-five percent of mesquite trees were killed on an area
with lehmann lovegrass ground cover compared to 8% on an area
with black grama. Ninety percent of black grama plants and more
than 98% of lovegrass plants were killed. Many new lovegrass
seedlings became established on both areas.
Because burroweed has a taproot and is primarily a spring
grower, summer yields of annual and perennial grasses were only
moderately affected by burroweed. Perennial grasses competed
strongly with annual grasses and burroweed during the summer
growing season.
Immediate effects of fire on perennial grasses lasted only 1
or 2 years. Burroweed was easily killed but came back quickly
with adequate cool-season moisture. Fire was relatively
ineffective against mesquite and fairly effective against cactus.
Measurements of phenological development, herbage
production, basal area, and density of annual and perennial
grasses and of burroweed over a 4-year period show that
production of each class of plant was affected to some extent by
each of the others, except that annual grasses had no effect on
burroweed crown area. Production of Arizona cottontop, the
dominant perennial grass, was restricted about 25% on plots with
annual grass or burroweed competition and 46% by both together.
Annual grass production averaged 18% lower with burroweed
competition and 44-54% lower with perennial grass competition.
Burroweed crown area increased 220% on plots with no perennial
grass but only 111% on plots with perennial grass competition.
Presence of burroweed reduced perennial grass yield only
moderately because the root systems of burroweed and grass do not
overlap greatly, and their main growth periods are at different
seasons. High evaporation rates during the summer growing season
masked most differences in moisture extraction between species.
During the winter-spring growing period, on the other hand,
burroweed depleted the available soil water rapidly, while water
loss on perennial grass plots was little more than from bare
soil.
Daily minimum soil temperatures were lowest at the surface
and increased with depth; daily maximum soil temperatures were
highest at the surface and decreased with depth. Diurnal
variation was greatest (as much as 75 F) at the surface and
lowest (1 or 2 F) at the 24-inch depth. Soil temperatures at
the 3-, 12-, and 24-inch depths ranged mostly between 40 and 60
F during the winter months and between 70 and 90 F during the
summer months. Absolute maximum and minimum temperatures
recorded were 141 and 29 F.
This comprehensive study discusses in great detail the
phenological development of Arizona cottontop. Special attention
is given to time-growth and moisture-growth related functions.
In a 10-year study, perennial grasses increased in response
to favorable rainfall and mesquite control and did better on fine
than on coarse textured soils. Because of heavy spring use,
grazing November to April was less favorable for perennial
grasses than May to October or yearlong grazing.
Shrubs are most susceptible to burning in June.
Opportunities for planned burning are limited in areas of
insufficient herbaceous ground fuels. Some perennial grasses
(lehmann lovegrass, Santa Rita threeawn) survive burning very
well, others survive intermediately well (Arizona cottontop,
Rothrock grama, tanglehead), and others are easily damaged (black
grama, tall threeawns).
Fourwing saltbush was seeded and transplanted into native
stands of (a) almost pure creosotebush and (b) velvet mesquite
with burroweed understory, in southern Arizona. Burroweed and
creosotebush were controlled by picloram spray and by grubbing.
The mesquite was killed on half of the burroweed plots.
Establishment and survival of saltbush was much higher on the
creosotebush site than on the mesquite site, presumably because
calcareous (pH 8.0+) soil at the creosotebush site was more
suitable than the noncalcareous neutral soil at the mesquite
site. Transplants survived better on grubbed plots than on
sprayed or check plots. Seedlings survived betteron sprayed or
grubbed plots than on check plots. However, after 3 years stands
were reduced to 650 and 46 plants per acre on the creosotebush
and mesquite-burroweed area respectively.
Precipitation during the study period was somewhat
deficient, and infiltrated soil moisture barely reached the 3 m
depth. Results were limited to moisture changes within this 3-m
soil depth. The pattern of soil moisture use by velvet mesquite
was high during spring (April to June) and summer (July to
September), and low during fall (October to December) and winter
(January to March). Roots withdrew soil water first from areas
close to the tap root and at shallower depths. As the growing
season advanced and available moisture decreased, roots withdrew
increasing proportions of water from areas increasingly farther
away from the trunk (to at least 19.3 m) and from increasingly
deeper soil layers. During the growing season (April to
September), rates of soil water extraction differed strongly with
horizontal distance from the trunk of the tree. Rates of
extraction within the layer of active moisture withdrawal
differed little at different depths, although the active water-
withdrawal layer became increasingly thicker as the season
advanced.
Perennial grass production in the semidesert grass-shrub
type (with and without a velvet mesquite [Prosopis juliflora var.
velutina (Woot.1 Sarg.] overstory) was dependent primarily on
current summer rainfall and previous summer rainfall. The
influence of previous summer rainfall was an interaction effect--
not a direct effect. The best overall relationship involved
current August rainfall, previous June through September
rainfall, and the interaction product of these two. However, the
interaction product alone yielded estimates essentially as good
as the multiple regression, and explained 64-91% of the year-to-
year variability in grass production. Winter precipitation had
no consistent effect on perennial grass production the following
summer. The depressing effect of mesquite on perennial grass
production was most noticeable at low rainfall levels and became
minor at high rainfall levels.
Production of native perennial grasses and seeded lehmann
lovegrass was measured periodically for 21 years on a semidesert
area where velvet mesquite was controlled by 2,4,5-T aerial spray
and on an adjacent unsprayed area to determine how mesquite
control would affect grass production and how long the effect
would last. Grass production on the sprayed area increased
dramatically during the first 5 years in a time-dependent
relationship in response to the higher levels of available soil
moisture. During the last 12 years, changes in lovegrass
production were associated with changes in rainfall of the
current and previous summers and of the intervening winter (two
separate variables). Because of the strong competition from
lovegrass, native grass production during the last 12 years did
not show its usual relationship with summer rainfall, but
decreased gradually and consistently on both the sprayed and
unsprayed areas. At the end of the study period, native grasses
provided only 10% of the total perennial grass production on the
sprayed area and 20% on the unsprayed. Increased grass
production, resulting from the mesquite control treatment and
seeding, paid for the treatment within 4 years, and the sprayed
area was still producing more grass than the unsprayed area 20
years later.
Mesquites used water consistently to a depth of 3 m and
outward to 10 m beyond the crowns, but use at 15 m was limited
mainly to drier periods when water supplies closer to the trees
were depleted. With the start of spring growth, water was
extracted most rapidly from the surface layers. As the season
advanced, the water supply zone became increasingly thicker.
Rates of extraction were highest immediately after recharge in
early spring and early summer, and lowest in late fall.
Differences in available water in the soil accounted for 72-88%
of the variation in rates of extraction. The competitive effect
of velvet mesquite on perennial grasses is most severe in the
upper 37.5 cm of soil under and near the mesquite crowns, and it
gradually decreases with distance into adjacent openings. The
competitive effect in the openings is much more severe in dry
years than in wet years.
Soil water is recharged in the semidesert Southwest during
the usual winter precipitation season and again during the usual
summer rainy season. The amount and depth of recharge varies
widely, depending primarily on the amount of precipitation and
secondarily on storm character, soil texture, vegetation cover,
and evapotranspiration. Soil water depletion patterns and
amounts differed among species, between plants and bare soil, and
between seasons. Compared to evaporation from bare soil, water
extraction by plants was much faster but at more variable rates.
Essentially all available soil water was used by plants or
evaporated during most depletion periods.
Cattle preferred Arizona cottontop earlier in the season,
September through June, than any of the lovegrasses. Utilization
of lehmann lovegrass lagged behind all other species until late
in the spring. Otherwise the general patterns of use of the
native and introduced grasses were similar. The results suggest
that management of a semidesert, grass-shrub range with a mixture
of native grasses and lovegrasses should be no more difficult
than managing for native perennials alone.
Changes in vegetation were caused by three main factors:
year-to-year variation in precipitation, management practices,
and mesquite control.
Changes in herbage production, basal intercept, and grazing
use of perennial grasses, herbage production of annual grasses,
and crown intercept of shrubs and trees were related to changes
in rainfall, presence or absence of velvet mesquite, and to
differences in soil, topography, and salting. Over a 10-year
period, mesquite control increased perennial grass production
52%. Perennial grass production was highly dependent on both
last and current summer rainfall, indicating that 2 years are
required for recovery from a 1-year drought. Too heavy use
greatly restricted production in wet years that followed dry
years. Because of the strong relationship between rainfall and
grass production, stocking rates could be estimated as accurately
from rainfall as from grass production.
