Agriculture and Environmental Science

The ecological status of Hout River Dam was evaluated in 2011 by assessing fish health, based on condition factor (K), health assessment index (HAI) and inverted parasite index (IPI), which provided a simple and rapid means of establishing the health of fish. Surveys were conducted during summer, winter and spring 2011. To verify results, water quality was analysed during each survey. Clarias gariepinus, Oreochromis mossambicus and Cyprinus carpio were collected using conventional angling gear and gillnets. Mean K values of 0.6, 2.0 and 1.4, and HAI scores of 38, 41 and 35, were recorded for each species, respectively. The metrics that correlated best with fish health scores were haematocrit values and ecto-and endoparasite indices. Differences in K, HAI, and HAI using IPI determinations, were insignificant (p > 0.05) between species, while water contaminants, with the exception of ammonium (NH 4 ), nitrate (NO 3 ) and aluminium (Al) concentrations in summer, fell within the levels stipulated by the South African target water quality range guidelines for aquatic ecosystems. It was thus inferred that the dam was in a good ecological state.

The expansion of the kiwifruit industry in South Africa has led to increasing demand in the new improved species, Actinidia arguta and Actinidia chinensis, with smaller and sweeter fruits than the commonly grown Actinidia deliciosa. Seed dormancy had been an obstacle in the successful seedling establishment of the two Actinidia species thus, the effect of gibberellic acid (GA3) and cold stratification (CS) on in vivo seed germination was studied. In the GA3 experiment, non-stratified seeds were imbibed in dH2O (control) and GA3 solutions (500, 1000, 2000 and 2500 ppm) for 24 h at ambient temperature. For the CS experiment, seeds of both species were stratified on moist filter paper at 4°C for 14, 28, 42 and 56 days, while seeds kept at ambient temperature served as a control. Seeds from different GA3 and CS treatments were sown in seedling trays filled with moistened vermiculite and kept under controlled conditions. Data on seedling performance variables, namely, germination percentage (GP), mean germination time (MGT), germination rate (GR) and germination index (GI) were subjected to ANOVA and then lines of the best fit. Imbibing kiwifruit seeds for 24 h in solutions of different GA3 concentrations resulted in no germination of A. arguta seeds and a very poor germination (1%) of A. chinensis seeds. In the cold stratified seeds, treatment effects were significant (p≤0.05) in A. chinensis, except for A. arguta seeds. In A. chinensis, the optimum CS duration and performance values were 37 days and 16% for GP, 34 and 15 days for MGT, 33 days and 0.04 seedling day-1 for GR and 39 days and 0.13 seedling day-1 for GI, respectively. Results of this study suggested that GA3 had no positive effect, whereas CS had a promising effect on in vivo seed germination in both Actinidia species.

Environmental assessments and authorisations surrounding project level developments are often made in isolation, without consideration of the regional or strategic context within which individual developments are done. This research investigates the quality of Environmental Management Frameworks (EMF) as strategic environmental instrument. EMF is a unique South African instrument that was first conceptualised in 1989, enacted in 2006 and updated in 2010. EMFs were developed to map environmental sensitivity to aid the screening out of undesired developments in sensitive environments and to minimise unnecessary project level assessments in preferred development areas. EMFs form an important link between environmental assessment (EA) processes and planning strategies such as Spatial Development Frameworks (SDFs) and

Environmental assessments and authorisations surrounding project level developments are often made in isolation, without consideration of the regional or strategic context within which individual developments are done. This research investigates the quality of Environmental Management Frameworks (EMF) as strategic environmental instrument. EMF is a unique South African instrument that was first conceptualised in 1989, enacted in 2006 and updated in 2010. EMFs were developed to map environmental sensitivity to aid the screening out of undesired developments in sensitive environments and to minimise unnecessary project level assessments in preferred development areas. EMFs form an important link between environmental assessment (EA) processes and planning strategies such as Spatial Development Frameworks (SDFs) and Integrated Development Plans (IDPs), due to their spatial output of environmental sensitivity maps and their ability to feed strategic assessment processes required by SDFs. They have a legal mandate which ensures their assimilation and use. This research uses a multiple case study approach to review seven EMF documents for their quality. The quality aspects identified are the process, methodology and documentation components, using the printed EMF documentation as primary information source. Quality review criteria were subsequently developed to investigate these inputs, using the legal mandate of EMF as basis. Each case was rated for compliance with the quality criteria using a six-level rating schedule. Further analyses were made by comparing the performance of cases against one another. Public participation emerged as the weakest component of EMF practice, while aspects of sensitivity analysis also performed weaker than other aspects. More focus is required on aligning scales and resolutions of map inputs, mapping methods and general integration of spatial data, especially those of adjoining districts. The need to substantiate a rationale for buffer determination also requires further refinement. The practice of conducting EMF is well established and it can be valuable in sustainable development planning and decisionmaking. Recommendations to enhance the sustainability outcomes and hence effectiveness of this instrument are made, as well as future research objectives for increasing its utility.

Titanium is produced commercially by the Kroll process, which involves the magnesiothermic reduction of titanium tetrachloride (TiCl4). However, this is not suitable for developing a continuous reduction process. Recently, there have been attempts to develop a new continuous titanium production process by magnesiothermic reduction of other subchlorides such as titanium trichloride. In this study, the DL_POLY code was employed to investigate the influence of temperature on TiCl3 (α, β, γ). We found that the γ-phase is ordered, and all phases are spontaneous at 50-2000 K. The order of stability is β> α> γ, in agreement with other reported work. These findings suggest that TiCl3 might be used as a potential medium in the titanium production process.