https://vital.seals.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://vital.seals.ac.za/vital/access/manager/Repository/vital:10743 Wed 12 May 2021 20:28:02 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9595 Wed 12 May 2021 19:27:29 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10480 Wed 12 May 2021 18:49:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10369 Thu 13 May 2021 14:50:54 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26433 0.3. The possibility that Si could become a DX-centre in AlxGa1-xN was then investigated. However, Hall effect measurements showed that the Si activation energy increased in good agreement with the model of a shallow effective mass state donor, with no sudden increase in ED being observed up to x = 0.4. It was then suggested that the increase in the E1 and E2 activation energies, as well as the exciton localisation energies, could be due to the 9 7 valence band crossover, which occurs at roughly the same composition. However, due to the scarcity of reports on the valence band structure in AlxGa1-xN no conclusions could be made at this stage as to the effect of the 9 7 valence band crossover on the PL properties of AlxGa1-xN.]]> Thu 13 May 2021 05:42:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10513 Thu 13 May 2021 04:13:15 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10548 Thu 13 May 2021 04:10:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:11079 Thu 13 May 2021 03:54:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10367 Thu 13 May 2021 02:38:45 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10368 99.9 % certainty) potential in two of the semi-organic mixtures formulated while the organic mixture showed a relatively good growth rate as compared to the control (pure tap water). According to statistical analysis (ANOVA) comparison, two of the semi-organic mixtures performed considerably better than the two commercial samples evaluated. Potential benefits profoundly associated with these nutrient mixtures as compared to similar liquid fertilizer products on the market is that most nutrients are chelated and dissolved in solution. Also, the mixtures contain all necessary nutrients including plant growth substances required for healthier plant growth. The most important socioeconomic impact is the value addition to the technology chain in the citrus industry. The use of fluid fertilizers in significant quantities is less than twenty years old. Nevertheless, growth has been so rapid that in South Africa demand for mixed liquid fertilizer has greatly increased from 90 000 tons NPK & blended micronutrients in 1955 to more than 600 000 per annum tons today (Report 41/2003, Department of Minerals and Energy). The liquid fertilizers market is sparsely specialized with major competitors like Omnia, Kynoch and Foskor supplying more than 50 % of the market demand. Amongst the nutrient mixtures formulated, mixture one is an NPK (1-1-2) based nutrient mixture containing both secondary nutrients (0.5 % Mg & 1.0 % Ca) and seven micronutrients (0.1 % Fe, 0.05 % Cu, 0.05 % Zn, 0.05 % Mn, 0.02 % B, 0.0005 % Mo and 0.0005 % Co). The composition of this mixture offers the formula a potential to be used as a general purpose (all stages of plant growth) fertilization mixture in view of its balanced composition (containing all essential plant nutrients). Mixture two contains essentially the micronutrients and in higher concentrations (0.3 % Fe, 0.3 % Cu, 0.1 % Zn, 0.2 % Mn, 0.02 % B, 0.0005 % Mo and 0.0005 % Co) as compared to mixture one except for boron, molybdenum and cobalt. The concentration of the micronutrients contained in this mixture is adequately high which offers a potential for it to be used in supplementing nutrition in plants with critical micronutrient-deficient symptoms. Mixture three is very similar to mixture two (1.0 % Fe, 0.05 % Cu, 0.05 % Zn, 0.05 Mn, 0.05 % B, 0.0005 % Mo and 0.0005 % Co) except that the concentrations of all seven micronutrients are considerably less than those of contained in mixture two. However, the concentration of iron in this mixture is as high as 1.0 %. The mixture has a potential to be used in high iron-deficient situations. Mixture four is an organic formula with relatively low nutrient concentrations (NPK-0.02-0.02-1, 0.27 % Mg, 0.02 % Ca, 0.008 % Fe, 0.26 % Cu, 0.012 % Zn, 0.009 % Mn). Nevertheless, this mixture is appealing for organically grown crops where the use of chemicals is prohibited by standards. These lemon juice-based nutrient mixtures were further characterized and tested for stability and storability over a period of eight weeks. This study revealed no major change in the physical quality (colour, pH and “salt out” effect). The basic formulation methodology is a two-step procedure that involves filtration of the lemon juice to remove membranous materials, mixing at ambient temperature and stabilization of the nutrient mixtures. However, for the organic nutrient formula mix, filtration follows after extraction of nutrients from plant materials using the lemon juice.]]> Thu 13 May 2021 01:15:13 SAST ]]>