Rumen-fistulated steers consistently selected a diet higher
in crude protein than hand-clipped samples of the major available
perennial grasses. The excess of rumen protein over grass
protein depended on the availability of higher-protein shrubs and
annual forbs that supplemented the perennial grasses, and on
selection of high-protein parts of the grasses. Since the
abundance of these high-protein forages varied greatly with time,
the protein content of grass clippings did not reliably indicate
the protein level in the steers' diet.
Aerial spraying of velvet mesquite in two successive years
with 2,4,5-T killed 36-58% of the trees and reduced mesquite
foliage 86-95%. Increased herbage production of perennial
grasses more than paid the treatment cost within 3 years.
This study presents information on physiology, metabolism,
and life history of Geococcyx californianus.
A description of a study of two scarps of 2-3 inches in
height involving seismic work, stratigraphic mapping, and
topographic surveys of scarp morphology is presented.
There is a clearly defined normal tendency of cattle to
graze some plants at a height of 2 inches or less. A 15-25%
balance of ungrazed forage at the close of the grazing season is
recommended. Any attempts to fully utilize 75-85% of low
preference grasses would result in overuse of preferred grasses.
Tanglehead and bush muhly supply valuable forage during drought
periods.
A complete description of the method is provided, with
additional emphasis on sampling units and data analysis.
The method utilizes the relationship existing between the
amount of a grass stand grazed to a stubble height of 2 inches or
less, the amount grazed above a 2-inch stubble height, and the
ungrazed complement. Advantages and disadvantages are discussed.
Under conservative grazing, 50-75% of palatable species in a
normal year would remain unused at the close of the grazing
period.
The method is based on the relationship of the percentage of
close grazing to the percentage of total use. The method can be
learned in short time and yields results within 10% accuracy.
Composition of the perennial grass population of mesa and
foothill types of semidesert grassland range varied significantly
with the general intensity of grazing to which they are commonly
subjected. Relative amounts of common perennial grasses showed
the early changes toward range recovery or toward range
deterioration better than any other indicator.
When the productivity of the range has not been greatly
impaired by prolonged overuse and erosion, the rate of range
recovery under conservative grazing was approximately equal to
the recovery rate obtained under total protection from grazing by
domestic livestock.
Tall, coarse-stemmed grasses such as Arizona cottongrass,
sideoats grama, and black grama attained a high percentage of the
total perennial grass cover under long periods of protection.
Populations of relatively unpalatable deep rooted shrubs and
trees were comparatively slow to change in response to
conservative grazing or to total protection from grazing by
cattle.
Primary forage grasses were more abundant on areas that
received light or no grazing. Both secondary and primary grasses
produced new plants each year, but secondary species usually
produced greater numbers. Some black grama plants survived as
long as 14 years, but Rothrock grama lived only 3 years.
Plant cover did not vary significantly among grazing
treatments. Cover of mesquite reflected distribution before
treatments. Total grass cover appeared to vary inversely with
mesquite cover. Cover of lehmann lovegrass was more dependent on
the distribution of native plants than grazing treatments.
Courtship behavior was related to the presence of tergal
glands in the alates. In Paraneotermes it was found that the
presence of tergal glands in both sexes, and probable production
of a sex pheromone by these glands, could be related to the
different activities in their courtship repertoires. This was
not the case with Pterotermes and Marginitermes.
The persistence and degradation of heptachlor varied
considerably by location in tests in five areas of the United
States. Relatively high values for 1-hydroxy-chlordene,
representing approximately 60% of the insecticide in the soil,
were obtained for extracts of a Quincy loamy fine sand from
Oregon. Significant amounts of 1-hydroxy-chlordene were found in
the extracts of Lakeland sand from Florida. Generally,
heptachlor epoxide represented only a small fraction of the
insecticide present in the soil.
Because present recommendations for termite control by soil
application of chlorinated hydrocarbons were developed on soils
and for termites in southern Mississippi, field tests were
established at seven locations to compare control of the various
species of termites in different soils and climates. In the upper
4 inches of soil, the amount and distribution of insecticide
residues and degradation products varied considerably for the
different locations 3 years after application. Differences in
initial penetration may have been a major cause for this
variation. In 24 hours the insecticide emulsions penetrated
least in arid soils in Arizona and Oregon and most in wet soil
from Missouri. This paper reports the results of laboratory
studies into the factors influencing soil penetration by
insecticides. A mixture of aldrin, dieldrin, and heptachlor was
applied as a water emulsion to columns of soil obtained from the
field test locations.
Differences in persistence and degradation of chlorinated
hydrocarbons attributable to differences in soil properties were
observed after 1 year of weathering. More insecticide was lost
from surface layers than from lower soil layers. Heptachlor was
affected most by weathering.
Variations in penetration and persistence of aldrin,
chlordane, dieldrin and heptachlor in different soils and
climates were found to be affected by soil types, soil moisture
content, and climate and may subsequently influence the
effectiveness of treatment.
The information, procedure, and methods outlined are based
on the results of systematic studies in New Mexico and Arizona
(SRER). Various methods of plant establishment are discussed.
Ecotypic differentiation as a response to climatic
conditions was studied in an adaptable grass species, Sitanion
hystrix (Nutt.) J. G. Smith. Twelve collections were obtained
from seven states: Arizona, Colorado, Nebraska, Nevada, New
Mexico, South Dakota, and Utah. The collection sites varied in
elevation from 1,380 to 2,980 m and in annual precipitation from
310 to 739 mm. Plant materials were grown under uniform
conditions in a transplant garden and a growth chamber.
The effective growing seasons at the original collection
sites were apparently as limited by moisture stress as by cold
temperatures. Relative phenological development could be
predicted by a climatic scale representing temperature and
moisture conditions at the original collection sites. Plant size
and dry matter production could not be predicted as reliably,
suggesting that the primary factors that influence morphological
and production characteristics may be more numerous or complex
than those that influence phenology.
The populations represented in this study have adapted to
different climatic conditions primarily through variations in
timing of phenological development and in rate of growth. No
differences in water use efficiency were found. Under uniform
conditions: (1) plants from warm, dry habitats flowered early and
had low dry matter production; (2) plants from habitats with
moderate temperature and moisture conditions flowered latest and
had relatively high dry matter production; and (3) plants from
cool, wet habitats flowered early and had relatively high dry
matter production. Flowering dates of the different collections
varied as much as 2 months.
Soils are described as individual mapping units and
technical profile descriptions are given for each soil.
Areas of activity included the point of removal, initially,
but with time the distance between removal and activity area
tended to increase. Results indicate that live-traps restricted
the normal activity patterns of some animals, and that neither
snap-traps nor live-traps capture all individuals in the area.
Nocturnal rodents were censused every 2 weeks on two, 1.69
ha (4.13 ac) live-trap grids. All nocturnal rodents except
Dipodomys merriami were removed from one of the grids. Effects
on the population biology of D. merriami were subsequently
analyzed. Removal caused no significant effect on home range.
Mean weight for both reproductively active and inactive males and
females was not significantly different following removal.
The emergence of 4 lovegrasses planted at 0.0, 0.5, 1.0, 1.5
and 2.0 cm depths in Pima silty clay loam, Sonoita silty clay
loam, and Comoro sandy loam soils were studied in a greenhouse.
Catalina boer lovegrass emergence was superior in all soils and
at all depths. Approximately 75% of the radicles of germinating
Lehmann and A-84 boer lovegrass seeds failed to penetrate the
surface of the three soils when surface sown. Lehmann lovegrass
seed planted below the surface failed to emerge in the three
soils.
Perennial grasses were seeded by drilling or broadcasting on
four mechanical and three herbicidal weed control and/or seedbed
preparation treatments at four semidesert grassland sites invaded
by creosotebush. The cultivars, "Cochise" Atherstone lovegrass
and "Catalina" Boer lovegrass, were initially established and
persisted in six of the eight plantings on disk plowed and disk
plowed plus contour furrowed seedbeds. These grasses were
established and persisted in two of the five plantings made in
creosotebush stands treated with herbicides. Grasses established
initially on two-way railed and land imprinted areas usually died
within 3 or 4 years.
