Effects of removing Acacia Mearnsii on the water table, soil and vegetation properties in the Tsomo Valley of the Eastern Cape Province, South Africa
- Moyo, Hloniphani Peter Mthunzi
- Authors: Moyo, Hloniphani Peter Mthunzi
- Date: 2010
- Subjects: Plant-water relationships , Acacia mearnsii , Water table , Wattles (Plants) -- South Africa -- Eastern Cape , Streamflow -- South Africa -- Eastern Cape , Groundwater -- South Africa -- Eastern Cape , Groundwater recharge -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Pasture Science)
- Identifier: vital:11173 , http://hdl.handle.net/10353/d1001011 , Plant-water relationships , Acacia mearnsii , Water table , Wattles (Plants) -- South Africa -- Eastern Cape , Streamflow -- South Africa -- Eastern Cape , Groundwater -- South Africa -- Eastern Cape , Groundwater recharge -- South Africa -- Eastern Cape
- Full Text:
- Date Issued: 2010
- Authors: Moyo, Hloniphani Peter Mthunzi
- Date: 2010
- Subjects: Plant-water relationships , Acacia mearnsii , Water table , Wattles (Plants) -- South Africa -- Eastern Cape , Streamflow -- South Africa -- Eastern Cape , Groundwater -- South Africa -- Eastern Cape , Groundwater recharge -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Pasture Science)
- Identifier: vital:11173 , http://hdl.handle.net/10353/d1001011 , Plant-water relationships , Acacia mearnsii , Water table , Wattles (Plants) -- South Africa -- Eastern Cape , Streamflow -- South Africa -- Eastern Cape , Groundwater -- South Africa -- Eastern Cape , Groundwater recharge -- South Africa -- Eastern Cape
- Full Text:
- Date Issued: 2010
Effects of salinity on the growth and lipid production of ten species of microalgae from the Swartkops saltworks : a biodiesel perspective
- Authors: Sonnekus, Martinus Jakobus
- Date: 2010
- Subjects: Microalgae -- South Africa -- Swartkops , Salinity -- South Africa -- Swartkops , Biodiesel fuels
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10618 , http://hdl.handle.net/10948/1097 , Microalgae -- South Africa -- Swartkops , Salinity -- South Africa -- Swartkops , Biodiesel fuels
- Description: Biodiesel from microalgae is a viable alternative for replacing the global demand for petro-diesel. High biomass and lipid production are key desirable characteristics needed in a species to be used for biodiesel production. It has been demonstrated in literature that the increase in salinity can increase the lipid content of microalgae, but lower the growth rate of a species. Therefore the effect that salinity has on the growth and lipid content of ten microalgal species, isolated from a warm temperate solar saltworks, was investigated. The microalgae were cultivated at a temperature of 22°C and at salinities ranging from 17 to 70 psu. It was found that growth and lipid production for all species were influenced to some degree by the salinity. Growth rates greater than 0.6 d-1 showed a decrease with higher salinity. Most (71 percent) of the growth rates that exceeded 0.6 per day were exhibited by cultures exposed to normal salinity (35 psu). This shift is a good indication that salinity inhibits/slows down growth and that the species in general prefer lower salinity conditions. Growth rates ranged from 0.17 ± 0.05 to 1.19 ± 0.17 d-1. Lipid content for the diatoms (2.78 ± 0.36 to 10.86 ± 4.59 percent DW) were lower than expected, whereas the lipid content for the green flagellates (3.10 ± 1.56 to 22.64 ± 1.19 percent DW) was on par with that reported in literature. To bring results into perspective a production model was developed to simulate a production scenario at the Swartkops Saltworks. Lipid and productivity results obtained in this study were used to estimate how much oil and biomass can be produced within the ponds of the Swartkops Saltworks. The model showed that although microalgae cultivation for biodiesel is technically feasible, at present it is not economically viable to do so.
