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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

The role of irrigation policies in expanding irrigated food production in Mozambique.

Gêmo, Hélder R. January 2012 (has links)
In recognition of the crucial role irrigation plays in stabilizing agriculture production in the face of erratic rainfall that often affects Mozambique, the Government has, since national independence in 1975, implemented several policies regarding irrigation development. Yet, the country is still struggling to expand the area equipped for food crop irrigation. In particular, the formulation and implementation of irrigation policies has faced constraints in the expansion and effective use of irrigated land to ensure increased food production. Despite this, there has not been a systematic effort to consistently document and identify constraints and enablers of irrigation policies and development in to support evidence-based policy dialogue and interventions. This study intends to fill this gap. It does this through an analytical historical trajectory of the irrigation subsector, paying particular attention to critical factors affecting the effectiveness of irrigation policies in contributing to the expansion and effective use of irrigated land to enhance agriculture’s contribution to food production and food security in Mozambique. A qualitative approach is employed in which a review of the existing literature and official documents, along with secondary data collection, is augmented with interviews of key informants and expert opinions. The analysis posits that the ability of irrigation policies to effectively contribute to an expansion and improvement of irrigated production can be enhanced through addressing issues of policy weaknesses, limited investment resources to expand irrigated land, inadequate public institutional support to the irrigation subsector, especially at field level, limited involvement of the private sector in irrigation, weak farmers’ organizations (FOs) and water users associations (WUAs) on irrigated land as well as weak information and knowledge generation and sharing among relevant stakeholders. These issues are particularly pertinent in light of the anticipated implementation of the 2010 Irrigation Strategy. The role, cooperation and partnerships among Government, private sector, FOs/WUAs and development partners need to be taken into account in the formulation and implementation of public irrigation policies. Overall, it is important to note that the success of irrigation depends critically on other agriculture sector-wide policies, suggesting that it is important to have a comprehensive agricultural development policy in place. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.
22

Water irrigation costs and farm outputs : a case of selected crops in Limpopo Province

Dandane, Khutso Donald January 2022 (has links)
Thesis (M. Com. (Accounting)) -- University of limpopo, 2022 / Water scarcity is a problem for many countries across the world. Limpopo Province is no exception, as the province has regions that are arid and/or semi-arid. The accessibility of water and the management of water is amongst the critical issues faced by some of the rural farmers in the Limpopo Province. The challenge of inappropriate and inefficient use of modern irrigation technologies is associated with the exorbitant investment and operation costs, resulting in poor irrigation practices by smallholder farmers in the province, mainly affecting the production of citrus, avocado, nuts, potatoes and tomato production resulting in reduced yields and revenues. The study conducted a case study on the selected crop in the Limpopo Province, which included crops such as citrus, nuts, avocados, potatoes and tomatoes. The objectives of the study are to examine the influence that investments in water irrigation infrastructure has on the volume of farm yield, as well as to examine the influence of the cost of water irrigation systems on the volume of farm yield on the selected crops. The study used a survey research design, together with a mixed-method approach, whereby 50 farmers were purposively sampled in the Limpopo province. Primary data were collected from a focus group discussion and the administration of a questionnaire. A multivariate analysis was used to analyse the data. Out of 50 farmers, only 48 responded, which is a 96% response rate. From the analysis, the study found that investment in water irrigation has a positive and significant influence on the farm yield at a 0.01 confidence level. Furthermore, the OLS regression shows that a positive and significant relationship exists between the total cost index for Citrus and the farm yield. The total cost index has a varying effect on the distribution of farm yield. It is expected that an increase in the level of education will increase revenue. Overall, the industry may also need to look at the introduction of hybrid systems that are more cost-effective, that take advantage of solar and wind energy. Future research can look at the different crops in different provinces of South Africa. / Kagiso Trust
23

Total evaporation estimation from sugarcane using the scintillation technique.

