Multi-stage formation of REE minerals in the Palabora Carbonatite Complex, South Africa

Aims: Maize is of great significance in the national food security of South Africa. Maize production levels in South Africa continue to decline, further deteriorating the situation of increased food insecurity, unemployment and increased poverty levels in the face of increasing population. This paper investigated fundamental variables influencing maize yield in the South African major maize producing regions. Study Design: A multi-stage stratified sampling method was employed to select maize producing farmers in the major maize producing provinces, namely Mpumalanga, Free State and North West provinces of South Africa. Furthermore, three districts were selected from which maize farmers were then selected. Methodology: Using linear multiple regression for a sample of 202 maize farmers, maize yield as a dependent variable was regressed against land size, fertilizer usage, labour, herbicides and seeds as independent variables. The paper employed the Cobb-Douglas production function to estimate parameters. The data obtained from the field were subjected to analysis using inferential statistics using SPSS v20. Results: The study showed that fertilizer, labour, and herbicides used in the production of maize in the study area were positively and statistically significant at a 5% confidence interval (P<0.05) with elasticity coefficients of 0.55, 0.47 and 0.198 respectively. The independent variables computed in the model had positive elasticity coefficients indicating a direct positive relationship between the input variables and maize output. The study also revealed that farmers in the study area were applying fewer amounts of fertilizer than the recommended rates per hectare. Conclusion: The study recommends that the South African government should supply inputs to maize farmers at subsidized rates to promote correct application rates and attain higher yields. The promotion of good quality extension services to foster good agricultural practices in the production of maize is also recommended.

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AGRIBUSINESS CHALLENGES TO EFFECTIVENESS OF CONTRACT FARMING IN COMMERCIALIZATION OF SMALL-SCALE VEGETABLE FARMERS IN EASTERN CAPE, SOUTH AFRICA

Journal of Agribusiness and Rural Development ◽

10.17306/j.jard.2018.00429 ◽

2018 ◽

Vol 50 (4) ◽

Author(s):

Musa Khapayi ◽

Pieter Van Niekerk ◽

Phillip Retief Celliers

Keyword(s):

South Africa ◽

Agricultural Practices ◽

Small Scale ◽

Eastern Cape ◽

Contract Farming ◽

Group Discussions ◽

Vegetable Farmers ◽

Multi Stage ◽

Frame Work ◽

Small Scale Farmers

The study investigated the key factors that influ- ence small-scale vegetable farmers’ participation in contract farming arrangements. A sample of 70 small-scale vegetable farmers and 15 key informants of agribusiness firms involved in contract farming production of vegetables were selected in Amathole and Sarah Baartman (formerly Cacadu) district municipalities in the Eastern Cape province of South Africa. Focus group discussions and in-depth interviews were chosen as data collection tools to identify the factors that influence small-scale vegetable farmers’ participation in contract farm- ing arrangements with agribusiness firms. The data was ana- lyzed using open multi-stage coding with an inductive frame- work approach. Atlas.ti was used to sort and organize data. The findings indicated availability of farm assets, hydrologi- cal conditions, farming skills and distance of producer to the markets as key determinants of contract farming participation. The use of unmarketable cultivars, inappropriate agricultural practices and inconsistent supply in quality and quantity of vegetables were found to be bottlenecks to contract participa- tion. The study recommends a more meaningful state support and incentives for agribusiness firms; otherwise, growth of small-scale farmers in contract farming is unlikely because of the financial implications for private sector companies.

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Performance and Operational Aspects of Biological Phosphate Removal Plants in South Africa

Water Science & Technology ◽

10.2166/wst.1983.0116 ◽

1983 ◽

Vol 15 (3-4) ◽

pp. 219-232 ◽

Cited By ~ 8

Author(s):

B H Paepcke

Keyword(s):

South Africa ◽

Dissolved Oxygen ◽

Activated Sludge ◽

Phosphorus Removal ◽

Nitrogen Concentration ◽

Air Entrainment ◽

Phosphate Removal ◽

Plant Performance ◽

Nitrogen And Phosphorus ◽

Multi Stage

A survey was undertaken of the operation and performance of eleven multi-stage activated sludge plants in South Africa designed for biological nitrogen and phosphorus removal. The results indicate that phosphorus removal has been consistently good in only one case, although several other plants have performed very well in recent months. The major factors adversely affecting phosphorus removal are excessive amounts of nitrate and dissolved oxygen in the anaerobic basins. Nitrate is introduced into the anaerobic basin in the return activated sludge when denitrification is incomplete. Incomplete denitrification is due to a disproportionately low amount of carbonaceous matter in the influent wastewater relative to the total nitrogen concentration. The dissolved oxygen is the result of air entrainment at the Archimedes screw return activated sludge pumps, at cascades in the influent and return sludge channels, and by vortices caused by the stirrers. Other factors which have significantly affected plant performance are mechanical problems, inadequate operator training, and insufficient sample analyses on which to base operating decisions. With due recognition paid to these problem areas, the performance of future designs should be much improved.

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Significance of diagenesis for the origin of Witwatersrand-type uraniferous conglomerates

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1979.0026 ◽

1979 ◽

Vol 291 (1381) ◽

pp. 277-287 ◽

Cited By ~ 18

Keyword(s):

South Africa ◽

Organic Matter ◽

Coarse Grained ◽

Uranium Deposits ◽

Multi Stage ◽

Ore Minerals ◽

History Of ◽

Diverse Origin ◽

Reducing Bacteria ◽

Petrographic Study

A petrographic study of pyrite may be the key to the understanding of the Witwatersrand (South Africa) gold-uranium deposits: the sediments of the Witwatersrand Supergroup contain at least nine types of pyrite, namely (1) Laminated pyrite seams; (2) pyrite nodules in shales; (3) pyrite nodules in quartzite and conglomerate; (4) pyrite as overgrowths on carbonaceous filaments; (5) pyrite filling pore spaces and replacing clasts; (6) pyrite replacing detrital magnetite; (7) allogenic fragments of laminated pyrite; (8) allogenic fragments of pyrite nodules; and (9) allogenic fragments of coarse-grained pyrite. Types 1-6 probably formed during diagenesis of the sediment due to the activity of sulphate-reducing bacteria; types 7 and 8 are transported fragments of diagentic pyrite; type 9 may be of diverse origin, but may also in part be transported fragments of diagenetic pyrite. Pyrite petrography suggests a multi-stage history of ore enrichment: diagenetic precipitation of gold, uraninite and pyrite in sediments containing organic matter, followed by erosion, transport of allogenic fragments of ore minerals for short distances, and concentration in lag gravels at channel bottoms and unconformities. Repeated cycles of weathering, diagenetic precipitation from weathering solutions, erosion, minor transport and redeposition may have caused the extraordinary enrichment of the ores on major unconformities in the Upper Witwatersrand Supergroup.

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