- Full Text:
- Date Issued: 2010
- Authors: Sonnekus, Martinus Jakobus
- Date: 2010
- Subjects: Microalgae -- South Africa -- Swartkops , Salinity -- South Africa -- Swartkops , Biodiesel fuels
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10618 , http://hdl.handle.net/10948/1097 , Microalgae -- South Africa -- Swartkops , Salinity -- South Africa -- Swartkops , Biodiesel fuels
- Description: Biodiesel from microalgae is a viable alternative for replacing the global demand for petro-diesel. High biomass and lipid production are key desirable characteristics needed in a species to be used for biodiesel production. It has been demonstrated in literature that the increase in salinity can increase the lipid content of microalgae, but lower the growth rate of a species. Therefore the effect that salinity has on the growth and lipid content of ten microalgal species, isolated from a warm temperate solar saltworks, was investigated. The microalgae were cultivated at a temperature of 22°C and at salinities ranging from 17 to 70 psu. It was found that growth and lipid production for all species were influenced to some degree by the salinity. Growth rates greater than 0.6 d-1 showed a decrease with higher salinity. Most (71 percent) of the growth rates that exceeded 0.6 per day were exhibited by cultures exposed to normal salinity (35 psu). This shift is a good indication that salinity inhibits/slows down growth and that the species in general prefer lower salinity conditions. Growth rates ranged from 0.17 ± 0.05 to 1.19 ± 0.17 d-1. Lipid content for the diatoms (2.78 ± 0.36 to 10.86 ± 4.59 percent DW) were lower than expected, whereas the lipid content for the green flagellates (3.10 ± 1.56 to 22.64 ± 1.19 percent DW) was on par with that reported in literature. To bring results into perspective a production model was developed to simulate a production scenario at the Swartkops Saltworks. Lipid and productivity results obtained in this study were used to estimate how much oil and biomass can be produced within the ponds of the Swartkops Saltworks. The model showed that although microalgae cultivation for biodiesel is technically feasible, at present it is not economically viable to do so.
- Full Text:
- Date Issued: 2010
Effects of treatment on Lantana camara (L.) and the restoration potential of riparian seed banks in cleared areas of the Victoria Falls World Heritage Site, Livingstone, Zambia
- Nang'alelwa, Michael Mubitelela
- Authors: Nang'alelwa, Michael Mubitelela
- Date: 2010
- Subjects: Lantana camara -- Victoria Falls (Zambia and Zimbabwe) , Lantana camara -- Biological control -- Victoria Falls (Zambia and Zimbabwe) , Invasive plants -- Biological control -- Victoria Falls (Zambia and Zimbabwe) , Riparian restoration -- Victoria Falls (Zambia and Zimbabwe) , Riparian ecology -- Victoria Falls (Zambia and Zimbabwe)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4217 , http://hdl.handle.net/10962/d1003786 , Lantana camara -- Victoria Falls (Zambia and Zimbabwe) , Lantana camara -- Biological control -- Victoria Falls (Zambia and Zimbabwe) , Invasive plants -- Biological control -- Victoria Falls (Zambia and Zimbabwe) , Riparian restoration -- Victoria Falls (Zambia and Zimbabwe) , Riparian ecology -- Victoria Falls (Zambia and Zimbabwe)
- Description: The exotic plant Lantana camara L. has invaded the riparian areas of the Victoria Falls World Heritage Site in Livingstone, southern Zambia, threatening native plant communities which support populations of species of special concern. I trialled the mechanical control method of manual uprooting and 3 different herbicides applied through paint brushing of an imazapyr concentrate at 250g. l¯¹, spraying on cut stumps with metsulfron methyl at 600g.l¯¹, and foliar spraying on re-emergent lantana foliage with glyphosate at a dosage of 166g. l¯¹ in July 2008 in 20 100m2 treatment plots, 5 invaded control plots and 5 uninvaded controls. Follow-up treatments for re-sprouting lantana stumps and emerging seedlings were undertaken in June 2009. I measured effectiveness of the methods using adult lantana mortality in June 2009 and lantana seedling density in the different treatment plots during the follow-up exercise. The cost of the various methods and human labour applied were compared across the four treatments at initial clear and at follow-up. All treatments recorded a high adult lantana mortality rate, though there were no significant differences in lantana adult mortality amongst the treatments. Overall, uprooting had the highest adult mortality, followed by imazapyr, metsulfron and lastly glyphosate. Germination of lantana seedlings after clearing was high for all treatments but with no significant differences occurring between the treatments. Both adult lantana mortality and seedling density were however significantly different from the control. With labour included, chemical costs were far higher relative to uprooting, though uprooting costs were the highest when it came to the follow-up because of the emerging seedlings and some resprouting stumps. The effects of mechanical and chemical treatments on vegetation composition in the cleared areas were also assessed in order to detect any non-target and medium term effects of treatments. Contrary to expectation, none of the chemicals showed any significant effects on vegetation composition in the short and medium-term and no significant differences were found in plant species richness, diversity and seedling density between invaded and uninvaded plots at baseline, in October 2008 and in September 2009. In order to determine potential for unaided vegetation recovery in the riparian areas of the study site after lantana clearing, I conducted an investigation of soil seed banks and seed rain using 60 seed bank samples measuring 1800m³ collected from 30 invaded and uninvaded plots. Using the seedling emergence method, 1, 991 seedlings belonging to 66 species representing 27 families germinated from the seed bank. Sedges (Cyperaceae family) were the most abundant taxa in the seed banks from invaded areas, followed by Ageratum conyzoides, lantana, Triumfetta annua and Achyranthes aspera which also occurred in the uninvaded soil seed banks. The seed banks from uninvaded plots were dominated by the grass Oplismenus hirtellus. Overall, species richness, diversity and seedling density from seed banks in invaded areas did not differ significantly from seed bank in uninvaded areas and there was a low