Wiles, Luke Wilson. January 2006 (has links)
Ongoing concerns about the efficient and sustainable utilisation of South Africa’s water resources have resulted in much interest regarding the water use of different land uses within a catchment. Research has been focussed on water use by different dryland vegetation, in particular commercial forestry which has been declared a Stream Flow Reduction Activity for which a water use license is required for production. Consequently, concerns about the water use of other dryland crops have lead to a need to quantify water use by other land uses, particularly sugarcane. In this document, previous research focussed on water use by sugarcane is reviewed and summarised, together with an experiment where an energy balance approach has been used to quantify water consumption in the form of total evaporation for an area of sugarcane production in the KwaZulu-Natal Midlands with an assessment of the seasonal variability of this water consumption for a period of 1 year. The study was performed using a Large Aperture Scintillometer to measure sensible heat flux, whilst all other energy balance components, as well as rainfall, soil moisture and other climatic data were obtained using standard methods. Total evaporation was estimated from latent heat flux which was derived as a residual of the energy balance. Total evaporation varies over the year with substantially higher values occurring in summer in response to high energy and water availability. Over the year, the crop used approximately 630mm of water which equates to 53% of rainfall at the site. The two main factors affecting the seasonal variability of water use by sugarcane are net radiation and soil moisture content. In the wetter months when soil moisture is readily available, net radiation limits total evaporation. In the drier months, soil moisture is not as readily available, and limits total evaporation. Air temperature and relative humidity proved to also be important considerations in their effect on total evaporation. The total evaporation estimates obtained could be compared to a baseline (grassland) and used in simulations for a better understanding of the stream flow reduction potential of sugarcane and the seasonal variability thereof. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.
24

Farmers’ awareness of climate change and variability and it’s effects on agricultural productivity: (the case of King Sabata Dalindyebo Municipalty in Eastern Cape)

Mdoda, Lelethu January 2014 (has links)
Climate is an important factor of agricultural productivity and many rural dwellers in developing countries depend on agriculture and are highly affected by climate change and variability. The world is currently experiencing climatic changes and variability conditions which results in high temperatures, low rainfall patterns, shortage of water and drought persistence. Climate change and variability is affecting weather patterns and shifting seasons which results in serious repercussions on smallholder farmers. Smallholder farmers are extremely vulnerable to climate change and variability because their farming and production systems are climate sensitive and are not rebound to climate stresses. These adverse effects in developing countries arise from different climate change and variability-related causes, notable extreme weather events, food security, increased health risks in agriculture from vector home diseases, and temperature-related morbidity in environments. The study was carried in King Sabata Dalindyebo Municipality in the Eastern Cape Province in South Africa. This study examines farmers’ awareness of climate change and variability and its effects on agricultural productivity in King Sabata Dalindyebo municipality using a Descriptive Statistics, Binary and Ricardian Model fitted to data from a cross-sectional survey of 200 farmers in King Sabata Dalindyebo Municipality. Both primary and secondary data was used. This research study estimates the effects of climate change and variability on King Sabata Dalindyebo agricultural productivity using a continental dimension of Ricardian analysis. Results revealed that local farmers were aware of climate change and variability and perceived changes in average temperatures and rainfall. The changes in average temperatures and rainfall had adverse effects on crop and livestock production. However, farmers’ awareness of climate change is not to an extent that they presume adaptation to climate change as a necessity and crucial. The results show that climate change and variability affects farm income and there is a non-linear relationship existing between climatic variables (temperature and precipitation) and farm income which depicts U-shaped. The study results indicated that climate change and variability affect agricultural productivity and have an effect on agricultural productivity in King Sabata Dalindyebo Municipality. In view of the research findings, several policy proposals are suggested. The study findings suggest that climate change and variability must be taken seriously and monitored. Policy makers and government officials must support farmers with information distribution,education, market access, well trained extension agents, credit and information about mitigation strategies to climate change and variability which includes institutional and technological methods, particularly smallholder farmers.
25

Impact of irrigation with gypsiferous mine water on the water resources of parts of the upper Olifants basin.

