Thesis (MTech (Agriculture))--Cape Peninsula University of Technology, 2018. / Zinc deficiency on various soil types have been reported in arable soils of sub Saharan Africa (SSA) including South Africa. A pot trial was conducted at the Cape Peninsula University of Technology, Wellington campus to investigate the interaction of different application rates of Zn at various soil pH on the grain yield and quality of spring wheat in a completely randomized factorial design replicated three times. The four soil pH tested were: pHA: 5.1, pHB: 5.6, pHC: 6.1, pHD: 6.6 which correspond to lime application at 0, 0.5, 1 and 1.5 t/ha. Five Zn rates (Zn1: 3.5; Zn2: 4.5; Zn3: 5.5 Zn4: 6.5, and Zn5: 7.5 mg /kg soil which correspond to Zn1: 7; Zn2: 9; Zn3: 11; Zn4: 13 and Zn5: 15 kg /ha) were applied at two (planting and flowering) growth stages. Yield and yield component data collected were analyzed using SAS version 9.2 and means were separated by Duncun’s Multiple Range Test (DMRT). The results showed that grain yield and yield components were significantly affected by lime application pHC (6.1): 1t/ha at planting. Zn application at planting had no significant effect on the grain yield and yield components. However, at flowering, the simultaneous increase of Zn along with increase in lime positively affected grain yield and yield components. Plant analysis showed that at both stages (planting and flowering), Zn application, especially at pH 6.6, significantly increased P, K, Ca, Na, Mg Fe, Cu and B concentrations in wheat grain, but the concentrations of N, Mn, Zn and protein remained unaffected. Zn application had no effect on most nutrients due to the presence of lime. While the absence of lime, Zn4: 6.5mg/kg (corresponding to 13kg/ha) significantly increased the nutrients. In addition, Zn3: 5.5mg/kg (corresponding to 11kg/ha) promoted Zn absorption by grain in all treatments.

Bibliography: leaves 290-324. This thesis investigates two avenues suggested by Graham and Ascher (1993) for approaching the problems of subsoil infertility, with particular reference to zinc. Field experiments with wheat and barley were established at Minnipa, on Eyre Peninsula in South Australia to investigate the effects of applying nutrients (principally zinc, nitrogen and phosphorus) to the subsoil to a depth of 0.4 m with a modified deep ripper. A deep pot experiment was designed to measure the zinc efficiencies (in terms of dry matter production) of a range of species grown in siliceous sand. The effects of added zinc on root growth were compared. A pot experiment was also designed to measure the effects of zinc placement in the soil on the zinc concentrations and uptake in Excalibur, particularly with respect to concentrations in grain.

Bibliography: leaves 290-324. / xxii, 324 leaves, [5] leaves of plates : col. ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis investigates two avenues suggested by Graham and Ascher (1993) for approaching the problems of subsoil infertility, with particular reference to zinc. Field experiments with wheat and barley were established at Minnipa, on Eyre Peninsula in South Australia to investigate the effects of applying nutrients (principally zinc, nitrogen and phosphorus) to the subsoil to a depth of 0.4 m with a modified deep ripper. A deep pot experiment was designed to measure the zinc efficiencies (in terms of dry matter production) of a range of species grown in siliceous sand. The effects of added zinc on root growth were compared. A pot experiment was also designed to measure the effects of zinc placement in the soil on the zinc concentrations and uptake in Excalibur, particularly with respect to concentrations in grain. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agronomy and Farming Systems, 1997

