1950-1979

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Open Access
Hell hath no limits
(Colorado State University. Libraries, 1970) Taylor, Hallie Deering, author; McMurray, George R., advisor
The first part of the thesis is a study of the mythological elements in the works of José Donoso. Seen on the mythological plane, the novels are not so much a trilogy as variations upon a single theme. Coronación presents the basic sketch of the powerful goddess figure, which is studied from two distinct angles in the later novels. Esta domingo is concerned with the Great Goddess of the earliest myths, before the patriarchal figure came into power. El lugar sin límites deals with the later conflict of the goddess and the god, and in this variation the goddess is overpowered. The second part of the thesis is the translation into English of El lugar sin límites. The novel has two themes: the portrayal of the power of a corrupt politician, who destroys a small town and dooms its inhabitants to oblivion or death; and the life and brutal murder of an aging transvestite, who is one of the town's inhabitants.
Open Access
The welfare effects of a market allocation of an exhaustible resource
(Colorado State University. Libraries, 1977) Ward, Frank A., author; McKean, John R., advisor
In recent years, cost-benefit theorists have developed “net benefit" measures of welfare change attributable to shifts in the allocation of flow resources. Presumably, such welfare-change measures have been developed as an attempt to minimize the wastage of resources on unsound projects. However, to the author's knowledge, no such welfare-change measure has been developed to rank alternative allocations of an exhaustible resource. This dissertation attempts to devise such a measure. The measure is developed in three steps. The first step (Chapter two) is an explanation of how a free market allocates the exhaustible resource over time. Inquiry is made as to how the time path of extraction is affected by changes in (1) production costs, (2) total known supply, (3) the costs of a substitute techno1ogy, and (4) the discount rate. Knowledge of the allocation explored in this step is important, because, once determined, the market outcome can be compared to some appropriately-defined efficiency norm. The second step (Chapter three) develops an efficiency norm as a basis for determining whether the market depletes the exhaustible resource too quickly, too slowly, or at the right rate. The third step (Chapter four) of this dissertation is an attempt to develop a measure which quantifies how well the market's time-use of the mineral approaches an efficient allocation. The methodology used is the development of a measure of welfare change. Specifically, this measure is designed to ascertain the net change in benefits attributable to changes in either of two generalized distortions relevant to the market for an exhaustible resource. At all three steps, this dissertation draws from and extends the theory of exhaustible resources. The first step is an extension and refinement of the comparative statics of competitive mining theory. At the second step, the optimality properties of a market allocation over time are examined. At the third step, the degree to which the market breaks down is the subject of concern. Specifically, an extension of currently-accepted welfare-loss theory is developed and made applicable to the exhaustible resources sector. The results of this dissertation are that, indeed, such a welfare-loss measure can be quantified. By incorporating (1) the effect of a change in a market distortion on the private profit-maximizing output path of each of n mining firms, and (2) the effect of these n output path changes on aggregate total discounted net benefits, a welfare-loss measure is developed. The measure can, in principle, rank alternative allocations of an exhaustible resource on the basis of the net size of two generalized distortions, the values of which would depend on the size of the policy variable under consideration.
Open Access
The impact of living environments on engineering students
(Colorado State University. Libraries, 1976-04) McKelfresh, David Alan, author; Hotchkiss, C. W., advisor; Neidt, C. O., committee member; Kuder, James M., committee member
The purpose of this study was to compare and contrast three groups of engineering students at Colorado State University on academic achievement, and specific items of satisfaction and awareness to determine if measurable differences do exist. The three groups consisted of those engineering students living in the engineering residential academic unit, in other residence halls, and off campus. The sample for this study consisted of 397 engineering students. The engineering questionnaire was administered to the sample while 1975 grade point averages were obtained. The hypotheses under consideration were tested by use of the F test. Findings indicated that there were statistically significant differences for the two groups of freshmen and the three groups of non-freshmen on certain items of satisfaction and awareness. It was concluded from the data that residential academic units have a positive impact on students.
