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| Registros recuperados: 14 | |
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| Viljoen, Machiel F.; Dudley, N.J.; Gakpo, E.F.Y.. |
| Information on the value of water in use is a prerequisite for the efficient allocation, utilization, trading and transfer thereof. These issues are becoming very important for South Africa. Linear programming (LP) and stochastic dynamic programming (SDP) are two techniques that can be applied to value water. Based on a simulated irrigation farming situation downstream of the Vanderkloof Dam wherein farmers hold a capacity share (CS) this paper draws a comparison between the marginal value products (MVP’s) obtained from applying LP and SDP simultaneously. Linear programming is used to optimize water use on the farm during the immediate season while SDP is used to optimize the use of water in storage in the farmers capacity share (CS) in the Vanderkloof Dam... |
| Tipo: Journal Article |
Palavras-chave: Resource /Energy Economics and Policy. |
| Ano: 2000 |
URL: http://purl.umn.edu/54209 |
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| Gakpo, E.F.Y.; Tsephe, J.; Nwonwu, F.; Viljoen, Machiel F.. |
| This study attempts to arrive at an optimal allocation of irrigation water using capacity sharing (CS) as an institutional arrangement, and stochastic dynamic programming (SDP) as an optimisation model. It determines the value of an additional unit of water under a crop enterprise mix of lucerne-maize-wheat (LMW). SDP is an improvement on linear programming (LP) under stochastic conditions. The SIM-DY-SIM Model was used to simulate optimal returns, decision and policy variables under varying conditions of capacity share. LP results show that wheat has the highest MVP of R0.39/m3, with maize exhibiting the lowest value of R0.09/m3. The MVPs generated with SDP range between R0.06/m3 and R0.35/m3 on the whole farm basis, with revenue to the farmer increasing... |
| Tipo: Journal Article |
Palavras-chave: Resource /Energy Economics and Policy. |
| Ano: 2005 |
URL: http://purl.umn.edu/31704 |
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| Viljoen, Machiel F.. |
| The paper focuses on improvement in access to the natural resources land and water to bridge the economic divide in South African agriculture. The relevance of the approach to bridging the economic divide, progress made since 1994 in land and water reform and problems experienced and strategies to overcome them are discussed. Challenges imposed by climate change and biodiversity on the effective utilization of land and water resources are also highlighted. Given the broadness of the subject, an overview of some important issues can only be attempted within the allocated time. The presentation starts with background information to place the discussion in context within the national framework and to define certain concepts. Conceptual issues regarding... |
| Tipo: Journal Article |
Palavras-chave: Land Economics/Use; Resource /Energy Economics and Policy. |
| Ano: 2006 |
URL: http://purl.umn.edu/31733 |
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| Baiphethi, Mompati N.; Viljoen, Machiel F.; Kundhlande, Godfrey. |
| Thaba Nchu is a semi-arid area with low and erratic annual rainfall not exceeding 600mm. Various dryland crops are produced with relatively low yields and high risk of failure. Lack of appropriate technology and other constraints has led to most of the arable land being unused thus restricting agribusiness opportunities in an area where unemployment and food insecurity are thriving. Rainwater harvesting has a huge potential to increase crop yields in Thaba Nchu and reduce the risk of losses, and thus improve food security and enhance sustainability. Different in-field rainwater harvesting (IRWH) techniques have been tested and applied at Glen and Thaba Nchu. This paper gives comparative results for three crops produced with regard to relative... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Land Economics/Use; Resource /Energy Economics and Policy; Risk and Uncertainty. |
| Ano: 2003 |
URL: http://purl.umn.edu/19076 |
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| Yakob, M.T.; Viljoen, Machiel F.; Jooste, Andre; Graz, M.. |
| In an effort to gain a better understanding of the trade in fish products by South Africa a starting point is examining South Africa's current trade in fish products. Useful tools in this regard, the Gini-coefficient, used to examine the degree of concentration for fish exports, and the intra-industrial trade coefficient (IIT), and used to examine the balance of international fish trade by South Africa. The Gini-coefficient for fish exports shows that fish export by South Africa is highly concentrated. The trend in concentration appears to have remained constant, and therefore the South African fisheries industry may boast a competitive advantage. However, cognisance should be taken of the fact that such a high level of concentration may render the South... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: International Relations/Trade. |
| Ano: 2006 |
URL: http://purl.umn.edu/25736 |
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| Viljoen, Machiel F.. |
| Utilising insights gained from a literature study about the social, economic and political impacts of irrigation droughts, research done on the impacts and management of floods and water restrictions in South Africa as well as analysing the disaster management policy process in South Africa since 1994, this presentation endeavours to present some guidelines for policy and strategy development with regard to the effective management of floods and droughts. In compiling this contribution extensive use has been made from a paper presented at a workshop of the ICID Working Group on Irrigation under Drought and Water Scarcity, Tehran, by G.R. Backeberg and M.F. Viljoen. |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Resource /Energy Economics and Policy. |
| Ano: 2003 |
URL: http://purl.umn.edu/28071 |
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| Symington, H.M.; Viljoen, Machiel F.. |
| Optimum management strategies (crop rotation systems, crop areas, irrigation intensities and moveable capital replacement) for typical one, two and three plot farmers at Vaalharts were determined under different intensities and incidences of water limitations as well as with increased water quotas and peak canal deliverances. Special consideration was given to changes needed in management strategy as well as the ability of the different typical farmers to survive financially as availability of water changes. The study utilised, inter alia, dynamic linear programming, water production functions and loss functions. The results indicate significant changes in optimum management strategies as water limitations, water quotas and peak canal deliverance change.... |
| Tipo: Journal Article |
Palavras-chave: Farm Management; Resource /Energy Economics and Policy. |
| Ano: 1997 |
URL: http://purl.umn.edu/54913 |
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| Baiphethi, Mompati N.; Viljoen, Machiel F.; Kundhlande, Godfrey; Botha, J.J.; van Rensburg, L.D.. |
| The paper investigates the impact of employing in-field rainwater harvesting (IRWH) production techniques on household food security for communal farmers in Thaba Nchu, by estimating the minimum area of land that a representative household needs to cultivate in order to meet its requirements. First, using a poverty datum line for South Africa, annual income required by an average household for food and other basic necessities (shelter and clothes) is calculated, given a specific level of non-farm income for a typical household in the study area. Second, the caloric requirement for an average household's is estimated by using the daily caloric requirement of each member of the household. The household uses its income from non-farm sources to purchase food... |
| Tipo: Journal Article |
Palavras-chave: Food Security and Poverty. |
| Ano: 2006 |
URL: http://purl.umn.edu/31741 |
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| Jirgi, A.J.; Ogundeji, Abiodun A.; Viljoen, Machiel F.; Adiele, M.A.. |
| The study examined the profitability and resources-use efficiency of millet/cowpea mixed farmers production in Niger state Nigeria. The primary data for the study was obtained using structured questionnaire administered to 80 randomly sampled farmers in Kotangora Local Government Area of Niger State. Farm budgeting technique and exponential production function were used to analyze the data. The results showed that the estimated gross margin, net farm income, gross ratio, operating ratio and returns on investment are N57,542.42 per hectare, N54,240.40 per hectare, 0.37, 0.31 and 2.15. The regression result shows that seed and family labour were statistically significant at 1% level of probability, while farm size and hired labour were statistically... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Crop Production/Industries. |
| Ano: 2010 |
URL: http://purl.umn.edu/113786 |
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| Viljoen, Machiel F.. |
| Time constraints limits this paper to giving a brief overview of a selection of only the most important events on the policy front. The aim is to set the stage for the conference by giving a synoptic overview of South African agricultural policy between 1994 and 2004. To put the policy development in historical and developmental perspective, relevant pre-1994 realities will be mentioned first. After outlining the policy development between 1994 and 2004, the presentation concludes with some 2004 realities and a perspective on the relevance of agricultural economics as a discipline. |
| Tipo: Journal Article |
Palavras-chave: Agricultural and Food Policy. |
| Ano: 2005 |
URL: http://purl.umn.edu/31715 |
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| Solomon, Mompati; Viljoen, Machiel F.. |
| Adhering to planning ethics is especially relevant when flood control planning of communities who settled in flood plains is at stake. Soweto-On-Sea (SOS) is an informal settlement in the flood plain of the Lower Chatty River near Port Elizabeth. As part of a research project which compared palaeoflood and conventional flood hydrology in the planning of flood control measures for SOS within a Cost Benefit Analytical (CBA) framework attention was also given to some ethical considerations. This paper, inspired by the conduct, rules and principles that govern the informal settlement of SOS evaluates some flood plain development and planning issues with a code of ethical conduct for planners and comes up with explanations for "unethical" conduct of and... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Community/Rural/Urban Development; Land Economics/Use. |
| Ano: 2003 |
URL: http://purl.umn.edu/19091 |
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| Armour, R.J.; Viljoen, Machiel F.. |
| Irrigation farmers in the lower reaches of the Vaal and Riet Rivers are experiencing substantial yield reductions in certain crops and more profitable crops have been withdrawn from production, hypothesised, as a result of generally poor but especially fluctuating water quality. In this paper secondary data is used in a linear programming model to test this hypothesis by calculating the potential loss in farm level optimal returns. The model is static with a time frame of two production seasons. Linear crop-water quality production functions (Ayers & Westcot, 1983; adapted from Maas & Hoffmann, 1977) are used to calculate net returns for the eight most common crops grown. Results show optimal enterprise composition under various water quality... |
| Tipo: Journal Article |
Palavras-chave: Crop Production/Industries; Resource /Energy Economics and Policy. |
| Ano: 2000 |
URL: http://purl.umn.edu/56171 |
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| Registros recuperados: 14 | |
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