Lehmann lovegrass was introduced into Arizona from South
Africa in 1932 and has since been sown throughout the
southwestern USA and northern Mexico. The species is well
adapted in southeastern Arizona where it has been sown on over
69,115 hectares and has spread by seed to an additional 76,040
hectares. Where lehmann lovegrass predominates and spreads,
surface soils are sandy, summer rainfall is greater than or equal
to 200 mm and winter temperatures rarely fall below 0 C. Factors
contributing to the spread of lehmann lovegrass include fire,
cattle grazing, and drought.
Describes the establishment and work function of various
experiment stations in the West.
A successful insurance practice would service the industry
by eliminating risk of drought and substituting a known
budgetable annual expense, by wiping out overstocking on insured
properties, by easing credit facilities through the use of
insurance as loan collateral and to lower interest rates, and by
contributing to increased security in the business enterprise
through its more efficient conduct, greater peace of mind, and
general stabilization of the ranch economy.
On 48 million acres in Arizona and New Mexico, or more than
a third of the total usable range in these states, as well as on
ranges in adjacent Texas, blue grama is the dominant forage
plant. Throughout this region, which is here loosely termed the
Southwest, blue grama is of primary importance on 13 national
forests, on other public lands, and on great areas of private
range.
There are three outstanding reasons for this superiority.
Blue grama provides excellent forage, is highly resistant to
grazing and drought, and is an effective soil binder. To a
considerable degree the welfare of the livestock industry in the
Southwest is dependent upon maintaining the dominance of blue
grama and the further protection and extension of present well-
established stands. For these reasons a widespread understanding
of the simple principles of utilization and management required
to maintain this high-grade forage and to make the most of its
soil-protective characteristics is highly desirable.
Preliminary recommendations regarding various control
methods of burroweed are discussed. Notes on the growth and
development are included.
A procedure is outlined for determination of total plant
density. A device called a densimeter is utilized to record
density on variable sized quadrats.
Preliminary findings showed most of the Santa Rita grasses,
along with a few shrubs, were grazed consistently during all
seasons of the year. Some grasses were preferred for short
periods on varied sites. California poppy and Indian wheat were
preferred whenever they were available. Shrub use was varied.
Grazing periods averaged between 7 and 8 hours during the summer
and winter and averaged about 9 hours in spring. Temperature and
forage condition influenced grazing behavior.
Three major factors, investment load per cow, proper
location of improvements, and adequacy of range improvements, are
essential to advance planning.
Results of an intensive rodent study showed that total
amount of vegetation eaten by the principal rodents amounted to
over 2.9 million pounds (1,450 tons) yearly, or the equivalent
consumption of 206 head of cattle yearlong. Rodents damaged
perennial grass roots, stalks, and seedheads, and they denuded
considerable areas around their dens. Some benefits from rodents
were realized.
Rains of less than 0.4 inch were largely ineffective insofar
as affecting the growth of range forage grasses, unless they
occurred for several days in succession and were preceded or
succeeded by rains of greater amounts. Summer growth was
expected after July 10. The growing season was about 9 weeks.
Approximately 93% of perennial grass yield was produced during
summer growth.
A 20-year assessment of the factors responsible for
increased financial returns revealed that conservative stocking
was the major influence. Other contributing factors included use
of good bulls, critical culling of breeding cows and careful
selection of heifer replacements.
In a 30-year assessment period, 13 factors were considered
as major factors affecting calf production. Condition of
breeding herd and size of breeding pastures were two major
factors.
Important factors involved in raising better cattle include:
(1) knowledge of latest research and methods of livestock
production, (2) livestock shows, and (3) ranch demonstrations of
new innovations. The main requirements for a good breeding herd
are outlined.
Improvement in grade of cattle is achievable by using better
bulls, providing adequate range forage yearlong, more critical
culling of breeding stock, and greater care in selection of
replacement heifers.
The answer to the death loss problem on the range is
adequate supervision that: (1) recognizes the need for a
conservative stocking rate, (2) is fully conscious of actual cost
of losses, (3) gets at the underlying causes of losses, and (4)
constantly strives to prevent and remedy them.
Modern methods of handling cattle are discussed.
When all operation expenses are considered, it cost an
average of $25.11 to produce an 8- or 9-month-old calf. The calf
crop averaged 82.7%, based on the number of cows in the breeding
herd. Cattle losses averaged 2.8% annually, while calf losses
were 2.9%, mostly from unknown causes. Range practices that
materially increased herd earnings were: (1) stocking on the
basis of sustained yield; (2) regular fall-winter sales of high-
grade calves; (3) reduction of carry-overs, horses, and aged
steers to the minimum; and (4) leaving an equivalent of at least
15% of the forage as a drought safety factor. Recent findings
have shown that a 20% reserve would be better. An average calf
crop of 44% was necessary to recover cash expenditures. A calf
crop greater than 56% was necessary for profits.
Range areas on which annual grasses and weeds are the
dominant vegetation should be grazed to obtain full use during
the summer and spring growing seasons. Areas where tanglehead,
cottongrass, or California threeawn are dominant can be grazed to
best advantage during the winter and late spring, since they
normally furnish a relatively greater amount of green feed at
these seasons than most other range grasses. Black grama areas
are chiefly valuable for grazing during the winter or spring and
do best when protected or subject to only light grazing during
the summer growing season. Mesquite and catclaw areas can be
grazed to best advantage during the winter.
Guajilla and range ratany are relished by cattle throughout
most of the year; however, where abundant they can be used to
best advantage during the spring when perennial grasses are dry
or largely grazed off. Most of the remaining common grasses and
small shrubs are grazed by cattle with equal relish throughout
the year and no particular advantage is to be gained by
attempting to use them at any specific season.
Lack of adequate salting may have its serious side since
cattle deprived of salt may attempt to satisfy their craving at a
dirt salt lick and may die as a result.
Long-term precipitation records are compared with recent
drought periods.
A comparative summary of the livestock business from 1910 to
1940 is provided.
Clipping treatments failed to simulate grazing by livestock,
but in spite of the differences, clipped quadrats can be of
immense value to actual grazing studies. Results can be obtained
at rather low costs to show the comparative maintenance, yield,
and quality of forage species under known varying intensities of
harvesting, with the effects of given amounts and character of
rainfall upon production. The method aided greatly in the
determination of correct utilization of range and pasture forage-
-a vital feature for the proper conservation of forage and
watershed resources. When used with perfected techniques and
judicious interpretation of results, it should prove to be even
more valuable than it has been in the past.
An adult male coyote captured on SRER was transported 48 km
away and observed to return to its capture site.
The data suggest that the use of the carcass area enlarged
home ranges of adult coyotes, but not those of pups and
yearlings. Immature coyotes appeared to be more dependent upon
the carrion than adults.
Home range areas averaged 2.1 (irregular polygon) and 29.3
(ellipse) square miles for adults and 2.6 (irregular polygon) and
3.7 (ellipse) for immature coyotes. Behavioral observations,
sightings of groups, and interactions were used to assess coyote
sociability. Average group size was 1.4 and several coyotes
formed temporary associations. A carcass area may have increased
home ranges of several adults and attracted coyotes from more
than 9 miles away. Pups may have been more dependent on the
carcass area for their food source.
Stomatal periodicities of Rothrock's grama and black grama
were found to be quite similar. Maximum stomatal opening
occurred between 2 p.m. and 4 p.m., and partial opening was
evident throughout the night. Cotton grass showed a close
correlation between stomatal periodicity and transpiration.
Plants clipped the previous summer made greater root growth
than above ground growth in the spring following clipping.
Clipping in both spring and spring-plus-summer resulted in a
temporary reduction in concentration of total nonstructural
carbohydrate in roots and above ground parts.
Range sites were identified using soil and vegetation data
from combinations of strata of two precipitation zones, three
groups of soils, and three levels of historical grazing use.
Bouteloua rothrockii and Trichachne californica were not useful
site indicators but were useful indicators in utilization
studies. Seven sites were identified from cluster analysis of
the soils and ordinated according to trends in permeability,
available water capacity, clay content, and thickness of surface
layers.
Rainfall and runoff data for a number of storm events on a
small watershed were analyzed. Double triangle unit hydrographs
were fitted to individual storm events. The differences in the
shapes of individual unit hydrographs were found to be small so
that they could be approximated by a single double triangle unit
hydrograph.