Open Access
Cavitation damage scale effects: sudden enlargements
(Colorado State University. Libraries, 1975) Stripling, Travis Earl, author; Tullis, J. Paul, advisor; Olson, H. G., committee member; Meroney, Robert N., committee member; Ball, James W., committee member
The present study was aimed at investigating the cavitation damage downstream from sudden enlargement energy dissipators. Tests were conducted on geometrically similar circular orifices of five different orifice to pipe diameter ratios in three different pipe sizes of: 3-, 6-, and 12-inches. Highly polished 1100-0 aluminum specimens were mounted in the downstream pipe wall to detect the cavitation damage. Two different stages or levels of cavitation damage were defined for study: (1) "incipient damage" level based upon maintaining a maximum pitting rate of 1 pit/in.2/min. on 1100-0 aluminum, (2) cavitation damage regime where the maximum pitting rate was greater than 1 pit/in.2/min. Previously defined incipient damage scaling equations based upon damage data taken in the 3-in. pipe accurately predicted the incipient damage condition in the 6- and 12-in. pipes. Pressure scale effects on the incipient damage condition were constant for all pipe sizes tested. There were no size scale effects found for the incipient damage condition based upon maintaining a maximum pitting rate of 1 pit/in.2/min. The incipient damage condition was investigated in greater detail by studying the variation in the volume of the damage pits in the soft aluminum. The volume of the damage pit was related to the energy expended in format ion of the pit which was assumed to be a measure of the intensity of the cavitation impact blow forming the pit. It was found that at the incipient damage condition the intensity of cavitation impact blows varied with pipe size and orifice to pipe diameter ratio. The damage in the cavitation damage regime was found to be a function of both cavitation pitting rate and intensity of cavitation impact blows (energy of pit formation). A cavitation intensity parameter, defined as the product of cavitation pitting rate and energy of pit formation, was used to measure cavitation damage. Data was presented to show the general variation of cavitation intensity under conditions of varying cavitation index, varying upstream pressure, and varying pipe size. In addition, the cavitation damage scaling evaluations introduced by Thiruvengadam were used along with experimentally measured flow field data to predict variations in cavitation pitting rate and intensity of impact blows. The experimental results indicate that it is impossible to simulate total prototype cavitation loading conditions in terms of both cavitation pitting rate and intensity of impact blows in a hydraulic model of reduced size. An example is introduced demonstrating this fact. An alternative method using the cavitation intensity parameter is proposed for modeling prototype cavitation loading conditions in a model of reduced size.
Open Access
Function of the cecal microflora in sage grouse nutrition
(Colorado State University. Libraries, 1968) Barber, Thomas Amos, author; Nagy, Julius G., advisor; Nagy, Julius G., advisor; Mayeux, Jerry V., committee member; Ryder, Ronald, committee member; Mayeux, Jerry V., committee member; Ryder, Ronald, committee member
An investigation of the cecal bacteria of sage grouse (Centrocercus urophasianus) was undertaken in an effort to obtain information on the function of the cecal microflora in the nutrition of this species. The project included experiments in three main areas: (1) isolation and characterization of cecal bacteria; (2) gas chromatographic analysis of cecal contents for VFA produced by bacterial fermentation; (3) chemical analysis of sage grouse feed and droppings. Cultures of bacteria from the cecal contents of sage grouse showed a large bacterial population to be p re sent. Predominant organisms in cecal contents were similar to normal avian enteric types. Organisms resembling Actinomyces bifidus and a streptococcus-like form were the most numerous types in the ceca. Solid media including the supernate of centrifuged cecal contents ( CFAM) and clarified rumen fluid (RFAM) proved to be superior to all other media tested for total counts of cecal bacteria; the use of these media was a necessity for the culture of the two predominant types of cecal organisms. Total culture counts of cecal bacteria in winter-killed birds showed a mean of 18 X 109 organisms per gram of wet cecal contents as compared to 30 X 109 for those collected in summer. Only insignificant numbers of cellulose-digesting organisms were cultured despite use of several enrichment media. Large amounts of volatile fatty acids (VFA) were produced by the cecal microbial fermentations. Higher levels of VFA were present in ceca in winter when the birds were on total sagebrush leaf diets and lower total numbers of cecal bacteria were present. Analysis of cecal contents showed that they contained only about 3% fiber (of a 10-16% dry weight). The high concentration of fiber in rectal droppings accounts for nearly the total amount ingested in sagebrush leaves. Essential oils of sagebrush are present in greater amounts in the Type A-3 sagebrush leaves selected by the grouse examined as summer food. Crops of winter-killed birds contain a mixture of all three subtypes of sagebrush; total oil levels in the digestive tract at this season were higher than in the summer when forbs comprised a portion of the diet.
Open Access
Observation of progressive convective interactions from the Rocky Mountain slopes to the Plains
(Colorado State University. Libraries, 1979) Philipp, Ceri Burns, author; Vonder Haar, Thomas H., advisor; Cotton, William R., committee member; Meiman, James R., committee member
Geosynchronous satellite data were employed for a climatological study of two summers' data and for a specific case study to observe convective interactions between the eastern slopes of the Colorado Rocky Mountains and the plains of eastern Colorado and western Kansas. The climatological study involved imagery for May-August 1976 and 1977 for a study region defined from eastern Utah to western Kansas that was divided into five areas. Development and movement of convective activity from the mountains to the plains was identified by the satellite imagery analysis for 12% of the 1976 summer days (13 out of 108) and 17% of the 1977 summer days (16 out of 94). When precipitation records for stations in western Kansas were consulted, it was found that these satellite- identified development and movement days made a significant contribution to the monthly and seasonal total precipitation for this area. There were instances when the contribution was greater than 90% (for some months) and greater than 50% (for seasonal total). Further results from the climatological study showed that cumulus clouds were most likely to form in the southwestern and central Colorado mountains between 0700 and 1000 MDT (1300 to 1600 GMT). Mountain regions were generally clearing remnants of old cells during the late afternoon, evening and night hours with development and growth of new cells occurring in the early morning to early afternoon. Plains regions generally were clearing remnants during morning and early afternoon hours with convection developing in late afternoon, evening and night hours. A quantitative case study was performed for 4 August 1977 when 3-minute rapid scan satellite data were available. It was a day when optimum conditions for development and movement from the mountains to the plains existed. Computer programs on the All Digital Video Imaging System for Atmospheric Research (ADVISAR) were used to study changes in cloud size, cloud number, and cloud brightness for two areas in Colorado. The first area was in the northeastern Colorado Rocky Mountains where the primary storm system moved through. The second area was in southern Colorado (near Pueblo) which included both mountains and plains regions and primarily stationary convective activity. From the quantitative study, no definite correlation was found between changes in cloud number and changes in cloud brightness. Differences in both quantities over 3-minute intervals were found to be significant and were sometimes larger than 6 or 9-minute changes. Both areas showed varying patterns of increasing and decreasing cloud number and brightness. The first area with the active moving system tended to have greater mean brightness and more time periods with large clouds than the stationary system area. It also had larger "largest clouds" over the time period studied (1100 - 1624 MDT) than the second area.
Open Access
A theoretical investigation of convective patterns in the lee of the Colorado Rockies
(Colorado State University. Libraries, 1970-03) Dirks, Richard A., author; Reiter, Elmar R., advisor; Grant, Lewis, committee member; Gray, William, committee member; Morel-Seytoux, Hubert, committee member
The western Great Plains are observed to be the formation region for many of the summer convective systems in the central United States. Convective activity is greatly reduced in the immediate lee of the Colorado and New Mexico Rockies while it is intensified about a hundred kilometers eastward. An explanation of these observed convective patterns is proposed on the basis of a regional scale Rocky Mountains-Great Plains circulation system. A two-dimensional numerical model of a large scale mountain-plain circulation is presented which includes the effect of a slightly sloping plain. The equations are integrated over periods of two to eight hours for various initial conditions of thermal stability and ambient wind. An increase in thermal stability is found to suppress the developing circulation while the circulation is enhanced by an ambient shearing wind. Typical observed stability and ambient wind fields yield an interacting two cell circulation with a strong cell over the mountain slope and a weaker cell over the plain. The resulting airflow is characterized by strong descent (m sec -1) in the immediate lee of the mountains and weak ascent (cm sec -1) in a broad region 100 to 300 km leeward. An investigation of contributing factors reveals the effect of the plain slope to be a primary cause of the ascending flow over the plain. The flow patterns which develop correspond well with observed diurnal oscillations in upper wind profiles over the plains with regard to velocity magnitude, time of reversal, and depth of flow. The dynamic effects of the circulation are found to be of sufficient magnitude to control convective activity. The spatial distribution of the dynamic effects is also in general agreement with observations of related convective activity. Nocturnal cooling reverses the circulation around "sunset" and results in ascending flow in the near lee of the mountains. This compares favorably with observed convective activity in that region. An examination of orographic waves and other plausible mechanisms finds that these are not generally applicable over the wide range of observed conditions. This restriction does not apply to the Rocky Mountains-Great Plains circulation system.
Open Access
Absorption of atmospheric ozone in the .3 micron region at Fort Collins
(Colorado State University. Libraries, 1964-02) Wilsey, Neal David, author
Open Access
Atmospheric water balance of the Upper Colorado River Basin
(Colorado State University. Libraries, 1968-01) Rasmussen, James L., author; Riehl, Herbert, advisor; Marlatt, William E., committee member; Dils, Robert E., committee member
The atmospheric branch of the hydrologic cycle is investigated to determine the wintertime accumulation of water over the Upper Colorado River Basin. The parameter precipitation minus evaporation is computed as a residual from the atmospheric water balance equation. The study covers the seven winter seasons 1957 through 1963. The results show that the periods of evaporation as well as the periods of heavy precipitation determine the seasonal water balance of the basin. The seasonal course of daily evaporation rate is determined. The evaporation rate varies by a factor of two over the winter season. Further, a strong decay with time of evaporation rate is observed during the early and mid-winter months. A less pronounced decay is obtained during March and April. The basin precipitation data obtained from the atmospheric water balance computation are compared to a basin precipitation estimate independently obtained using data from fourteen rain gauges. The conclusion is reached that the gauge data underestimate the basin precipitation by about fifty per cent. Much of this bias is shown to be due to the lack of sampling over the high elevation regions where the precipitation is greatest. The wintertime accumulation of water over the basin is shown to be highly related to the April through March runoff from the basin. The relationship shows that the accumulated water is apportioned by a ratio of one to four between runoff and evaporation respectively. Finally the application of the atmospheric water balance computation to the problem of runoff forecasting is discussed.
Open Access
Polyembryony in Lycopersicon esculentum
(Colorado State University. Libraries, 1963-01) Inayatullah, Hafiz, author; Foskett, Richard L., advisor; Pettus, David, committee member; Wood, Donald R., committee member
A study of polyembryonic tomatoes was conducted with two major objectives. The first was to determine means of obtaining a higher frequency of polyembryonic seeds. The second was to study various growth traits of twin plants, especially to observe differences between twins which might be attributable to a nutritional competition within polyembryonic seeds. The variety Beefsteak, a seed lot of which was previously observed to produce a high incidence of twins, was found in this study to transmit this trait to its progeny. F1 weed of reciprocal crosses with low incidence lines showed that inheritance of a high incidence of twinning was neither dominant nor maternal since in no case was there a high incidence of twinning in any of the progenies. Self-pollinated seed taken from F1 plants of these crosses indicated a more complex inheritance than would be afforded by a single gene. Reciprocal crosses between the Beefsteak line and Premier both produced a higher incidence than crosses between the same high twinning line and Red Jacket. It was found that detection of polyembryonic seeds was better accomplished where seeds had been separated by weight. Heavy seeds were found to contain a higher proportion of twins. Detection of polyembryonic seeds was further improved by soaking heavy seeds in Chlorox, a 5.25 percent solution of sodium hypochlorite, for five minutes. Chlorox clarifies the seed coat tissue and enables the observer to see the outline of the embryo more clearly in single embryo seeds than in polyembryonic seeds. Chlorox treated, heavy seeds in which the embryo could not be clearly discerned through the seed coat produced twins at a rate of 1 in 17 seeds; whereas, non-treated and randomly selected seeds of the same seed lot produced twins at the rate of 1 in 125 seeds. A distinction was made between the each twin pair according to which seedling completely emerged first from the seed coat. It was found that the twin that first completely emerged was later in flowering and slower in growth. Differences between the twins were not significant for height to inflorescence, number of flowers in first and second inflorescences, or number of nodes below first inflorescence.
