http://hdl.handle.net/10386/982 Theses and Dissertations (Biology) Sun, 05 Apr 2026 17:45:43 GMT 2026-04-05T17:45:43Z http://hdl.handle.net/10386/5347 Geology, geochemistry and occurrence of rare earth elements in coal from the Soutbansberg West Coalfield (Mopane Sector). Limpopo Province, South Africa Ntake, Mahlatse Manthepeng The supply security of rare earth elements (REE) is a global key concern due to their scarcity and increasing demand. Consequently, the quest for alternative sources of REE is pivotal for countries that are reliant on REE imports, including South Africa. This search for new alternative non-conventional sources of these critical elements has sparked a heightened interest in coal deposits as the new alternative source. The Soutpansberg Coalfield of South Africa hosts substantial coal deposits. However, there is a gap in understanding the geology and geochemistry of the coals as well as the rare earth-bearing potential of this coalfield. Therefore, this study aims to investigate the geology, geochemistry and occurrence of rare earth elements in the coal stockpiles within the Mopane Sector of the Soutpansberg Coalfield. To fulfil the purpose of this study, coal petrography, proximate analysis, ultimate analysis, x-ray diffraction, scanning electron microscopy-energy dispersive spectrometry and inductively coupled plasma-mass spectrometry were used. Most of the coal stockpiles were ranked as high-volatile bituminous B-A coals distinguished by their high vitrinite, moderate to low liptinite and low inertinite macerals. Geochemically, the coals contained low moisture content with high ash yields and moderate volatile matter. Additionally, the coals contained low sulphur with high oxygen and carbon contents, corroborating their coke properties. The mineralogical analysis of the coals confirmed that the coals were predominantly composed of organic carbon (24% to 73%), quartz, kaolinite, plagioclase, siderite and other minerals. These coal stockpiles were further confirmed to contain the renowned rare-earth bearing minerals, including xenotime and monazite, associated with clay, quartz and other minerals. Several REE were detected within the samples, including Er, Tm, Ho, Gd, Yb, Lu, Sm, Eu, Tb, Pr, Dy, Nd, Ce, La, Sc, and Y, with the predominant REE being Ce. The total REE within each stockpile varied between 230 ppm and 670 ppm, with the stockpiles being enriched in light REE (2166.67 ppm) and depleted in heavy REE. Furthermore, the coal stockpiles exhibited high yields of excessive REE compared to the critical and uncritical REE. The stockpiles are of a sedimentary source with felsic and terrigenous associations. Ce and Eu anomalies suggest that the enrichment of the coals is of a detritic origin, which might be from the Limpopo Mobile Belt and the Beit Bridge Complex. The normalized REE concentrations of the samples were compared with those of Chinese, USA, UCC and MKB coals and they were found to be higher than all the aforementioned deposits. In addition, the coals fall within the promising regions for the economic extraction of the REE. Thesis (M. Sc. (Geology)) -- University of Limpopo, 2025 Mon, 01 Jan 2024 00:00:00 GMT http://hdl.handle.net/10386/5347 2024-01-01T00:00:00Z http://hdl.handle.net/10386/4836 Effects of maize and legume intercropping system on soil nitrogen dynamics and crop growth Mmotong, Mmabopele Mokgethoa Nitrogen is an essential mineral nutrient that can hinder crop production if not managed properly. Improved agricultural management practices such as cover cropping, crop rotations or intercropping influence nitrogen availability and supply. Hence this study was aimed at investigating how intercropping cereal with legume influences (i) soil nitrogen dynamics and (ii) selected growth and yield parameters. A field experiment was carried out at the University of Limpopo experimental farm (Syferkuil) integrating maize (Zea mays) with chickpea (Cicer arietinum) and mungbean (Vigna radiata) under two different moisture regimes (irrigated and rainfed). The experimental site was a split plot design replicated three times. The treatments were as follows: Sole maize- SM, Sole chickpea- SC, Sole mungbean- SMB, Maize/chickpea intercropping- MC, Maize/mungbean intercropping– MMB under rainfed and irrigated moisture regimes. Soil fertility variables i.e., bulk density, aggregate stability, pH, phosphorus and organic carbon; and nitrogen fractions: biological nitrogen fixation (BNF), mineralisation, uptake, residual and leaching were measured using standard procedures. Data analyses was done using the GenStat 20th Edition software. The study showed insignificant interaction effect between cropping system and irrigation regime did not have a significant effect on soil conditions bulk density, aggregate stability, pH, organic carbon (p>0.05). Nitrogen mineralisation was higher in the intercrops in comparison to the sole grown crops. Biological nitrogen fixation (BNF) was higher in the irrigated plot compared to the rainfed plot. Chickpea generally fixed a greater amount of nitrogen compared to mungbean. Chickpea showed greater nitrogen fixation in the intercropped stand while mungbean had a higher BNF in the sole stand. The uptake of nitrogen was greater in the irrigated compared to the rainfed plot. Sole maize had the highest nitrogen uptake, followed by the intercropped stands and then the sole legume stands. Residual nitrogen was greater in the rainfed plot compared to the irrigated plot. Intercropping both legume crops resulted in higher residual nitrogen compared to the sole stands. Mineral nitrogen leached beyond the active root zone was greater in the irrigated plot. The intercropped stands recorded lower mineral nitrogen leached in comparison to the sole stands. Data collected to observe growth