Idowu, Olufemi Abiola. January 2007 (has links)
The generation of large quantities of mine wastewater in South African coal mines and the needs for a cost effective, as well as an environmentally sustainable manner of mine water disposal, have fostered interests in the possibility of utilizing mine water for irrigation. Such a possibility will not only provide a cost-effective method of minimizing excess mine drainage, as treatment using physical, chemical and biological methods can be prohibitively expensive, but will also stabilize the dry-land crop production by enhancing dry season farming. Considering the arid to semi-arid climate of South Africa, the utilization of mine water for irrigation will also boost the beneficial exploitation of the available water resources and relieve the increasing pressure on, and the competition for, dwindling amounts of good quality water by the various sectors of the economy. The disposal of excess gypsiferous mine water through irrigation has been researched in a few collieries in the Witbank area. In this study, the assessment of the impacts of using gypsiferous mine water for irrigation were carried out in parts of the Upper Olifants basin upstream of Witbank Dam, using the ACRU2000 model and its salinity module known as ACRUSalinity. The study area was chosen on the bases of locations of previous field trials and the availability of mine water for large-scale irrigation. The primary objectives of the study were the development of relevant modules in ACRU2000 and ACRUSalinity to enable appropriate modelling and assessment of the impact of large-scale irrigation with mine water and the application of the modified models to the chosen study area. The methodology of the study included the modifications of ACRU2000 and ACRUSalinity and their application at three scales of study, viz. centre pivot, catchment and mine scales. The soils, hydrologic and salt distribution response units obtained from the centre pivot scale study were employed as inputs into the catchment scale study. The soils, hydrologic and salt distribution response units obtained from the catchment assessment were in turn applied in similar land segments identified in the mine used for the mine scale study. The modifications carried out included the incorporation of underground reservoirs as representations of underground mine-out areas, multiple water and associated salt load transfers into and out of a surface reservoir, seepages from groundwater into opencast pits, precipitation of salts in irrigated and non-irrigated areas and the incorporation of a soil surface layer into ACRUSalinity to account for the dissolution of salts during rainfall events. Two sites were chosen for the centre pivot scale study. The two sites (Syferfontein pivot of 21 ha, located in Syferfontein Colliery on virgin soils; Tweefontein pivot of 20 ha, located in Kleinkopje Colliery on rehabilitated soils) were equipped with centre pivots (which irrigated agricultural crops with mine water), as well as with rainfall, irrigation water and soil water monitoring equipment. The pivots were contoured and waterways constructed so that the runoff could leave the pivots over a weir (at Tweefontein pivot) or flume (at Syferfontein pivot) where the automatic monitoring of the quantity and quality of runoff were carried out. The runoff quantities and qualities from the pivots were used for verification of the modified ACRU2000 and ACRUSalinity. The catchment scale study was on the Tweefontein Pan catchment, which was a virgin area mainly within the Kleinkopje Colliery, draining into the Tweefontein Pan. The data on the water storage and qualities in Tweefontein Pan, as well as the soil water salinities in the irrigated area located within the catchment were used for verification of results. In the catchment scale study, different scenarios, including widespread irrigation on virgin and rehabilitated soils, were simulated and evaluated. For the mine scale study, the Kleinkopje Colliery was used. The colliery was delineated into 29 land segment areas and categorized into seven land use types, on the basis of the vegetation and land uses identified in different parts of colliery. The centre pivot and catchment scale studies indicated that the impacts of irrigation with low quality mine water on the water resources are dependent on the soil types, climate, the characteristics and the amount of the irrigation mine water applied, whether irrigation was on virgin on rehabilitated soils and the status of the mine in terms of whether a regional water table has been re-established in an opencast mining system or not. The studies further indicated that the irrigation of agricultural crops with low quality mine water may lead to increases in soil water salinity and drainage to groundwater, but that the mine water use for irrigation iii purposes can be successfully carried out as most of the water input onto the irrigated area will be lost through total evaporation and a significant proportion of the salt input, both from rainfall and irrigation water, will either be precipitated in the soil horizons or dissolved in the soil water of the soil horizons. By irrigating with a saline mine water therefore, the salts associated with the low quality mine water can be removed from the water system, thereby reducing the possibility of off-site salt export and environmental pollution. On-site salt precipitation, however, may lead to accumulation of salts in the soil horizons and consequent restriction of crop yields. Therefore, efficient cropping practices, such as leaching and selection of tolerant crops to the expected soil salinity, may be required in order to avoid the impact of long-term salinity build up and loss of crop yields. The simulated mean annual runoff and salt load contribution to Witbank Dam from the Kleinkopje Colliery were 2.0 x 103 MI and 392 tons respectively. The mean annual runoff and salt load represented 2.7% and 1.4% of the average water and salt load storage in Witbank Dam respectively. About 45% of the total water inflow and 65% of the total salt load contribution from the study area into Witbank Dam resulted from groundwater storage. From the scenario simulations, the least salt export would occur when widespread irrigation is carried out in rehabilitated areas prior to the re-establishment of the water table due to a lower runoff and runoff salt load. It may therefore be a better water management strategy in active collieries if irrigation with mine water is carried out on rehabilitated soils. In conclusion, this research work has shown that successful irrigation of some (salt tolerance) crops with low quality mine water can be done, although increases in the soil water salinity of the irrigated area, runoff from the irrigated area and drainage to the groundwater store can occur. Through the modifications carried out in the ACRU2000 model and the ACRUSalinity module in this research work, a tool has been developed, not only for application in the integrated assessment of impact of irrigation with mine water on water resources, but also for the integrated assessment and management of water resources in coal-mining environments in South Africa. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

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