similarity in species composition when above ground vegetation was compared to seed banks from invaded and uninvaded areas. It would appear if natural regeneration occured from the current seed bank in disturbed areas, future vegetation would largely comprise of short lived, early successional species in the short term as the seed bank is dominated by non-native herbaceous weedy species. From the seed traps investigating seed rain, a total of 27 species numbering 623 individual seeds were found in the thirty 1m² seedtraps distributed in invaded and uninvaded areas at the five sites, over an intermittent period of three months. Lantana had the highest monthly arrival rate in the seed traps followed by Phoenix reclinata and Ricinus communis. The number of species with invasive potential found in the seed traps located in invaded areas was more than that found in seed traps under native vegetation cover by far. Considerable forest remnants still occur around the invaded sites, and these could serve as an important source for long-term natural re-establishment of native vegetation if seed availability by animals and wind dispersal continues, while the re-invasion of lantana is prevented by ongoing follow-ups and futher clearing of lantana invaded areas. It is concluded that while uprooting and other treatments are effective in the control of lantana, its successful control in the Victoria Falls World Heritage Site will require extensive clearing to keep it from reinvading infested areas after clearing as shown by the seed rain data. The high seedling density of lantana in the seed banks and in the cleared areas shows the need for ongoing follow-up in order to deplete soil stored seed banks. There is need for longer term research to establish what the exact follow-up requirements are in order to contain lantana re-infestation and create favourable micro-sites for native species to establish. It is predicted that ongoing lantana control in the cleared plots will most likely initiate long-term community recovery.
- Full Text:
- Date Issued: 2010
- Authors: Nang'alelwa, Michael Mubitelela
- Date: 2010
- Subjects: Lantana camara -- Victoria Falls (Zambia and Zimbabwe) , Lantana camara -- Biological control -- Victoria Falls (Zambia and Zimbabwe) , Invasive plants -- Biological control -- Victoria Falls (Zambia and Zimbabwe) , Riparian restoration -- Victoria Falls (Zambia and Zimbabwe) , Riparian ecology -- Victoria Falls (Zambia and Zimbabwe)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4217 , http://hdl.handle.net/10962/d1003786 , Lantana camara -- Victoria Falls (Zambia and Zimbabwe) , Lantana camara -- Biological control -- Victoria Falls (Zambia and Zimbabwe) , Invasive plants -- Biological control -- Victoria Falls (Zambia and Zimbabwe) , Riparian restoration -- Victoria Falls (Zambia and Zimbabwe) , Riparian ecology -- Victoria Falls (Zambia and Zimbabwe)
- Description: The exotic plant Lantana camara L. has invaded the riparian areas of the Victoria Falls World Heritage Site in Livingstone, southern Zambia, threatening native plant communities which support populations of species of special concern. I trialled the mechanical control method of manual uprooting and 3 different herbicides applied through paint brushing of an imazapyr concentrate at 250g. l¯¹, spraying on cut stumps with metsulfron methyl at 600g.l¯¹, and foliar spraying on re-emergent lantana foliage with glyphosate at a dosage of 166g. l¯¹ in July 2008 in 20 100m2 treatment plots, 5 invaded control plots and 5 uninvaded controls. Follow-up treatments for re-sprouting lantana stumps and emerging seedlings were undertaken in June 2009. I measured effectiveness of the methods using adult lantana mortality in June 2009 and lantana seedling density in the different treatment plots during the follow-up exercise. The cost of the various methods and human labour applied were compared across the four treatments at initial clear and at follow-up. All treatments recorded a high adult lantana mortality rate, though there were no significant differences in lantana adult mortality amongst the treatments. Overall, uprooting had the highest adult mortality, followed by imazapyr, metsulfron and lastly glyphosate. Germination of lantana seedlings after clearing was high for all treatments but with no significant differences occurring between the treatments. Both adult lantana mortality and seedling density were however significantly different from the control. With labour included, chemical costs were far higher relative to uprooting, though uprooting costs were the highest when it came to the follow-up because of the emerging seedlings and some resprouting stumps. The effects of mechanical and chemical treatments on vegetation composition in the cleared areas were also assessed in order to detect any non-target and medium term effects of treatments. Contrary to expectation, none of the chemicals showed any significant effects on vegetation composition in the short and medium-term and no significant differences were found in plant species richness, diversity and seedling density between invaded and uninvaded plots at baseline, in October 2008 and in September 2009. In order to determine potential for unaided vegetation recovery in the riparian areas of the study site after lantana clearing, I conducted an investigation of soil seed banks and seed rain using 60 seed bank samples measuring 1800m³ collected from 30 invaded and uninvaded plots. Using the seedling emergence method, 1, 991 seedlings belonging to 66 species representing 27 families germinated from the seed bank. Sedges (Cyperaceae family) were the most abundant taxa in the seed banks from invaded areas, followed by Ageratum conyzoides, lantana, Triumfetta annua and Achyranthes aspera which also occurred in the uninvaded soil seed banks. The seed banks from uninvaded plots were dominated by the grass Oplismenus hirtellus. Overall, species richness, diversity and seedling density from seed banks in invaded areas did not differ significantly from seed bank in uninvaded areas and there was a low similarity in species composition when above ground vegetation was compared to seed banks from invaded and uninvaded areas. It would appear if natural regeneration occured from the current seed bank in disturbed areas, future vegetation would largely comprise of short lived, early successional species in the short term as the seed bank is dominated by non-native herbaceous weedy species. From