Minimum home ranges for 6 radio-tracked coyotes ranged in
size from 0.5 to 7.9 square miles. Females tended to occupy
larger areas than did males. Age distribution of 378 coyotes was
based on annual counts from canine teeth. Average age was 3.2
years. Of 273 known-sex coyotes, the ratio was 154 males: 119
females. Males tended to outlive females. Over 100 coyote
specimens were examined for parasites. Coyotes selected a
greater percentage of smaller mammals (35%) in their diet than
larger mammals (25.4%), birds (16.4%), vegetable matter (16.2%),
invertebrate (6.4%), or reptiles (0.1%).
The map delineates the major geological formations of the
area.
The Santa Rita Mountains consist of complex deformed
sedimentary, volcanic, and intrusive rocks of Precambrian through
Cenozoic ages. The Mesozoic rocks comprise 12 formations, have a
cumulative thickness of more than 30,000 feet, and represent
parts of at least the Triassic and Cretaceous Periods. These
rocks were almost all deposited subaerially, many of them in
basins associated with block faulting or volcanism or both, but
others were deposited in a more gently downwarped basin. The
rocks of the Late Cretaceous show signs of increasing orogenic
activity, and the deposition sequence described here ends at the
close of that period with the intrusion of large plutons.
Fossils from two of the formations and isotopic dates from six of
them augment the geologic field relations to provide a framework
for the interpretation of the geologic development of the area
through the Mesozoic.
A description of the stratigraphy and petrography of the
Cenozoic rocks and interpretation of their environments of
deposition or emplacement are discussed.
The major structural features are described and serve as a
discussion for understanding the regional tectonic development of
the area.
This study revealed that base metals, noble metals, and some
other rare metals have been mobilized and have accumulated
locally near certain rocks or structural features. Some
geochemical anomalies delineate known mining camps; others
suggest additional exploration targets. Several targets are
reviewed.
Prickly pear cladophylls and fruits were the major food
items in the palo verde-bursage cacti vegetative type, and
prickly pear and century plants were the major food items in the
desert-grassland type. Century plants, tubers, and acorns were
important in the oak-grassland types. Succulent forbs were
preferred. Seasonal feeding activity patterns were noted.
Significant competition between livestock and peccaries was not
noted.
Prickly pear pads and fruits were the major food items in
the palo verde-bursage-cacti vegetative type. Prickly pear and
century plants were the most important foods in the desert-
grassland vegetative type. Century plants and tubers made up the
bulk of the peccaries' diet in the oak-grassland vegetative type.
Cactus fruits, beans, berries, and annual forbs provided
valuable seasonal supplements in the peccaries' diet.
Lehmann lovegrass responded to moisture conditions by
increasing or decreasing shoot growth. Grazing treatments
stimulated new shoot and root growth. Neither grazing treatment
had detrimental effects compared to no grazing. The total
accumulated carbohydrate reserves in roots showed quick response
of lehmann lovegrass to grazing and moisture conditions. Rolled
dry green leaves were noted during dry periods, a characteristic
of the plant that allows moisture retention by reducing
transpiration during water stress.
Immediately after a burn there was not a significant change
in runoff and erosion; therefore, vegetation cover by itself was
concluded not to be a dominant factor in controlling surface
runoff and erosion. The increase found in surface runoff and
sediment production from the burn plots was not significantly
greater than the natural variability for the locations or
seasons. Significantly higher surface runoff and sediment
production was measured in the fall season compared to the spring
at one location.
Results indicated that initial subdivision of the study area
into two subcommunities using 1:6000 scale imagery were in fact
valid and that a quantitative measure of the differences is
possible using 1:600 scale imagery. The imagery techniques,
using approximately one-third as many sample units, adequately
detected crown cover differences nearly as well as more intensive
ground sampling.
No differences were observed among age distributions,
weights, ovulation rates, and litter sizes of coyotes from three
study areas. Visitation rates of coyotes, lagomorphs, and small
mammals fluctuated greatly. Distribution of coyote and lagomorph
visits along a scent station line remained unchanged after the
summer of 1976, but small mammal visitation increased. The
breeding rate remain unchanged after the carrion supply ended.
Perennial grasses and mesquite were determined to affect the
growth and propagation of cholla. Increased percent ground cover
of perennial grasses reduces the total number of cholla plants
per acre. An inverse correlation exists between the total number
of cholla plants per acre and crown cover of mesquite, while a
positive correlation exists between the percentage of young
cholla plants and crown cover of mesquite. Cholla crown cover
has doubled during the last 20 years on some local areas.
A microscope point method was used to develop weight
prediction equations for plant species in masticated forage
samples. With 400 microscope points, the average weight of a
species was estimated within 5% of the mean at a 90% level of
probability when the species constituted 30-60% of the sample
weight.
Rumen-fistulated steers were employed to study the botanical
composition of the diet on a desert grassland range. Botanical
composition of the major plant species in the diet was determined
on a qualitative and quantitative basis using a microscope point
technique. The botanical composition of the diet changed greatly
with time of year and was considerably different quantitatively
compared to the available forage. Crude protein content of the
rumen samples was considerably greater than the protein content
of the whole hand-clipped major plant species identified in the
rumen samples.
Refer to Galt et al. 1966.
Dietary composition of plant groups consisted of 67-97%
grasses, 0-4% forbs, and trace to 33% shrubs. Species
composition of diets varied by seasons and among animals. Plant
preference was not necessarily related to plant availability.
Composition of diets was markedly different from composition of
pastures. Black grama averaged only 3% of diets but comprised
about one-third of herbage production. Arizona cottontop, which
averaged 20% of herbage on pastures, was the most consistently
selected species, averaging 34% of the diet. Seasonal preference
was shown for certain grasses such as rothrock grama in spring
and bush muhly in winter. Highest preference for shrub species
was shown in winter and early summer. Overall dietary
composition between pastures was much the same, but average
herbage production for a 2-year period was 347 kg/ha greater
where mesquite had been controlled. Leaves comprised the major
plant part of steer diets on both pastures. Leaf content of
diets increased from winter to summer while stems decreased for
the same periods.
The botanical composition of the diet varied both
qualitatively and quantitatively with the time of the year. A
great difference existed between the botanical composition of the
pasture and rumen samples. The ocular estimate was only a
general estimate of the animals' diet and the microscope point
method estimated botanical composition of the diet with a
reliable degree of accuracy.
Species composition of the steer diets was different from
composition of the available species. Arizona cottontop was the
most consistently selected and predominant species in the diets.
Shrubs were selected primarily in spring and summer.
Selectivity was shown for certain plant parts. Apparent
digestibility of dry matter, acid-detergent fiber, crude protein,
and gross energy increased during the summer. Forage intake was
significantly higher during summer. Total crude protein content
was adequate for maintenance most seasons except winter.
Forage biomass, nutrient value, botanical composition, and
ground cover were greater in the growing season than in the
dormant season. Moderate and heavy grazed pastures had lower
plant parameters than very heavy grazed, except for forage
biomass and lehmann lovegrass proportion, forage fiber and ground
cover. Slopes and washes had a higher forage nutrient content
and lower biomass and ground cover than uplands. Lehmann
lovegrass was more abundant on the uplands and in the washes than
on the slopes and the inverse was true for native species.
Understory forages contained greater nutrients and forbs than
open forages and the inverse occurred for shrubs and ground
cover.
Thirty-seven different ant species were found at three
sites: 18 at Silverbell, 21 at Santa Rita treated, and 33 at
Santa Rita control. The qualitative and quantitative analyses of
the ant fauna showed that these three sites were differentiated
by a dense community of Pheidole xerophila tucsonica and
Pogonomyrmex pima at Silverbell; by a significant community of
Pheidole xerophila tucsonica, Pheidole pilifera artemisia,
Iridomyrmex pruinosum analis, Pheidole spadonia and Pogonomyrmex
desertorum at the Santa Rita treated site; and by an elevated
community of Crematogaster coarctata vermiculata and Forelius
foetidus at the Santa Rita control site. The sites are also
differentiated by the number of nests present per hectare:
Silverbell, 492; Santa Rita treated, 1926; and Santa Rita
control, 1753. By an indirect method, used for the first time,
the biomass of six dominant species at Silverbell was estimated.