and yield parameters were chlorophyll content, leaf area plant height and plant biomass. The results depicted a positive response to intercropping through the chlorophyll content and leaf area. Plant biomass was higher in in the sole stands for all associated crops. In conclusion, cereal/legume intercropping can be a sustainable approach to maximizing nitrogen use efficiency while minimizing potential losses. Thesis (M.Sc. (Soil Science)) -- University of Limpopo, 2024 Mon, 01 Jan 2024 00:00:00 GMT http://hdl.handle.net/10386/4836 2024-01-01T00:00:00Z http://hdl.handle.net/10386/4433 The abundance and species richness of the spiders (Arachinda: Aranae) associated with open savanna, woodland and false grassland in the Polokwane Nature Reserve, Limpopo Province Modiba, Mokgadi Asnath Lack of professional expertise on the taxonomy and systematics of invertebrates in the country leads to significant problems in understanding the invertebrate biodiversity and causes under appreciation of species. Little knowledge exists about the diversity of arachnids in certain eco regions. South Africa is obliged to develop a strategic plan for the conservation and sustainable use of biodiversity since meaningful conservation cannot take place if the involved species are not known. The South African National Survey of Arachnida (SANSA) was initiated to make an inventory of the arachnid fauna of South Africa. Various projects are underway to prepare inventories of the spider fauna of the different floral biomes and provinces. Surveys of arachnid fauna are more important in conserved areas as conservation strategies are already in place. As part of SANSA, a study was initiated in the Polokwane Nature Reserve during March 2005 until the end of February 2006 to determine the species richness and diversity of spiders associated with Acacia tortillis Open Savanna, Acacia rehmanniana Woodland and the Pietersburg Plateau False Grassland at the Polokwane Nature Reserve in the Limpopo Province. This is the first survey in the area and provides information to SANSA in terms of conserved areas in the Savanna Biome. During this study four sampling methods (sweep netting, tree beating, active searching and pitfall trapping) were used to collect spiders from all the different vegetation layers. They were identified to morpho-species and a checklist of spiders collected was compiled, adding data to the Limpopo Province check list. The composition of the spider community, seasonal abundance patterns, fluctuations and the influence of vegetation structure on spider populations were determined. A total of 7 776 spiders were caught belonging to 33 families, 131 genera and representing 219 species. Of these species, 153 (69.8 %) were wanderers and 66 (30.2 %) web-builders. The Oxyopidae was the most abundant family (1575), followed by Eresidae 1 554), Thomisidae (1 411), Araneidae (582), Lycosidae (568) and Salticidae (527). The Araneidae was the most species rich family (33) followed by the Thomisidae (31), Salticidae (25), Gnaphosidae (20), Theridiidae (18), Lycosidae (16) and the Philodromidae (12). The seven most abundant species collected during this study were Stegodyphus dumicola (Eresidae) (1 549) followed by two oxyopids, an undescribed oxyopid Oxyopes sp.3 (535) and Oxyopes russoi (476), Runcinia flavida (Thomisidae) (437), another oxyopid Oxyopes pallidecoloratus (384) followed by a lycosid Evippomma squamulatum (282) and another thomisid Monaeses austrinus (201). Immature specimens dominated captures, while females and males peaked during December till March with the most diverse species found in April. The highest specimen numbers and species richness was caught in the Woodland site (3 520; 173) followed by the Open Savanna (2 823; 159) and the Grassland site (1 433; 115). The Shannon-Weiner diversity index value calculated for species caught in the three different sampling sites was the highest for the Open Savanna site (H’=3.777), followed by the Woodland site (H’=3.569) and the Grassland site (H’=3.273). During this study the highest number of specimens were caught by sweep netting (2 972), followed by active searching (2 572), tree beating (1 895), pitfall trapping (323) and only a few (14) were caught by one attempt of leaf litter sifting. High evenness values for the Open Savanna (HE=0.748), the Woodland (HE=0.692) and the Grassland sites (HE=0.689) indicated a relatively even distribution of species across these sites. The Bray-Curtis similarities calculated for the methods used to catch species occurring on the three sites was 48 % similar for species caught by sweep netting and tree beating. Species caught by active searching and pitfall traps were 44 % similar. Additionally the species caught by leaf litter sifting were only 8 % similar to that caught using the other four methods. Vegetation structure and the time of year influenced the spider community at the Polokwane Nature Reserve. Temporal changes influenced the species richness, diversity as well as the number of mature, identifiable specimens. No work have previously been undertaken in this area and the species collected represent new distribution records for all species collected.The present study made an important contribution towards increasing our knowledge of spider diversity in the Savanna Biome. Thesis (M.Sc. (Biodiversity )) -- University of Limpopo, 2007 Mon, 01 Jan 2007 00:00:00 GMT http://hdl.handle.net/10386/4433 2007-01-01T00:00:00Z http://hdl.handle.net/10386/3276 Adaptation of smallholder maize farmers to temperature and rainfall variability in Capricorn District Municipality, Limpopo Province, South Africa Mazwi, Kabelo Makadikwe Refer to document Thesis (M. Sc.) -- University of LImpopo, 2019 Tue, 01 Jan 2019 00:00:00 GMT http://hdl.handle.net/10386/3276 2019-01-01T00:00:00Z