the seed traps investigating seed rain, a total of 27 species numbering 623 individual seeds were found in the thirty 1m² seedtraps distributed in invaded and uninvaded areas at the five sites, over an intermittent period of three months. Lantana had the highest monthly arrival rate in the seed traps followed by Phoenix reclinata and Ricinus communis. The number of species with invasive potential found in the seed traps located in invaded areas was more than that found in seed traps under native vegetation cover by far. Considerable forest remnants still occur around the invaded sites, and these could serve as an important source for long-term natural re-establishment of native vegetation if seed availability by animals and wind dispersal continues, while the re-invasion of lantana is prevented by ongoing follow-ups and futher clearing of lantana invaded areas. It is concluded that while uprooting and other treatments are effective in the control of lantana, its successful control in the Victoria Falls World Heritage Site will require extensive clearing to keep it from reinvading infested areas after clearing as shown by the seed rain data. The high seedling density of lantana in the seed banks and in the cleared areas shows the need for ongoing follow-up in order to deplete soil stored seed banks. There is need for longer term research to establish what the exact follow-up requirements are in order to contain lantana re-infestation and create favourable micro-sites for native species to establish. It is predicted that ongoing lantana control in the cleared plots will most likely initiate long-term community recovery.
- Full Text:
- Date Issued: 2010
Efficient rectenna circuits for microwave wireless power transmission
- Authors: Teru, Agboola Awolola
- Date: 2010
- Subjects: Electric power production -- Technological innovations , Integrated circuits -- Design and construction , Electronic circuit design , Semiconductors -- Design and construction
- Language: English
- Type: Thesis , Masters , MSc (Physics)
- Identifier: vital:11590 , http://hdl.handle.net/10353/481 , Electric power production -- Technological innovations , Integrated circuits -- Design and construction , Electronic circuit design , Semiconductors -- Design and construction
- Description: Miniaturisation has been the holy grail of mobile technology. The ability to move around with our gadgets, especially the ones for communication and entertainment, has been what semiconductor scientists have battled over the past decades. Miniaturisation brings about reduced consumption in power and ease of mobility. However, the main impediment to untethered mobility of our gadgets has been the lack of unlimited power supply. The battery had filled this gap for some time, but due to the increased functionalities of these mobile gadgets, increasing the battery capacity would increase the weight of the device considerably that it would eventually become too heavy to carry around. Moreover, the fact that these batteries need to be recharged means we are still not completely free of power cords. The advent of low powered micro-controllers and sensors has created a huge industry for more powerful devices that consume a lot less power. These devices have encouraged hardware designers to reduce the power consumption of the gadgets. This has encouraged the idea of wireless power transmission on another level. With lots of radio frequency energy all around us, from our cordless phones to the numerous mobile cell sites there has not been a better time to delve more into research on WPT. This study looks at the feasibilities of WPT in small device applications where very low power is consumed to carry out some important functionality. The work done here compared two rectifying circuits’ efficiencies and ways to improve on the overall efficiencies. The results obtained show that the full wave rectifier would be the better option when designing a WPT system as more power can be drawn from the rectenna. The load also had a great role as this determined the amount of power drawn from the circuitry.
- Full Text:
- Date Issued: 2010
- Authors: Teru, Agboola Awolola
- Date: 2010
- Subjects: Electric power production -- Technological innovations , Integrated circuits -- Design and construction , Electronic circuit design , Semiconductors -- Design and construction
- Language: English
- Type: Thesis , Masters , MSc (Physics)
- Identifier: vital:11590 , http://hdl.handle.net/10353/481 , Electric power production -- Technological innovations , Integrated circuits -- Design and construction , Electronic circuit design , Semiconductors -- Design and construction
- Description: Miniaturisation has been the holy grail of mobile technology. The ability to move around with our gadgets, especially the ones for communication and entertainment, has been what semiconductor scientists have battled over the past decades. Miniaturisation brings about reduced consumption in power and ease of mobility. However, the main impediment to untethered mobility of our gadgets has been the lack of unlimited power supply. The battery had filled this gap for some time, but due to the increased functionalities of these mobile gadgets, increasing the battery capacity would increase the weight of the device considerably that it would eventually become too heavy to carry around. Moreover, the fact that these batteries need to be recharged means we are still not completely free of power cords. The advent of low powered micro-controllers and sensors has created a huge industry for more powerful devices that consume a lot less power. These devices have encouraged hardware designers to reduce the power consumption of the gadgets. This has encouraged the idea of wireless power transmission on another level. With lots of radio frequency energy all around us, from our cordless phones to the numerous mobile cell sites there has not been a better time to delve more into research on WPT. This study looks at the feasibilities of WPT in small device applications where very low power is consumed to carry out some important functionality. The work done here compared two rectifying circuits’ efficiencies and ways to improve on the overall efficiencies. The results obtained show that the full wave rectifier would be the better option when designing a WPT system as more power can be drawn from the rectenna. The load also had a great role as this determined the amount of power drawn from the circuitry.