Three studies, two field and one laboratory, were performed to evaluate Cu or Cu and Zn from either sulfate sources or Cu-enriched pig manure. The studies were designed to investigate the effects of Cu and Zn in soils and corn (Zea mays L.). The first field study consisted of continuing a longterm field experiment which was established in 1967 to evaluate corn response and changes in a Davidson clay loam soil to yearly additions of Cu and Zn sulfates. In 1983, the 17 annual additions of Cu and Zn resulted in cumulative totals of 280 kg Cu and 560 kg Zn ha⁻¹. These Cu and Zn additions, either alone or together, did not cause any grain or stalk yield decreases. The DTPA extractant effectively separated all soil treatment levels for both Cu and Zn. Copper concentrations in the blades and grain were not related to soil additions of Cu or Zn. However, Zn concentrations in blades and grain were directly related to each other, r=0.87**, to soil Zn treatment levels and to DTPA extractable Zn. The second field experiment was designed to evaluate the effects of soil application of Cu-enriched pig manure and CuSO₄ on corn. The five treatments in each of three field locations consisted of a control, low and high Cu-enriched pig manure levels, and Cu, as CuSO₄, equivalent to Cu amounts in the manure. The soils varied in texture from clay loam to fine sandy loam, and ranged in CEC from 5 to 12.3 cmol(+) kg⁻¹. Copper-enriched pig manure, containing 1285 mg Cu kg⁻¹, was produced by pigs fed diets supplemented with 242 mg Cu kg⁻¹. After six years, 198 mg Cu kg⁻¹ had been applied by the high treatments. The DTPA extractable Cu was not related to leaf nor grain Cu levels but was linearly related, r=O.95**, to applied Cu. No nutrient deficiencies or toxicities were observed. The third study was a laboratory incubation of added Cu. The 15 soils ranged from 54 to 489 mg kg⁻¹ in clay and from 5.4 to 7.4 in pH. Extractable Cu had simple correlations with five soil properties, clay, surface area, hydrous Al, hydrous Fe, and hydrous Mn. Three treatments, a control and 22 kg ha⁻¹ Cu as CuSO₄, and as Cu-enriched pig manure (equivalent to 975 mt wet manure ha⁻¹), were applied to the soils at 33 k Pa moisture. Copper was extracted in the following order for the control and CuSO₄, treatments: AlCl₃ in O.5M HC1 > EDTA > DTPA. A different order of Cu extraction occurred for the Cu-enriched pig manure treatment such that EDTA > DTPA > AlCl₃ in 0.5M HC1. Extractable Cu decreased with time regardless of Cu source. / Ph. D. / incomplete_metadata

[Truncated abstract] Zinc deficiency in crops is the most widespread micronutrient deficiency, with about 50% of the cereal-growing areas worldwide containing low levels of plant-available Zn. Zinc plays multiple key roles in different metabolic and physiological processes; its deficiency in crops reduces not only grain yield, but also the nutritional quality of grains. Insufficient micronutrient intake, particularly Zn and Fe, afflicts over 3 billion people in the world, mainly in developing countries. Increasing the amount of Zn in food crops can contribute to improving the Zn status of people. Furthermore, Zn-dense seeds have agronomic benefits, resulting in greater seedling vigour, bigger root system and higher crop yield when sowed to soils with low plant-available Zn. Enhancing nutrient content and nutritional quality of crops for human nutrition is a global challenge currently, but it was mostly ignored during the breeding process in the past. There is a significant genotypic variation for seed Zn accumulation in several crops (including barley) which could be exploited in the breeding programs to produce genotypes with higher seed Zn concentration and content. However, the progress in Zn efficiency until now has mainly relied on conventional plant breeding approaches that have had limited success. Therefore, reliable alternative methods are required. Enhancing mineral nutrition through plant biotechnology may be a sustainable and beneficial approach in developing Zn-dense seeds in the staple crops. ... This DNA band was sequenced and converted into a simple sequence-specific PCR-based marker, which was designated as SZnR1 (seed Zn-regulator1). The developed marker is very easy to score, is inexpensive to run and amenable for a large number of plant samples. The successful development of SZnR1 molecular marker linked to chromosome region associated with seed Zn concentration and content using MFLP in this study illustrates the advantage of this technique over some other DNA fingerprinting methods used for identification of molecular markers for marker-assisted selection (MAS). In conclusion, the greater Zn efficiency of Sahara over Clipper under sufficient Zn supply may be attributed to its higher uptake of Zn. It appears that soil-based pot experiments under controlled condition may offer potential improvements over field experiments in screening for seed Zn accumulation. Shoot and seed Zn concentration and content can be used to diagnose the Zn statues of barley genotypes, and may be a useful selection criterion for Zn efficiency in large populations like doubled-haploid populations aimed at developing molecular markers for Zn efficiency. Identified QTLs influencing seed Zn concentration were repeatable in the field and glasshouse conditions, suggesting their robustness across environments as well as their value in marker-assisted selection. The developed PCR-based marker SZnR1 and other molecular markers associated with the QTLs on the short and long arms of chromosome 2H have the potential to be used for marker-assisted selection in breeding for Zn-dense seed in barley.

Copies of author's previously published articles inserted. Bibliography: leaves 195-230. In this study the soil aqueous phase chemistry of Zn and Cu in alkaline sodic soils are investigated. The chemistry of trace metal ions at indigenous concentrations in alkaline sodic soils are reported. Metal ions at low concentrations are measured by the graphite furnace atomic absorption spectrometry (GFAAS) technique.

Copies of author's previously published articles inserted. / Bibliography: leaves 195-230. / xx, 320 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / In this study the soil aqueous phase chemistry of Zn and Cu in alkaline sodic soils are investigated. The chemistry of trace metal ions at indigenous concentrations in alkaline sodic soils are reported. Metal ions at low concentrations are measured by the graphite furnace atomic absorption spectrometry (GFAAS) technique. / Thesis (Ph.D.)--University of Adelaide, Dept. of Soil Science, 1998