Open Access
The relationship of the dwarf gene (d₁) to seed germination and seedling growth in Lycopersicon esculentum Mill
(Colorado State University. Libraries, 1964-06) Hanzely, Laszlo, author; Foskett, Richard L., advisor; Danielson, Robert E., committee member; Curtis, Byrd C., committee member; David, D. W., committee member
A study of identification of the dwarf phenotype in seedling stage, of various factors affecting seed germination and seedling emergence and of growth responses to various moisture conditions in seedling stage of the dwarf phenotype was made. Characters, such as hypocotyl length, cotyledon length and cotyledon index (length/width) were found to be easy and precise methods of distinguishing dwarf and normal seedlings. The germination rate and time of dwarf seed when compared with normal seeds was found to be similar in petri dishes under moisture tensions of zero, three and six atmospheres and at various temperature levels. Slower emergence from soil and sand was observed for dwarf seedlings, regardless of temperature, planting depth or light conditions. Percent emergence of dwarf seedlings was lower than that of normal seedlings, particularly following planting at low temperature. Dwarf and normal seedlings were similar for fresh plant weight to weight and root weight at high moisture tensions induced by mannitol and control conditions. Root-top ratios were found to be higher for dwarf seedlings than for normal seedlings when grown under both high and low moisture tensions. A slower development of wilting symptoms at various number of days following suspension of watering, a higher percent of recovery following rewatering and a smaller percent of foliage damage resulting in chlorophyll destruction was shown to occur for the dwarf seedlings at moisture tensions achieved through the gradual water loss by soil.
Open Access
Phenotypic effects of jointless gene in tomato
(Colorado State University. Libraries, 1962-03) El Sayed, Mohamed H. K., author; Foskett, Richard L., advisor; Chapman, Harold W., committee member; Parke, Robert V., committee member
A study of the pleiotropic effects of the jointless gene in tomato (j1) was conducted in both the greenhouse and the field. This gene was found to mask the determinate character, controlled by a single recessive gene (sp.). This effect was found by crossing the phenotypically indeterminate and jointless variety Dwarf Champion with known indeterminate and determinate jointed varieties. The F1 of the cross with an indeterminate variety was indeterminate, but there were determinate segregates in the F2 progeny. Furthermore, the F1 of the cross with a known determinate and no indeterminate-jointed plants were observed in the F2 generation. All jointless plants in this study were phenotypically indeterminate. There were fewer flowers per inflorescence on jointless plants than on jointed plants in all progenies and treatments in the study. It was also noted that the modul number of all jointless populations was three. This number remained constant in F2 populations regardless of jointed parent. It was also not increased by removing leaves after the fourth node, a treatment which increased the number of flowers in jointed inflorescences. Although the jointless character decreased number of flowers per inflorescence, the percentage of flowers setting fruits was higher among jointless plants than among jointed. This resulted in almost as many fruits per inflorescence among jointless plants as among jointed. Number of days until the opening of first flower and number of nodes before the first inflorescence were in all cases greater among jointless plants than among jointed. Eight inflorescences were observed from each plant in the field study. In this study all jointless plants had some leafy inflorescences and all the observed inflorescences were leafy in 33 percent of the jointless plants. On the other hand, 70 percent of the jointed plants had no leafy inflorescences and no jointed plants were found with more than four of the eight inflorescences leafy.
Open Access
A correspondence course on house plants
(Colorado State University. Libraries, 1963) Gundell, Herbert Carl, author; Binkley, A. M., advisor
Open Access
The influence of herbicides on microbial activity in the soil
(Colorado State University. Libraries, 1956-07) Bakes, Donald B., author; Johnson, Donald, advisor; Morrison, S. M., committee member; Crone, E. B., committee member
Open Access
Causes of post harvest discoloration of potato chips from summer potatoes
(Colorado State University. Libraries, 1960-05) Clegg, Max DeWayne, author; Chapman, Harold W., advisor; Johnson, Gestur, committee member; Fults, Jess L., committee member
Early summer potatoes are harvested from the Gilcrest and Rockyford areas in Colorado. Potato chip processors use these newly harvested potatoes and have found them to be erratic in performance, some lots producing light colored chips, others making a dark undesirable product. Information is lacking on the causes of this after harvest darkening. Three plots (a highly fertility, a low fertility and a low fertility plus 120 lbs. of nitrogen) were planted using the variety Irish Cobbler. These plots were located in the Gilcrest early potato producing area. Potatoes were harvested July 7, 11, 18, 25, August 1 and 8, and placed into 50°, 70°, and 90°F storage. An injury treatment was added to the July 25 harvest. At three day intervals over a period of 21 days, respiration, chip color and some chemical analyses were determined. Results show that immature potatoes can not be held in storage for chipping purposes. Delaying the date of harvest will improve the storage capability. Storage at 50°F is detrimental to summer chipping potatoes. Storage at 70°F or above is recommended. The trend of treatment was that potatoes from Treatment II (low fertility, no nitrogen) produce the lightest colored chips. Injury to tubers increases sugar accumulation and results in darker chips. The high non-reducing sugar content of early potatoes may be the main cause of after harvest darkening of potato chips. This high sugar content may be a readily available source of sugar, easily converted into reducing sugars, which in turn causes the potatoes to darken when chipped.
Open Access
Bedding plant nutrition
(Colorado State University. Libraries, 1979) Schrock, Patricia A. Tew, author; Goldsberry, Kenneth L., advisor
Three nutrition experiments were conducted to determine the nitrogen, phosphorus, and potassium nutrient levels necessary to obtain quality bedding plant growth. A soil medium of equal parts (by volume) Fort Collins Clay Loam, Canadian peat moss, and perlite, and soilless medium of equal parts (by volume) Canadian peat moss and vermiculite were used in all experiments. Pelargonium hortorum 'Sprinter Scarlet' and Petunia hybrida 'Candy Apple' seedlings were grown in the 2 media and watered with 5 nutrient solutions containing varying ratios of NO3-:NH4+, each resulting in a total NO3- plus NH4+ concentration of 15 meq 1-1. There were no significant differences in height, fresh and dry weights, or number of vegetative breaks in soil-grown plants due to the N sources. Plant growth in the soilless medium was substantially reduced as the proportion of NH4+ increased above 50%. Plant quality of Pelargonium hortorum 'Sprinter Scarlet' and Petunia hybrida 'Candy Apple' were also evaluated in the 2 media when watered with 12 nutrient solutions containing 4 nitrogen concentrations (half NO3-, half NH4+) of 7.0, 11.5, 14.0, and 17.5 meq 1-1, and 3 potassium concentrations of 2, 4, and 6 meq 1-1. Potassium concentrations above 2 meq 1-1 had little or no affect on plant growth in either media. Increasing nitrogen rates caused increased plant height, and fresh and dry weights. The 7.0 meq 1-1 nitrogen-grown plants showed signs of nitrogen deficiency. Maturity, in terms of flowering and number of vegetative breaks, was not affected by the nutrient regime. Optimum plant growth in both media was produced with 11.5 meq 1-1 nitrogen and 2 meq 1-1 potassium treatment. Seedlings of Pelargonium hortorum 'Sprinter Scarlet', Petunia hybrida ' Pink Magic ', Impatiens holstii 'Elfin Red', and Tagetes patula 'Goldie' were grown in the 2 media with 4 phosphorus treatments consisting of 0 kg m-3 treble superphosphate preplant plus a continuous feed using 25-0-25 (1.408 meq 1-1 H2PO4-, 200 ppm P2O5), and 0, 3, and 6 kg m-3 treble superphosphate preplant plus a continuous feed of 20-20-20 (1.408 meq 1-1 H2PO4-, 200 ppm P2O5). All species, except impatiens, showed increased growth with increased phosphorus levels; impatiens gave little or no response to phosphorus treatments. Flowering time of all species was unaffected by the treatments. The 3 kg m-3 treble superphosphate plus a continuous feed of 20-20-20 (1.408 meq 1-1 H2PO4-, 200 ppm P2O5) gave the best plant response in both media.
Open Access
Application of the PERT scheduling technique to a nursery operation
(Colorado State University. Libraries, 1979) Ludwick, Beverly A., author
Improved management techniques are needed by the nursery industry as methods of control and scheduling have failed to keep pace with rapid growth. PERT (Program Evaluation and Review Technique) is a management system which could have useful application to the nursery industry. The PERT system was developed by the United States Navy to coordinate the Polaris submarine program, and is based on a critical path network which allows the user to see important interrelationships. Analysis of these interrelationships allows for the improved coordination, control, and scheduling of a project. The purpose of this study is to investigate the feasibility of applying PERT to nursery production and using the PERT concept in a nursery management classroom. A broad, general network of production activities was developed based on information provided by 13 nurseries. Bailey Nurseries, Inc. of St. Paul, Minnesota, supplied the estimated time durations for each activity in the network. This study deals with three species: Lonicera sp., Cotoneaster sp., and Fraxinus pennsylvanica. Time durations were assigned to each activity necessary in the production of that particular species; each activity was assigned either a date that activity would begin or a date it would be completed. This information was prepared for the computer and reports were generated. The reports which are derived from using the PERT system allow the user to see an overview of the entire operation. Therefore, the effect management's decisions have on interrelated activities can be closely observed and monitored. Though the scope of this study is general, it would appear that the logic and organization necessary in the development of PERT as a nursery management system could greatly benefit the nursery industry and be useful in teaching nursery principles of business and technology.