- Full Text:
- Date Issued: 2010
Electrocatalytic oxidation of amitrole and diuron on iron (II) tetraaminophthalocyanine-single walled carbon nanotube dendrimer
- Mugadza, Tawanda, Nyokong, Tebello
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/262611 , vital:53536 , xlink:href="https://doi.org/10.1016/j.electacta.2009.12.051"
- Description: FeTAPc-single walled carbon nanotube (SWCNT) dendrimers are employed as glassy carbon electrode modifiers for the electrocatalytic oxidations of amitrole and diuron. The catalytic rate constants were 4.55 × 103 M−1 s−1 and 1.79 × 104 M−1 s−1 for amitrole and diuron, respectively using chronoamperometric studies. The diffusion constants were found to be 1.52 × 10−4 cm2 s−1 and 1.91 × 10−4 cm2 s−1 for diuron and amitrole, respectively. The linear concentration range for both were from 5.0 × 10−5 to 1.0 × 10−4 M and sensitivities of 0.6603 μA/μM and 0.6641 μA/μM for amitrole and diuron, with corresponding limits of detection of 2.15 × 10−7 and 2.6 × 10−7 M using the 3δ notation, respectively.
- Full Text:
- Date Issued: 2010
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/262611 , vital:53536 , xlink:href="https://doi.org/10.1016/j.electacta.2009.12.051"
- Description: FeTAPc-single walled carbon nanotube (SWCNT) dendrimers are employed as glassy carbon electrode modifiers for the electrocatalytic oxidations of amitrole and diuron. The catalytic rate constants were 4.55 × 103 M−1 s−1 and 1.79 × 104 M−1 s−1 for amitrole and diuron, respectively using chronoamperometric studies. The diffusion constants were found to be 1.52 × 10−4 cm2 s−1 and 1.91 × 10−4 cm2 s−1 for diuron and amitrole, respectively. The linear concentration range for both were from 5.0 × 10−5 to 1.0 × 10−4 M and sensitivities of 0.6603 μA/μM and 0.6641 μA/μM for amitrole and diuron, with corresponding limits of detection of 2.15 × 10−7 and 2.6 × 10−7 M using the 3δ notation, respectively.
- Full Text:
- Date Issued: 2010
Electrochemical, spectroscopic and microscopic studies of new manganese phthalocyanine complexes in solution and as self-assembled monolayers on gold
- Coates, Megan, Antunes, Edith M, Nyokong, Tebello
- Authors: Coates, Megan , Antunes, Edith M , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261144 , vital:53363 , xlink:href="https://doi.org/10.1142/S1088424610002471"
- Description: Four new manganese(III) phthalocyanines (3a–d), octasubstituted at the peripheral position with pentylthio, decylthio, benzylthio, and phenylthio groups, respectively, were synthesized. Their specific electrochemical, spectroscopic and microscopic properties in solution and as self-assembled monolayers on gold were characterized. The UV-vis spectra confirmed red-shifted Q bands for all the complexes, due to the effect of the central metal and the electron-donating substituents. Three redox couples were visible during cyclic voltammetry studies for the four complexes, and spectroelectrochemistry confirmed the couples as corresponding to MnIIIPc-2/MnIIPc-2 (II) (metal reduction), MnIIPc-2/MnIIPc-3 (III) (ring reduction) and MnIIIPc-1/MnIIIPc-2 (I) (ring oxidation). Electrochemistry was also used to determine the blocking characteristics of the MnPc self-assembled monolayers on gold, which proved to be highly dependent on the type of substituent. Other methods of characterization included Raman spectroscopy, atomic force and scanning electrochemical microscopy analyses of the SAMs.
