No description available.

Urea and triple superphosphate (TSP) are important N and P fertilizers, respectively, but they suffer from inefficiency because of NH$ sb3$ volatilization and phytotoxicity and P fixation. Combinations of urea and TSP or KCl might improve N and P use efficiency primarily through pH changes. Mixtures of urea, TSP and KCl, either compacted or blended, were studied as to NH$ sb3$ volatilization, denitrification and P transformation in soils, and N and P use efficiency in crops. Soils studied included a Ste. Rosalie clay (Humic Gleysol), an Ormstown silty clay loam (Humic Gleysol), a Chicot sandy clay loam (Grey Browm Luvisol), a St. Bernard loam (Melanic Brunisol) and an Upland loamy sand (Humo Ferric Podzol). Triple superphosphate or KCl reduced urease activity and delayed urea hydrolysis primarily through acidification. Ammonia volatilization decreased when urea was surface-applied with TSP or KCl. The depressive effect of TSP on NH$ sb3$ volatilization was reduced and the KCl effect was increased in the soil with high exchangeable acidity. Phytotoxicity from banded urea, NO$ sb2 sp-$ accumulation and denitrification declined with added TSP. Urea hydrolysis caused a rise in pH and dissolution of organic matter in soils, and as a result, Mehlich (3) and water extractable P increased when urea were banded with TSP. Corn yield and N and P use efficiency were improved with application of mixtures of TSP and urea as compared with urea or TSP alone. Compacted mixtures of urea and TSP or KCl were superior to blended mixtures, possible because of the intimate association of fertilizer dissolution products. Compacted mixtures of urea and TSP or KCl hold promise for improved agricultural productions.

No description available.

No description available.

Graduation date: 1933

Thesis (Ph. D.)--University of Hawaii at Manoa, 1995. / Includes bibliographical references. / Microfiche. / xiv, 153 leaves, bound ill., map 29 cm

Typescript. / Bibliography: leaves [180]-190. / xviii, 218 l illus

Bibliography: leaves 207-222 / xvi, 222 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Soil Science, 1987

Thesis (Msc Food Sc (Food Science))--University of Stellenbosch, 2006. / Consumers demand beef products of consistent and satisfactory tenderness, acceptable meat colour, the necessary nutritional value, as well as being microbiologically safe. However, inconsistency in meat quality, and particularly tenderness, is a problem that has continuously plagued the meat industry Firstly, an investigation was undertaken to determine the muscle variation, particularly in the tenderness of South African beef muscles. Beef muscles were removed from the right-side of beef carcasses and the physical, chemical and sensory characteristics determined 72 h post-mortem. As the beef muscles differed significantly (P≤0.05) in these attributes, the need for increased attention to enhanced processing and meat ageing is accentuated. Therefore, two further investigations were executed, including an enhancement study and a shelf-life study. The enhancement study determined the time effect of a blend of sodium and potassium salts, various phosphates and lactates on the physical quality, chemical composition and sensory quality of South African beef muscles. The corresponding muscles were removed from the left-side of the same beef carcasses and infused 3 d postmortem. The changes in beef quality over 19 d and the initial proximate and mineral composition were determined. The infused beef increased in tenderness, while maintaining an acceptable red colour. The infused muscles had higher moisture and ash contents, and lower lipid and protein contents. The mineral content of the treated muscles increased due to the minerals contained in the infusion blend. For the sensory analysis, beef muscles were stored under vacuum for 24 h (4°C) until the physical data had been collected. Thereafter, the muscles were stored at −18°C until the descriptive sensory analysis could be performed. The infusion of beef muscles successfully enhanced the sensory attributes, resulting in significantly (P≤0.05) more juicy and tender beef. When used in a consumer preference test, the infused samples illustrated a significantly (P≤0.05) higher degree of liking. In the shelf-life study the effect of the blend on the physical attributes, proximate composition and microbial growth of South African beef muscle was determined. One muscle from the left-side of beef carcasses was infused 4 d post-mortem. The purge loss, colour changes and the microbial growth on the muscle steaks over 10 d (overwrap storage) was determined. The infused muscle showed greater colour loss (lower a*, b* and chroma values) during the 10-d period. Physical analysis (purge loss) indicated a significant difference (P≤0.05), with the treated sample losing 2.78% more purge. The infusion extended the microbiological shelf-life of beef by 1 d. Improvement of beef quality and its consistency is essential for the survival of the beef industry. The infusion of beef muscles has the potential to improve the current status of low meat consumption and inconsistent tenderness of fresh beef in South Africa. Despite decreased colour stability in the infused steaks, negatively affecting the purchasing decision of the consumer, the blend could still be applied successfully in the South African meat industry to extend the shelf-life of fresh beef and improve meat quality attributes, providing the consumer with a more acceptable beef product.

Thermal desorption (TD), a remediation method used to remove hydrocarbons from contaminated soils, may cause changes in soil properties that threaten soil function and plant productivity. The goal of this research is to better understand the effect that TD treatment has on soils intended for agricultural use. A series of soil phosphorus (P) sorption and desorption experiments were conducted on soils before and after TD treatment to determine P availability for plant uptake and risk for run-off. TD-treated soils retained more P, likely due to mineral transformations of Fe- and Al-oxides. In addition, a three-year field study using mixtures of topsoil (A), crude-contaminated soil (SP), and TD-treated soils (TDU) was conducted. Yields were significantly greater in plots that included A in the mixture compared to SP and TDU soils alone. TD-treated soils can be a replacement for topsoil, but the addition of topsoil will reduce the time to successful reclamation.