Open Access
PSIM: a crop scheduling simulation
(Colorado State University. Libraries, 1979) Mattingly, Sue Silver, author; Basham, Charles W., advisor
PSIM is a simulation model of raw product supply for a commercial pea canning operation. The primary purpose of the computer model is generation of planting and harvest schedules based on the heat unit system for predicting crop maturation. The simulation will schedule up to 30 plantings, each consisting of 20 subplantings, for as many as ten cultivars. Output includes a planting schedule, a table of projected harvest dates based on historical temperature data, final harvest dates based on a current year's temperature data, and yield figures. Maturity and yield are treated as stochastic elements in the model and samples are taken from normal distributions for both characteristics. Model rationale is presented along with a program listing, technical and user documentation. The heat unit system itself is examined in a review of the literature.
Open Access
Cold hardiness studies of bermudagrass and Paspalum vaginatum Sw.
(Colorado State University. Libraries, 1979) Ibitayo, Olurominiyi O., author; Butler, Jackie D., advisor; Burke, Michael J., committee member; Dickens, Lester, committee member
The relative cold hardiness of 8 bermudagrass Cynodon sp. and 2 Paspalum vaginatum Sw. cultivars was evaluated in growth chamber by dry weight of regrowth obtained from these turfgrasses. Samples of the turfgrasses which were cold stressed in the field were taken into the greenhouse at regular intervals from fall through winter to spring. The degree of injury of samples subjected to low temperature in the laboratory was estimated via conductivity measurements. The field study related closely to laboratory analyses. There were significant differences between cultivars with respect to cold hardiness. The bermudagrasses appear to be more cold hardy than P. vaginatum cultivars. Of the turfgrasses studied, Brookings appears to be the most cold hardy followed by NEJC, Tifgreen, Pee Dee 102, Tifdwarf, LaJunta, Santa Ana, Tifway, Futurf and Adalayd in decreasing order of cold hardiness. All the cultivars tested were chilling sensitive, but Santa Ana and Tifway were less so than the other grasses tested. The results of the field and chilling injury tests suggest that Brookings is photoperiod sensitive and that it breaks dormancy later than the other cultivars tested.
Open Access
Iron chlorosis in silver maple (Acer saccharum)
(Colorado State University. Libraries, 1978) Morris, Robert L., author; Swanson, Bert T., advisor; Workman, Milton, committee member; Moore, Frank D., III, committee member; Lindsay, Willard L., committee member
Correctives for iron chlorosis have been applied to soil, sprayed on leaves and injected into woody plants. Some success in woody plants has been achieved from soil applied chelated Fe and injected Fe chelates. Silver maple has been unusual in that little response to chelated Fe was found. Experiments were devised to inject silver maples with different Fe chelate formulations, comparing results with a soil applied EDDHA treatment as well as chlorotic and green controls. Silver maple, for the most part, failed to respond to any of the chelate treatments applied. Foliar analyses revealed high levels of foliar Ca in chlorotic leaves compared to green leaves. When the soil producing green and chlorotic plants was analyzed, it was found that total soil Fe levels were higher for green control plants than chlorotic control plants. This increased level of total soil Fe was not reflected in the foliar analysis. There was no major distinction in foliar Fe levels between green and chlorotic tissue. Xylary sap pH and Eh were also recorded for silver maples growing in various solution cultures. Solution cultures were prepared to simulate various types of Fe stress capable of causing Fe chlorosis. Although the solution culture pH varied widely, xylary pH stayed relatively constant. Xylary Eh measurements maintained an even narrower "buffered" range. When pH and Eh were combined on a similar scale (pH+ pe), the xylary sap pe + pH was observed to stay in a narrow range even when solution pe + pH varied widely.