- Full Text:
- Date Issued: 2010
- Authors: Coates, Megan , Antunes, Edith M , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261144 , vital:53363 , xlink:href="https://doi.org/10.1142/S1088424610002471"
- Description: Four new manganese(III) phthalocyanines (3a–d), octasubstituted at the peripheral position with pentylthio, decylthio, benzylthio, and phenylthio groups, respectively, were synthesized. Their specific electrochemical, spectroscopic and microscopic properties in solution and as self-assembled monolayers on gold were characterized. The UV-vis spectra confirmed red-shifted Q bands for all the complexes, due to the effect of the central metal and the electron-donating substituents. Three redox couples were visible during cyclic voltammetry studies for the four complexes, and spectroelectrochemistry confirmed the couples as corresponding to MnIIIPc-2/MnIIPc-2 (II) (metal reduction), MnIIPc-2/MnIIPc-3 (III) (ring reduction) and MnIIIPc-1/MnIIIPc-2 (I) (ring oxidation). Electrochemistry was also used to determine the blocking characteristics of the MnPc self-assembled monolayers on gold, which proved to be highly dependent on the type of substituent. Other methods of characterization included Raman spectroscopy, atomic force and scanning electrochemical microscopy analyses of the SAMs.
- Full Text:
- Date Issued: 2010
Emotional intelligence and locus of control of adult breast cancer patients receiving treatment
- Authors: Swartz, Esti
- Date: 2010
- Subjects: Breast -- Cancer -- Patients -- Psychological aspects , Breast -- Cancer -- Patients
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9949 , http://hdl.handle.net/10948/d1015686
- Description: Breast cancer is the most prevalent cancer of women in South Africa, with one in twenty-seven women diagnosed with breast cancer in their lifetime. By building on human strengths, ways can be found to cope effectively with adversity. This will contribute to psychological well-being and result in living constructive and meaningful lives. Emotional intelligence and locus of control are two constructs which, according to previous research, may be associated with psychological wellbeing. Limited research has been conducted on these constructs in populations facing adversity. Adaptation to breast cancer treatment is considered to be an extremely difficult process. The research aimed to explore and describe emotional intelligence and locus of control within an adult breast cancer population. A sample of 67 breast cancer patients receiving treatment was approached to complete a biographical questionnaire and two pencil-and-paper questionnaires. Descriptive and inferential statistics were be used to analyze the data. The results of the quantitative analysis indicated a significant negative correlation between emotional intelligence and locus of control which shows that patients with higher levels of emotional intelligence possess more internal locus of control orientations, while patients with lower emotional intelligence possess more external locus of control orientations. The population presented with above average emotional intelligence and an internal locus of control orientation. The study can be regarded as the first step in opening a field of research which could contribute to more effective coping and the overall psychological well-being of individuals facing adversity in South Africa. Furthermore, the findings of the study contributed to understanding the role of emotional intelligence and locus of control in these populations and encouraged further research and the development and implementation of programmes that promote skills development in these areas.
- Full Text:
- Date Issued: 2010
- Authors: Swartz, Esti
- Date: 2010
- Subjects: Breast -- Cancer -- Patients -- Psychological aspects , Breast -- Cancer -- Patients
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9949 , http://hdl.handle.net/10948/d1015686
- Description: Breast cancer is the most prevalent cancer of women in South Africa, with one in twenty-seven women diagnosed with breast cancer in their lifetime. By building on human strengths, ways can be found to cope effectively with adversity. This will contribute to psychological well-being and result in living constructive and meaningful lives. Emotional intelligence and locus of control are two constructs which, according to previous research, may be associated with psychological wellbeing. Limited research has been conducted on these constructs in populations facing adversity. Adaptation to breast cancer treatment is considered to be an extremely difficult process. The research aimed to explore and describe emotional intelligence and locus of control within an adult breast cancer population. A sample of 67 breast cancer patients receiving treatment was approached to complete a biographical questionnaire and two pencil-and-paper questionnaires. Descriptive and inferential statistics were be used to analyze the data. The results of the quantitative analysis indicated a significant negative correlation between emotional intelligence and locus of control which shows that patients with higher levels of emotional intelligence possess more internal locus of control orientations, while patients with lower emotional intelligence possess more external locus of control orientations. The population presented with above average emotional intelligence and an internal locus of control orientation. The study can be regarded as the first step in opening a field of research which could contribute to more effective coping and the overall psychological well-being of individuals facing adversity in South Africa. Furthermore, the findings of the study contributed to understanding the role of emotional intelligence and locus of control in these populations and encouraged further research and the development and implementation of programmes that promote skills development in these areas.
- Full Text:
- Date Issued: 2010
Empirically modelled Pc3 activity based on solar wind parameters
- Heilig, B, Lotz, Stefanus I, Verő, J, Sutcliffe, P, Reda, J, Pajunpää, G, Raita, T
- Authors: Heilig, B , Lotz, Stefanus I , Verő, J , Sutcliffe, P , Reda, J , Pajunpää, G , Raita, T
- Date: 2010
- Language: English
- Type: text , Article
- Identifier: vital:6814 , http://hdl.handle.net/10962/d1004324
- Description: It is known that under certain solar wind (SW)/interplanetary magnetic field (IMF) conditions (e.g. high SW speed, low cone angle) the occurrence of ground-level Pc3–4 pulsations is more likely. In this paper we demonstrate that in the event of anomalously low SW particle density, Pc3 activity is extremely low regardless of otherwise favourable SW speed and cone angle. We re-investigate the SW control of Pc3 pulsation activity through a statistical analysis and two empirical models with emphasis on the influence of SW density on Pc3 activity. We utilise SW and IMF measurements from the OMNI project and ground-based magnetometer measurements from the MM100 array to relate SW and IMF measurements to the occurrence of Pc3 activity. Multiple linear regression and artificial neural network models are used in iterative processes in order to identify sets of SW-based input parameters, which optimally reproduce a set of Pc3 activity data. The inclusion of SW density in the parameter set significantly improves the models. Not only the density itself, but other density related parameters, such as the dynamic pressure of the SW, or the standoff distance of the magnetopause work equally well in the model. The disappearance of Pc3s during low-density events can have at least four reasons according to the existing upstream wave theory: 1. Pausing the ion-cyclotron resonance that generates the upstream ultra low frequency waves in the absence of protons, 2. Weakening of the bow shock that implies less efficient reflection, 3. The SW becomes sub-Alfvénic and hence it is not able to sweep back the waves propagating upstream with the Alfvén-speed, and 4. The increase of the standoff distance of the magnetopause (and of the bow shock). Although the models cannot account for the lack of Pc3s during intervals when the SW density is extremely low, the resulting sets of optimal model inputs support the generation of mid latitude Pc3 activity predominantly through upstream waves.
- Full Text:
- Date Issued: 2010
- Authors: Heilig, B , Lotz, Stefanus I , Verő, J , Sutcliffe, P , Reda, J , Pajunpää, G , Raita, T
- Date: 2010
- Language: English
- Type: text , Article
- Identifier: vital:6814 , http://hdl.handle.net/10962/d1004324
- Description: It is known that under certain solar wind (SW)/interplanetary magnetic field (IMF) conditions (e.g. high SW speed, low cone angle) the occurrence of ground-level Pc3–4 pulsations is more likely. In this paper we demonstrate that in the event of anomalously low SW particle density, Pc3 activity is extremely low regardless of otherwise favourable SW speed and cone angle. We re-investigate the SW control of Pc3 pulsation activity through a statistical analysis and two empirical models with emphasis on the influence of SW density on Pc3 activity. We utilise SW and IMF measurements from the OMNI project and ground-based magnetometer measurements from the MM100 array to relate SW and IMF measurements to the occurrence of Pc3 activity. Multiple linear regression and artificial neural network models are used in iterative processes in order to identify sets of SW-based input parameters, which optimally reproduce a set of Pc3 activity data. The inclusion of SW density in the parameter set significantly improves the models. Not only the density itself, but other density related parameters, such as the dynamic pressure of the SW, or the standoff distance of the magnetopause work equally well in the model. The disappearance of Pc3s during low-density events can have at least four reasons according to the existing upstream wave theory: 1. Pausing the ion-cyclotron resonance that generates the upstream ultra low frequency waves in the absence of protons, 2. Weakening of the bow shock that implies less efficient reflection, 3. The SW becomes sub-Alfvénic and hence it is not able to sweep back the waves propagating upstream with the Alfvén-speed, and 4. The increase of the standoff distance of the magnetopause (and of the bow shock). Although the models cannot account for the lack of Pc3s during intervals when the SW density is extremely low, the resulting sets of optimal model inputs support the generation of mid latitude Pc3 activity predominantly through upstream waves.
- Full Text:
- Date Issued: 2010
Enhancing self-esteem as a teacher of English using action research
- Authors: Didloft, Virginia Charmaine
- Date: 2010
- Subjects: Self-esteem in children -- South Africa , Self-esteem -- Study and teaching , Self-perception in children -- South Africa , Social interaction in children -- South Africa , Educational psychology -- South Africa
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9496 , http://hdl.handle.net/10948/1520 , Self-esteem in children -- South Africa , Self-esteem -- Study and teaching , Self-perception in children -- South Africa , Social interaction in children -- South Africa , Educational psychology -- South Africa
- Description: This thesis offers a critical reflection of a study I initiated to enhance self-esteem for self-actualization. The research process involved enhancing my own self-esteem before facilitating the enhancement of the self-esteem of my participants. This endeavour included the simultaneous exposure given to researcher and researched, with the aim of helping to attain the respective transformative potentials of the latter. An action research methodology was used, intending to improve my own practice and to involve and learn from the participants in order for all relevant stakeholders to capitalize from the learning experience. Whilst undertaking this study, I learned to reflect on my values, attitudes and relationships with my learners. I also became aware of how individuals‟ perceptions of themselves can influence other aspects of their development. This awareness enabled me to become more sensitive to the emotional needs of the learners in my care and also led to a greater understanding of their individuality. I came to comprehend the impact of a positive self-esteem on the learning process that aided me in developing an understanding of the positive impact an enhanced self-esteem has on how my learners view themselves. In the course of the research, I developed an awareness of the need to create a caring practice centred on values of gentleness, respect, kindness, awareness and recognition of individual strengths. These afore-mentioned values are premised on the recognition and acknowledgement of basic human rights, inclusivity, equality and social justice; principles reflecting my own living standards. This heightened vii awareness influenced the ways I organized the learning and teaching process in my classroom. Enhancing my own self-esteem and those of my learners basically involved interchangeable interventions such as encouraging involvement, allocating responsibilities, creating opportunities for assertiveness and being generous with affirmation, praise and motivation. These endeavours occurred within a social constructivist approach, enabling participants to construct their own epistemologies within their respective ontologies. My findings offer new conceptualizations about how an enhanced self-esteem can help individuals realize their fullest potential.
- Full Text:
- Date Issued: 2010
- Authors: Didloft, Virginia Charmaine
- Date: 2010
- Subjects: Self-esteem in children -- South Africa , Self-esteem -- Study and teaching , Self-perception in children -- South Africa , Social interaction in children -- South Africa , Educational psychology -- South Africa
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9496 , http://hdl.handle.net/10948/1520 , Self-esteem in children -- South Africa , Self-esteem -- Study and teaching , Self-perception in children -- South Africa , Social interaction in children -- South Africa , Educational psychology -- South Africa
- Description: This thesis offers a critical reflection of a study I initiated to enhance self-esteem for self-actualization. The research process involved enhancing my own self-esteem before facilitating the enhancement of the self-esteem of my participants. This endeavour included the simultaneous exposure given to researcher and researched, with the aim of helping to attain the respective transformative potentials of the latter. An action research methodology was used, intending to improve my own practice and to involve and learn from the participants in order for all relevant stakeholders to capitalize from the learning experience. Whilst undertaking this study, I learned to reflect on my values, attitudes and relationships with my learners. I also became aware of how individuals‟ perceptions of themselves can influence other aspects of their development. This awareness enabled me to become more sensitive to the emotional needs of the learners in my care and also led to a greater understanding of their individuality. I came to comprehend the impact of a positive self-esteem on the learning process that aided me in developing an understanding of the positive impact an enhanced self-esteem has on how my learners view themselves. In the course of the research, I developed an awareness of the need to create a caring practice centred on values of gentleness, respect, kindness, awareness and recognition of individual strengths. These afore-mentioned values are premised on the recognition and acknowledgement of basic human rights, inclusivity, equality and social justice; principles reflecting my own living standards. This heightened vii awareness influenced the ways I organized the learning and teaching process in my classroom. Enhancing my own self-esteem and those of my learners basically involved interchangeable interventions such as encouraging involvement, allocating responsibilities, creating opportunities for assertiveness and being generous with affirmation, praise and motivation. These endeavours occurred within a social constructivist approach, enabling participants to construct their own epistemologies within their respective ontologies. My findings offer new conceptualizations about how an enhanced self-esteem can help individuals realize their fullest potential.
- Full Text:
- Date Issued: 2010
Enhancing the saccharolytic phase of sugar beet pulp via hemicellulase synergy
- Authors: Dredge, Roselyn Ann
- Date: 2010
- Subjects: Sugar plantations , Sugar plantations -- South Africa , Sugar beet industry -- South Africa , Saccharomyces cerevisiae -- Biotechnology , Biomass energy industries -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3955 , http://hdl.handle.net/10962/d1004014 , Sugar plantations , Sugar plantations -- South Africa , Sugar beet industry -- South Africa , Saccharomyces cerevisiae -- Biotechnology , Biomass energy industries -- South Africa
- Description: The sugar beet (Beta vulgaris) plant has in recent years been added to the Biofuel Industrial Strategy (Department of Minerals and Energy, 2007) by the South African government as a crop grown for the production of bio-ethanol. Sugar beet is commonly grown in Europe for the production of sucrose and has recently been cultivated in Cradock and the surrounding areas (Engineering News, 2008). The biofuel industry usually ferments the sucrose with Saccharomyces cerevisiae to yield bio-ethanol. However, researchers are presented with a critical role to increase current yields as there are concerns over the process costs from industrial biotechnologists. The beet factories produce a pulp by-product removed of all sucrose. The hemicellulose-rich pulp can be degraded by microbial enzymes to simple sugars that can be subsequently fermented to bio-ethanol. Thus, the pulp represents a potential source for second generation biofuel. The process of utilising microbial hemicellulases requires an initial chemical pre-treatment step to delignify the sugar beet pulp (SBP). An alkaline pre-treatment with ