Digital Commons Network^™

Precision Drought Stress In Orchards: Rootstock Evaluation, Trunk Hydration And Canopy Temperature, Lance V. Stott

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Tree fruit crops are of high value, but use a lot of water. Precision irrigation has the potential to save water while simultaneously improving crop quality. The timing and method of precision water stress in various tree fruit crops has been widely studied. However, in order to successfully employ precision irrigation methods in orchards, an accurate measurement of tree water status is required. Currently, stem water potential is the preferred indicator. However, this measurement is tedious and cannot be automated. Because measurements must be taken near solar noon (approximately 1:30 PM MDT in the summer in northern Utah), the number …

Postharvest Degradation Of Microalgae: Effect Of Temperature And Water Activity, Jacob A. Nelson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Though usually a nuisance in swimming pools and ponds, algae has the potential to be a valuable commodity for use as food and fuel. But before algae butter and biofuel become commonplace, issues with harvesting and storing this new crop need to be overcome. Though there has been ample research into how to grow and use algae, scientists have spent little time figuring out what to do after you pull it out of the water and before you eat it (or turn it into biodiesel). Algae, like all food products, starts to spoil as soon as it is harvested.

This …

Optimizing The Physical And Nutritional Environment Of Unleached Root-Zones, Curtis B. Adams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Unleached root-zones represent an environmental ideal by eliminating wasteful leaching of nutrients and water. NASA grows plants in space in unleached root-zones, incorporating polymer-coated fertilizer (PCF) into a ceramic media (Turface or Profile). However, lack of growth productivity in space has led to the need for research to improve the nutritional and physical environment of the root-zone, which is the objective of this research. PCF types are diverse in release characteristics and the effects of temperature and substrate water content have not been well characterized. In spite of widespread use, studies on chemical properties and applied studies to verify soil …

Effect Of Blue Light And Temperature On Leaf Expansion, Stem Elongation, And Growth, Tracy A. O. Dougher

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Short height and high yield per unit energy in controlled environments are essential to the success of a food production system for spaceflight. Temperature and light quality can be manipulated in controlled environments to reduce plant height and increase yield. Although the effects of temperature on height and yield are well studied at ambient CO₂, temperature effects at elevated CO₂ with a hydroponic root zone are not well characterized. We studied soybean yield and height under two lamp types over a broad range of temperatures. Temperature had little effect on yield or height, but lamp type had …

The Influence Of Certain Growth Hormones On Plant Growth At Cold Temperatures, Michael D. Salvesen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Studies were conducted to determine the effect of externally applied growth hormones on winter rye (Secale cereale var. cougar). The rye was grown under the snow in a specially prepared tunnel on a mountain side near Logan, Utah. These plants showed a remarkable ability to grow at 0°C. Three growth hormones, kinetin, gibberellic acid (GA), and auxin (indole-3-acetic acid) were externally applied to rye seedlings growing in the tunnel. These seedlings were alter weighed, measured and tested for soluble protein content. The three hormone treatments had no significant effects on the fresh weights or shoot lengths of the …

The Effect Of Environment And Cultural Practices On The Cold Hardiness Of Peach Wood, Larry A. Sagers

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Studies were conducted to better understand the effect of temperature, photoperiod, cultural practices, and growth regulators on the hardening and dehardening of peach tree wood.

Greenhouses were constructed to control temperatures to which peach trees were exposed. It was noted that hardening and dehardening usually followed the temperature fluctuation fairly closely. However, trees exposed to temperatures above 60 F (15.6 C) became hardy to 0 F (-17.8 C).

A photoperiodic response in regard to an increase or decrease in hardiness was not definitely observed in peach wood. Extended photoperiod did not produce any significant effect on hardiness. Defoliation, bloom date, …

Temperature Effect On Leaf Water Potential Measurements, Rex J. Prosser

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Silver foil psychrometers were used to monitor water potential in different portions of maize leaves which were subjected to temperature gradients. The psychrometers were preliminarily calibrated over standard NaCI solutions at temperatures ranging from 5°C to 45°C in an aluminum plate apparatus designed to provide uniform temperatures within each psychrometer even while overall temperature was changing. Based on the calibrations, empirical temperature correction equations were derived and used to correct psychrometer readings at different temperatures to equivalent values at 25°C. Temperatures on a single maize leaf were varied by placing the long leaf through an insulated box with several compartments …

The Effect Of High Air Temperature And Depth Of Planting On The Emergence And Development Of Selected Grain Sorghum (Sorghum Vulgare) Cultivars, Jhander Orihuela

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The behavior of seedlings of six sorghum cultivars planted at 2.5, 5.0, 7.5, and 10.0 centimeters was studied in growth chambers at air temperatures of 28, 32, 36, and 40 centigrades (daytime).

A day length of 12 hours and a nighttime air temperature 8 centigrades lower than daytime were used throughout.

The cultivars, three hybrids and three varieties, were grown in sand culture. Field moisture capacity was maintained during the period of observation.

After 14 days of growth, data were collected on the emergence percentages, above ground growth, above ground oven dry weights, below ground growth, and below ground oven …

The Effect Of Changing Temperatures On Hardiness, Respiration, And Intensity Of Rest Of Dormant Peach And Apricot Buds, Anthony H. Hatch

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

studies were conducted to better understand the influence of temperature on the rest period of dormant peach and apricot buds. Gleason Elberta peach and Chinese apricot trees in the field at Howell Experiment Station in Ogden were used to evaluate rest intensity, respiration, and cold hardiness in relation to temperature.

A rest intensity curve was obtained for both species using various concentrations of gibberellic acid. It was found that temperature had no direct effect on the depth of rest and that the depth of rest had no measurable influence on respiration and cold hardiness.

Respiration of flower and leaf buds …

Temperature And Atmospheric Humidity As Factors Influencing Seed Setting In Alfalfa, Lealand A. Clark

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

For many years seed growers have thought that definite relationships existed between seed production and the weather. When this subject is approached there is little unity of opinion, even among neighboring seed growers. This lack of unity would indicate that growers generally are aware of some cause which affects seed setting, but they are not certain that any particular condition of the weather is the chief contributing factor. Scientific writers¹ on the subject are also confident that weather is probably one of the major factors influencing seed production.