The total biomass of the workers is 586 g, equivalent to 3696
kcal/ha for 1,600,000 workers. The biomass is about 105 g for
Veromessor pergandei, 1 g for Pheidole xerophila tucsonica, 159 g
for Novomessor cockerelli, and 305 g for Pogonomyrmex rugosus.
The diversity and abundance of reptiles were studied in
three vegetation types on the Santa Rita Experimental Range,
Arizona. Total reptile sightings were greatest in undisturbed
mesquite and mesquite with irregularly shaped clearings. No
zebra-tailed lizards (Callisaurus draconoides) or desert spiny
lizards (Sceloporus magister) were seen, and significantly fewer
western whiptails (Cnemidophorus tigris) were in the mesquite-
free area. Only the Sonora spotted whiptail (Cnemidophorus
sonorae) was significantly more abundant in the mesquite-free
area than in the undisturbed mesquite. In an effort to increase
grass production for cattle in mesquite grasslands, it is
preferable to clear irregularly shaped areas rather than to
attempt total mesquite removal if reptiles are to be considered.
Mesquite with clearings contained significantly more black-
tailed jackrabbits, antelope jackrabbits, Gambel's quail, western
whiptails, and all reptiles sighted than mesquite-free areas.
The model is a continuous, deterministic computer simulation
that predicts the soil moisture regime of the soil profile. This
in turn is used to calculate a stress index value. Annual forage
yield is then estimated as a function of stress index values.
Field tests between actual data and simulated yield data resulted
in .1 kg/hectare average annual difference.
Arizona cottontop (Digitaria californica (Benthe.) Henr.)
has been replaced by lehmann lovegrass (Eragrostis lehmanniana
Nees) on southeastern Arizona rangelands. This research was
conducted to investigate the effects of defoliation on their
physiological and morphological characteristics. Plants were
defoliated by clipping at a 5-cm height and measurements made
every 14 days. Clipping did not affect apparent photosynthesis
or dark respiration during the 56-day study; however, defoliation
reduced above-ground biomass and the nitrogen and phosphorus
content in both species. Root biomass of clipped Arizona
cottontop and lehmann lovegrass declined 50% and 28%,
respectively. Nitrogen and phosphorous concentrations in Arizona
cottontop roots declined 42% and 61%, and 32% and 27% in lehmann
lovegrass, respectively. The small decline in lehmann lovegrass
root production and the major change in Arizona cottontop root
biomass after defoliation may partially explain why lehmann
lovegrass has been replacing Arizona cottontop.
Broadcast seeding of native forage grasses followed by light
harrowing to cover the seed is practical on small areas where the
top soil is still in place. Maintenance of sufficient litter
cover is an essential objective in proper range management.
Light grazing is needed until plants become properly established.
Tests were conducted to determine the effects of litter on
the germination of grass seeds and survival of seedlings.
Preliminary observation showed grasses fail to germinate on bare
ground, despite an abundance of seed. Excellent stands of
seedlings covered area mulched with barley straw.
Topsoil material obtained from grassy areas was spread to a
depth of about 3 inches on four small plots in a denuded area.
One and a half years later, plots were covered with seedlings of
annuals and perennial grasses.
Preliminary observations revealed greater seedling
germination and establishment on disked and mulched plots than on
disked-only plots.
Germination tests indicate the seed is better than 50%
viable. Seed will germinate under extremely adverse moisture and
soil conditions; and the seedlings, once started, are especially
drought tolerant. Seed dispersal is good. Tanglehead thrives
best at altitudes of 4,000 to 5,000 feet but grows well as low as
2,500 feet.
The germination of grass seeds on deteriorated barren soils
can be greatly increased through the application of artificial
litter in the form of straw or hay. The establishment of
seedlings of important forage grasses was practically prohibited
where some form of litter was lacking.
The study determined the effect of different frequencies of
irrigation and varying intensities of competition for light and
soil moisture upon the development of shoots and roots, storage
of starch, and recovery after drought of tanglehead seedlings.
Maximum development of shoots and roots occurred under most
frequent irrigation and least intense competition, whereas
shoot/root ratios were found to be inversely proportional to
these two factors. Amount of starch storage showed no consistent
relation to treatments. Soil moisture was attributed to be the
major controlling factor in development of plants.
2. Alonso, Ramon Claveran. 1967. Desert grassland mesquite and
fire. Tucson, AZ: University of Arizona, Department of
Watershed Management. 182 p. Ph.D. dissertation.
3. Anderson, Anders H.; Anderson, Anne. 1959. Life history of
the cactus wren. Part II: The beginning of nesting.
Condor. 61(3): 186-205.
4. Anderson, Darwin; Hamilton, Louis P.; Reynolds, Hudson G.;
Humphrey, Robert R. 1953. Reseeding desert grassland
ranges in southern Arizona. Bulletin 249. Tucson, AZ:
University of Arizona, Agricultural Experiment Station. 31 p.
5. Anderson, Darwin, Hamilton, Louis P.; Reynolds, Hudson G.;
Humphrey, Robert R. 1957. Reseeding desert grassland
ranges in southern Arizona. Bulletin 249. Tucson, AZ:
University of Arizona, Agricultural Experiment Station.
[Originally issued 1937 by Agriculture Experiment Station,
Reseeding desert grassland ranges in southern Arizona.] 31 p.
6. Arizona Game and Fish Department. 1976. Hematology of deer.
Final report: Federal Aid in Wildlife Restoration Project W-78-R,
Work Plan 3, Job 4. 9 p. Phoenix.
7. Arnold, J. F. 1946. Plot studies on the effects of
nitrates on a southwestern range. Tucson, AZ:
University of Arizona. 66 p. M.S. thesis.
8. Arnold, Joseph F. 1942. Forage consumption and
preferences of experimentally fed Arizona and antelope
jackrabbits. Technical Bulletin 98. Tucson, AZ:
University of Arizona, Agricultural Experiment Station. 86 p.
9. Arnold, Joseph F.; Reynolds, Hudson G. 1943. Droppings
of Arizona and antelope jackrabbits and the "pellet census."
Journal of Wildlife Management. 7(3): 322-327.
10. Barr, George V. 1955. A comparison of the survival over a
twenty-year period of several native Arizona grasses.
Tucson, AZ: University of Arizona. 34 p. M.S. thesis.
11. Barth, Richard Charles. 1975. Spatial distribution of
carbon and nitrogen in some desert shrub ecosystems. Tucson, AZ:
School of Renewable Natural Resources, University of Arizona.
143 p. Ph.D. dissertation.
12. Bashford, Leonard Leroy. 1966. An automatic animal weight
recording system. Tucson, AZ: School of Renewable Natural
Resources, University of Arizona. 46 p. M.S. thesis.
13. Beal, Raymond H.; Carter, Fairie Lyn. 1968. Initial
soil penetration by insecticide emulsions used for
subterranean termite control. Journal of Economic
Entomology. 61(2): 380-383.
14. Bentley, R. Gordon, Jr. 1964. The effects of three
moisture levels applied to lehmann lovegrass grown on a
fertilized desert grassland soil. Tucson, AZ: University
of Arizona. 35 p. M.S. thesis.
15. Blair, Byron O. 1950. Recent results of basic
physiological studies of mesquite in the Southwest.
Western Weed Control Conference Proceedings. 12:104.
17. Blair, Byron O.; Fuller, W.H. 1952. Translocation of
2,4-dichloro-5-Iodo-phenoxyacetic acid in velvet mesquite
seedlings. Botanical Gazette. 113(3): 368-372.
18. Blair, Byron O.; Glendening, George E. 1953. Intake
and movement of herbicides injected into mesquite.
Botanical Gazette. 115(2): 173-179.
19. Blake, Steven Bruce. 1980. Prediction of forage yield from
simulated soil moisture deficits. Tucson, AZ: University of
Arizona. 167 p. M.S. thesis.
20. Blydenstein, John. 1966. Root systems of four desert
grassland species on grazed and protected sites. Journal of
Range Management. 19(2): 93-95.
21. Bohning, John W. 1956. What will burning do for your
semidesert range? Arizona Stockman. 22(11): 14-15.
22. Bohning, John W. 1958a. Salting for better livestock
distribution. Arizona Cattlelog. 13(5): 60-61.
23. Bohning, John W. 1958b. Who can afford to haul water? The
American Hereford Journal. 49(5): 656-657.
24. Bohning, John W.; Martin, S. Clark. 1956. One rancher's
experience--in the grassland range of southern Arizona.
Journal of Range Management. 9: 258-260.
25. Brown, Albert L. 1950. Shrub invasion of southern
Arizona desert grassland. Journal of Range Management.
3(2): 172-177.
26. Cable, Dwight R. 1959. Some effects of fire and drought on
semidesert grasses and shrubs. Tucson, AZ: University of
Arizona. 27 p. M.S. thesis.
27. Cable, Dwight R. 1961. Small velvet mesquite seedlings
survive burning. Journal of Range Management. 14(3): 160-161.
28. Cable, Dwight R. 1965. Damage to mesquite, Lehmann
lovegrass, and black grama by a hot June fire.
Journal of Range Management. 18(6): 326-329.
29. Cable, Dwight R. 1966. Competition between burroweed and
annual and perennial grasses for soil moisture. In: Proceedings
of American Forage and Grassland Council; 1966 February 1-4; New
Orleans, LA: 11-27.
30. Cable, Dwight R. 1967. Fire effects on semidesert grasses
and shrubs. Journal of Range Management. 20(3): 170-176.
31. Cable, Dwight R. 1969a. Competition in the semidesert
grass-shrub type as influenced by root systems, growth habits,
and soil moisture extraction. Ecology. 50(1): 27-38.
32. Cable, Dwight R. 1969b. Soil temperature variations on a
semidesert habitat in southern Arizona. Research Note RM-
128. Fort Collins, CO: U.S. Department of Agriculture,
Forest Service, Rocky Mountain Forest and Range Experiment
Station. 4 p.
33. Cable, Dwight R. 1971a. Growth and development of
Arizona cottontop (Trichachne californica [Benth]
Chase). Botanical Gazette. 132(2): 119-145.
34. Cable, Dwight R. 1971b. Lehmann lovegrass on the Santa
Rita Experimental Range, 1937-1968. Journal of Range
Management. 24(1): 17-21.
35. Cable, Dwight R. 1972a. Fire effects in southwestern
semidesert grass-shrub communities. In: Proceedings
Annual Tall Timbers Fire Ecology Conference;
1972 June 8-9; 109-127.
36. Cable, Dwight R. 1972b. Fourwing saltbush revegetation
trials in southern Arizona. Journal of Range Management.
25(2): 150-153.
37. Cable, Dwight R. 1972c. Seasonal use of soil moisture by
mature velvet mesquite (Prosopis juliflora var. velutina).
US/IBP Desert Biome Research Memorandum 72-18. Logan, UT:
Ecology Center, Utah State University. 4 p.
Soil moisture measurements were taken with a neutron probe
on 30 dates between July 10 and December 31, 1971, to determine
the pattern of soil moisture use by 4 mature velvet mesquite
trees (Prosopis juliflora var. velutina) both in time and within
a soil mass 6 m deep and extending laterally 20 m from the tree
trunk. Data were submitted to the Biome data bank, but no
summaries were prepared.
38. Cable, Dwight R. 1974. Seasonal use of soil moisture by
mature velvet mesquite (Prosopis juliflora var.
velutina). US/IBP Desert Biome Research Memorandum 74-18.
Logan, UT: Ecology Center, Utah State University. 10 p.
39. Cable, Dwight R. 1975. Influence of precipitation on
perennial grass production in the semidesert southwest. Ecology.
56: 981-986.
40. Cable, Dwight R. 1976. Twenty years of changes in grass
production following mesquite control and reseeding.
Journal of Range Management. 29(4): 286-289.
41. Cable, Dwight R. 1977. Seasonal use of soil water by
mature velvet mesquite. Journal of Range Management. 30(1): 4-
11.
42. Cable, Dwight R. 1979. Ecology of Arizona cottontop.
Research Paper RM-209. Fort Collins, CO: U.S. Department of
Agriculture, Forest Service, Rocky Mountain Forest and Range
Experiment Station. 21 p.
This paper summarizes what is now known about the ecology
and management of Arizona cottontop (Trichachne californica), a
palatable, drought-hardy, perennial grass that thrives under
moderate grazing on semidesert ranges of the Southwest.
Perennial culms that produce axillary shoots and have favorable
response to grazing, long life, and ability to grow both on warm
and cool season moisture are valuable attributes of this species.
43. Cable, Dwight R. 1980. Seasonal patterns of soil water
recharge and extraction on semidesert ranges. Journal of
Range Management. 22(1): 9-15.
44. Cable, Dwight R.; Bohning, John W. 1959. Changes in
grazing use and herbage moisture content of three exotic
lovegrasses and some native grasses. Journal of Range
Management. 12(4): 200-203.
45. Cable, Dwight R.; Martin, S. Clark. 1964. Forage
production and stocking rates on southern Arizona ranges can
be improved. Research Note RM-30. Fort Collins, CO: U.S.
Department of Agriculture, Forest Service, Rocky Mountain
Forest and Range Experiment Station. 11 p.
46. Cable, Dwight R.; Martin, S. Clark. 1975. Vegetation
responses to grazing, rainfall, site condition, and mesquite
control on semidesert range. Research Paper RM-149. Fort
Collins, CO: U.S. Department of Agriculture, Forest Service,
Rocky Mountain Forest and Range Experiment Station. 24 p.
47. Cable, Dwight R.; Shumway, R. Phil. 1966. Crude protein in
rumen contents and in forage. Journal of Range Management.
19(3): 124-128.
48. Cable, Dwight R.; Tschirley, Fred H. 1961. Responses
of native and introduced grasses following aerial spraying
of velvet mesquite in southern Arizona. Journal of Range
Management. 14(3): 155-159.
49. Calder, W. A. 1968. The diurnal activity of the
roadrunner (Ceococcyx californianus). Condor. 70(1):
84-85.
Findings suggest the roadrunner relies upon behavioral and
ecological means rather than special physiological capacities for
surviving desert conditions.
50. Calder, William A. 1968. There really is a roadrunner.
Natural History. 77: 50-55.
51. Calvo, Susanna S. 1980. Scarps on the Madera Canyon
alluvial fan: evidence for quaternary tectonism? In:
Geosciences Daze, Eighth Annual Colloquium. 1980 March 5-7;
Tucson, AZ: Department of Geosciences, University of
Arizona: 5.
52. Canfield, R. H. 1942a. The relative grazing preference of
cattle for the common semidesert grasses in southern
Arizona. Research Note RM-102. Tucson, AZ: U.S.
Department of Agriculture, Forest Service, Southwestern
Forest and Range Experiment Station. 3 p.
53. Canfield, R. H. 1942b. Sampling ranges by the line
interception method: plant cover, composition, density,
degree of forage use. Research Report 4. Tucson, AZ: U.S.
Department of Agriculture, Forest Service, Southwestern
Forest and Range Experiment Station. 28 p.
54. Canfield, R. H. 1942c. A short-cut method for estimating
grazing use. Research Note 99. Tucson, AZ: U.S.
Department of Agriculture, Forest Service, Southwestern
Forest and Range Experiment Station. 5 p.
55. Canfield, R. H. 1943. What is conservation grazing? A
question every ranchman should be vitally interested in. The
Cattleman. 30: 16, 18.
56. Canfield, R. H. 1944a. Measurement of grazing use by the
line interception method. Journal of Forestry. 42(3): 192-194.
Field experience in the Southwest has demonstrated the
suitability of the line interception method for combining the
measurement of utilization with plant density and composition
estimates. It includes the advantages of actual measurement and
random sampling. Moreover, the data obtained lend themselves
readily to statistical analysis. The method operates equally
well in sampling both large and small pastures.
57. Canfield, R. H. 1944b. A short-cut method for checking
degree of forage utilization. Journal of Forestry. 42(4):
192-194.
58. Canfield, R. H. 1948. Perennial grass composition as an
indicator of condition of southwestern mixed grass ranges.
Ecology. 29(2): 190-204.
59. Canfield, R. H. 1957. Reproduction and life span of some
perennial grasses of southern Arizona. Journal of Range
Management. 10(5): 199-203.
60. Caraher, David Luther. 1970. Effects of longtime
livestock exclusion versus grazing on the desert
grassland of Arizona. Tucson, AZ: University of Arizona.
45 p. M.S. thesis.
61. Carr, Richard Vance. 1972. The tergal gland and
courtship behavior in the termites Pterotermes
occidentis, Marginitermes hubbardi, and Paraneotermes
simplicicornis (Isoptera: Kalotermitidae). Tucson, AZ:
Department of Entomology, University of Arizona. 93 p.
Ph.D. dissertation.
62. Carter, Fairie Lyn; Stringer, Charles A. 1970a.
Residues and degradation products of technical
heptachlor in various soil types. Journal of Economic
Entomology. 63(2): 625-628.
63. Carter, Fairie Lyn; Stringer, Charles A. 1970b. Soil
moisture and soil type influence initial penetration by
organochlorine insecticides. Bulletin of Environmental
Contamination and Toxicology. 5(5): 422-428.
64. Carter, Fairie Lyn; Stringer, Charles A. 1971. Soil
persistence of termite insecticides. Pest Control. 39(2):
13-14, 16, 18, 22, 29.
65. Carter, Fairie Lyn; Stringer, Charles A.; Beal, Raymond H.
1970. Penetration and persistence of soil insecticides used for
termite control. Pest Control. 38(10): 18-22.
66. Cassady, John T.; Glendening, George E. 1940.
Revegetating semidesert range lands in the southwest.
Forestry Publication No. 8. Washington, DC: U.S. Federal
Security Agency, Civilian Conservation Corps. 21 p.
67. Clary, Warren P. 1975. Ecotypic adaptation in Sitanion
hystrix. Ecology. 56: 1407-1415.
68. Clemmons, Stan; Wheeler, L.D. 1970. Soils report:
Santa Rita Experimental Range, Coronado National Forest.
Albuquerque, NM: U.S. Department of Agriculture, Forest
Service, Southwestern Region. 41 p.
69. Courtney, Mark William. 1971. Effects of removal on
movements within populations of nocturnal desert rodents.
Tucson, AZ: University of Arizona. 32 p. M.S. thesis.
70. Courtney, Mark William. 1983. Effects of reduced
interspecific interactions on population dynamics in
merriam's kangaroo rat, Dipodomys merriami. Tucson, AZ:
University of Arizona. 73 p. Ph.D. dissertation.
71. Cox, Jerry R.; Martin-R, Martha H. 1984. Effects of
planting depth and soil texture on the emergence of four
lovegrasses. Journal of Range Management. 37(3): 204-205.
72. Cox, Jerry R.; Martin-R., Martha H.; Ibarra-F., Fernando A.;
Morton, Howard L. 1986. Establishment of range grasses on
various seedbeds at creosotebush (Larrea tridentata) sites
in Arizona, U.S.A., and Chihuahua, Mexico. Journal of Range
Management. 39(6): 540-546.
73. Cox, J. R.; Roundy, G.B. 1986. Influence of climactic and
edaphic factors on the distribution of Eragrostis
lehmanniana Nees in Arizona, USA. Journal Grassland Society
of South Africa. 3(1): 25-29.
74. Crafts, Edward C. 1938a. Experimental ranges and other
range research centers of the Forest Service. Tucson, AZ:
U.S. Department of Agriculture, Forest Service, Southwestern
Forest and Range Experiment Station. 15 p.
75. Crafts, Edward C. 1938b. Height-volume distribution in
range grasses. Journal of Forestry. 36(12): 1182-1185.
There are 137 million acres of usable range in Arizona and
New Mexico, and livestock production is an outstanding industry
in the Southwest. Basic resources of this industry are the soils
and the vegetation they support. Continued production of range
grasses is, in a large measure, dependent on forage utilization.
The importance of knowing what constitutes proper use of a given
kind of grass and of having an accurate method of measuring its
utilization becomes evident when one realizes that a 10%
variation in the use of the herbage volume may result in
continued productivity or gradual death of the plant.
76. Crafts, Edward C. 1941. A plan for insurance against
drought on the range lands of Arizona and New Mexico. Ann Arbor,
MI: School of Forestry and Conservation, University of Michigan.
166 p. Ph.D. dissertation.
77. Crafts, Edward C.; Glendening, George E. 1942. How to
graze blue grama on southwestern ranges. Leaflet 215.
Washington, DC: U.S. Department of Agriculture. 8 p.
78. Cribbs, W. J. 1938. Burroweed control on southwestern
ranges. Arizona Stockman. Jan. 4-5.
79. Culley, Matt. 1937. How to get sustained forage
production in grazing semidesert mixed grass ranges.
Western Livestock Journal. 15(23): 5-6.
Results of a 9-year study showed that: (1) on the average,
most of the common semidesert range grasses in southern Arizona
can be grazed safely within 2 inches of the ground; (2) black
grama, an exception to this rule, cannot be grazed closer than 3
inches above the ground; (3) moderate-heavy grazing should be
limited during drought years; (4) deficient rainfall coupled with
continuous close grazing results in very large reductions in both
stand and yield of forage; and (5) sustained or proper grazing
capacity should approximate 20% below the capacity of the range
under forage conditions of the average year.
80. Culley, Matt. 1938a. Densimeter, an instrument for
measuring the density of ground cover. Ecology. 19(4):
588-590.
81. Culley, Matt. 1938b. Grazing habits of range cattle. The
Cattleman. 24: 19-23. [Also in The Hereford Journal. January:
18,19,22.].
This study reports on the grazing habits of cattle, their
forage preferences, diurnal and nocturnal activities, factors
affecting distribution, and factors that influence grazing
behavior.
82. Culley, Matt. 1938c. Grazing habits of range cattle.
American Cattle Producer. 20(1): 3, 4, 16, 17.
83. Culley, Matt. 1938d. Planning for range improvements.
American Cattle Producer. 20(3): 3-4. [Also in Western Livestock
Journal. August 16(34):8. New Mexico Stockman. August: 8-9.].
84. Culley, Matt. 1939a. The decagon for vegetation
studies. Journal of Forestry. 37(6): 492-493.
The decagon is a 10 square-foot sampling quadrat divided
into 10 equal triangular segments. Density estimates of each
segment are calculated separately. The statistical advantage is
that each plot provides 10 samples instead of one. This
technique is best suited for research where a certain degree of
accuracy must be observed.
85. Culley, Matt. 1939b. Rodents or cattle? Western
Livestock Journal. 17(19): 30-31.
86. Culley, Matt. 1943a. Grass grows in summer or not at all.
American Hereford Journal. 34(9): 8, 10.
87. Culley, Matt. 1943b. Proper stocking pays dividends.
Western Livestock Journal. 28(1): 7.
88. Culley, Matt. 1946a. Factors affecting range calf crop.
Arizona Stockman. 12(10): 30-37.
89. Culley, Matt. 1946b. Good range cattle. Arizona
Cattlelog. 1(10): 3-6; and 1(11): 12-14.
90. Culley, Matt. 1946c. Quality cattle for profit.
American Hereford Journal. 37(11): 8-9, 168-169.
91. Culley, Matt. 1947. It pays to be loss conscious. The
Cattleman. 34(7): 25-26, 52, 55.
92. Culley, Matt. 1948. Modern business methods in handling
range cattle. Arizona Stockman. 14(4): 13, 26-27.
93. Culley, Matt J. 1937a. An economic study of cattle
business on a southwestern semidesert range. Circular 448.
Washington, DC: U.S. Department of Agriculture. 24 p.
94. Culley, Matt J. 1937b. Grazing habits of range cattle.
Research Note 21. Tucson, AZ: U.S. Department of
Agriculture, Forest Service, Southwestern Forest and Range
Experiment Station. 4 p.
95. Culley, Matt J. 1941. Does it rain less now than in the
old days? Western Livestock Journal. 19(44): 5, 78.
96. Culley, Matt J. 1942. Thirty years ago and now in
Arizona cattledom. Western Livestock Journal. 28(2): 43.
97. Culley, Matt J.; Campbell, R.S.; Canfield, R.H. 1933.
Values and limitations of clipped quadrats. Ecology. 14(1):
35-39.
98. Danner, Dennis A.; Fisher, Alan R. 1977. Evidence of
homing by a coyote (Canis latrans). Journal of Mammalogy.
58(2): 245.
99. Danner, Dennis A.; Smith, Norman S. 1980. Coyote home
range, movement and relative abundance near a cattle feed
yard. Journal of Wildlife Management. 44(2): 484-487.
100. Danner, Dennis Alan. 1976. Coyote home range, social
organization, and post visitation. Tucson, AZ: University of
Arizona. 86 p. M.S. thesis.
101. Darrow, Robert A. 1935. Study of the transpiration rates
of several desert grasses and shrubs as related to
environmental conditions and stomatal periodicity. Tucson,
AZ: University of Arizona. 116 p. M.S. thesis.
102. de Andrade, Ivo Francisco. 1979. Growth response of
sideoats grama to seasonal herbage removal and competition from
adjacent vegetation. Tucson, AZ: School of Renewable Natural
Resources, University of Arizona. 90 p. Ph.D. dissertation.
103. de Oliveira, Jose Gerardo Beserra. 1979.
Characterization of range sites. Tucson, AZ: School of
Renewable Natural Resources, University of Arizona. 105 p.
Ph.D. dissertation.
104. Diskin, M. H.; Lane, L. J. 1976. Application of a double
triangle unit hydrograph to a small semi-arid watershed.
Journal of the Arizona Academy of Science. Abstract 309,
Proceedings supplement: 108.
105. Drewek, John, Jr. 1980. Behavior, population structure,
parasitism, and other aspects of coyote ecology in southern
Arizona. Tucson, AZ: Department of Biological Sciences,
University of Arizona. 277 p. Ph.D. dissertation.
106. Drewes, Harald. 1971a. Geologic map of the Sahuarita
quadrangle, southeast of Tucson, Pima County, Arizona.
Miscellaneous Geological Investigation Map No. I-613, scale
1:48,000. Washington, DC: U.S. Department of the Interior,
Geological Survey.
107. Drewes, Harald. 1971b. Mesozoic stratigraphy of the Santa
Rita Mountains, southeast of Tucson, Arizona. Professional Paper
658-C. Washington, DC: U.S. Department of the Interior,
Geological Survey. 81 p.
108. Drewes, Harald. 1972a. Cenozoic rocks of the Santa Rita
Mountains southeast of Tucson, Arizona. Professional Paper
No. 746. Washington, DC: U.S. Department of the Interior,
Geological Survey. 66 p.
109. Drewes, Harald. 1972b. Structural geology of the Santa
Rita Mountains, southeast of Tucson, Arizona. Professional
Paper No. 748. Washington DC: U.S. Department of the
Interior, Geological Survey. 35 p.
110. Drewes, Harald. 1973. Geochemical reconnaissance of the
Santa Rita Mountains, southeast of Tucson, Arizona. Bulletin No.
1365. Washington, DC: U.S. Department of the Interior,
Geological Survey. 67 p.
111. Eddy, Thomas A. 1959. Foods of the collared peccary,
Pecari tajacu sonoriensis (Mearns), in southern Arizona.
Tucson, AZ: Wildlife Management Department, University of
Arizona. 102 p. M.S. thesis.
112. Eddy, Thomas A. 1961. Foods and feeding patterns of the
collared peccary in southern Arizona. Journal of Wildlife
Management. 25: 248-259.
113. Elmi, Ahmed Abdi. 1981. Phenology, root growth and root
carbohydrates of Lehmann lovegrass (Eragrostis lehmanniana)
in response to grazing. Tucson, AZ: University of Arizona.
58 p. M.S. thesis.
114. Emmerich, William E.; Cox, Jerry R. 1992. Hydrologic
characteristics immediately after seasonal burning on
introduced and native grasslands. Journal of Range
Management. 45(5): 4-476.
115. Fish, Ernest B.; Smith, Edwin L. 1973. Use of remote
sensing for vegetation inventories in a desert shrub community.
Progressive Agriculture in Arizona. 25(3): 3-5.
116. Fisher, Alan Raymond. 1980. Influence of an abundant
supply of carrion on population parameters of the coyote.
Tucson, AZ: School of Renewable Natural Resources, University of
Arizona. 94 p. Ph.D. dissertation.
117. Follett, Edson Roy. 1962. The increase of cholla
(Opuntia fulgida Engelm.) in relation to associated
specieson a desert grassland range of southern Arizona.
Tucson, AZ: University of Arizona. 28 p. M.S. thesis.
118. Galt, H. D.; Ogden, Phil R.; Ehrenreich, J. H.; Theurer,
Brent; Martin, S. Clark. 1968. Estimating botanical
composition of forage samples from fistulated steers by a
microscope point method. Journal of Range Management.
21(6): 397-401.
119. Galt, H. D.; Theurer, Brent; Ehrenreich, J. H.; Hale, W.
H.; Martin, S. Clark. 1966. Botanical composition of the diet
of steers grazing a desert grassland range. Proceedings of the
Western Section of the American Society of Animal Science. 17:
397-401.
120. Galt, H. D.; Theurer, Brent; Ehrenreich, J. H.; Hale, W.
H.; Martin, S. Clark. 1969. Botanical composition of diet of
steers grazing a desert grassland range. Journal of Range
Management. 22(1): 14-19.
121. Galt, H. D.; Theurer, Brent; Martin, S. Clark. 1982.
Botanical composition of steer diets on mesquite and
mesquite-free desert grassland. Journal of Range
Management. 35(3): 320-325.
122. Galt, Henry D. 1966. The botanical composition of steer
diet on a semidesert range. Tucson, AZ: University of
Arizona. 99 p. M.S. thesis.
123. Galt, Henry Deloss. 1972. Relationship of the botanical
composition of steer diet to digestibility and forage intake
on a desert grassland. Tucson, AZ: Department of Watershed
Management, University of Arizona. 234 p. Ph.D.
dissertation.
124. Gamougoun, Ngartoina Dedjir. 1987. Cattle grazing
behavior and range plant dynamics in southern Arizona.
Tucson, AZ: Department of Nutritional Sciences, University
of Arizona. 235 p. Ph.D. dissertation.
125. Gaspar, C.; Werner, F. G. 1976. The ants of Arizona: An
ecological study of ants in the Sonoran Desert. US/IBPDesert
Biome Research Memorandum 73-50. Logan, UT: Ecology Center, Utah
State University. 14 p.
126. Germano, David J.; Hungerford, C. Roger. 1981. Reptile
population changes with manipulation of
Sonoran Desert shrub. Great Basin
Naturalist. 41(1): 129-138.
127. Germano, David Joseph. 1978. Responses of selected
wildlife to mesquite removal in desert grassland. Tucson,
AZ: University of Arizona. 60 pp. M.S. thesis.
128. Gilbert, Denis Peter. 1980. Deterministic model of soil
moisture to predict forage yield on semiarid rangelands.
Tucson, AZ: University of Arizona. 97 p. M.S. thesis.
129. Giner-Mendoza, Mateo. 1986. Effect of clipping on
photosynthesis, respiration and production of Eragrostis
lehmanniana Nees and Digitaria Californica (Benth.) Henr.
Tucson, AZ: University of Arizona. 54 p. M.S. thesis.
130. Glendening, George E. 1937a. Improving depleted ranges
through artificial revegetation. Western Livestock Journal.
November: 3.
131. Glendening, George E. 1937b. Litter aids germination of
grass seeds and establishment of seedlings. Research Note 7.
Tucson, AZ: U.S. Department of Agriculture, Forest Service,
Southwestern Forest and Range Experiment Station. 2 p.
132. Glendening, George E. 1937c. A method of revegetating
small key plots on eroded areas. Research Note 8. Tucson,
AZ: U.S. Department of Agriculture, Forest Service,
Southwestern Forest and Range Experiment Station. 2 p.
133. Glendening, George E. 1937d. Reseeding on denuded "adobe
flats." Research Note 19. Tucson, AZ: U.S. Department of
Agriculture, Forest Service, Southwestern Forest and Range
Experiment Station. 2 p.
134. Glendening, George E. 1938. The place of tanglehead in
artificial revegetation. Research Note 37. Tucson, AZ: U.S.
Department of Agriculture, Forest Service, Southwestern Forest
and Range Experiment Station. 2 p.
135. Glendening, George E. 1939a. Comparison of the effects of
various kinds of artificial litter upon the germination of
grass seeds. Research Note 61. Tucson, AZ: U.S.
Department of Agriculture, Forest Service, Southwestern
Forest and Range Experiment Station. 4 p.
136. Glendening, George E. 1939b. The development of
tanglehead (Heteropogon contortus) grass seedlings as
related to soil moisture and competition. Tucson, AZ:
University of Arizona. 33 p. M.S. thesis.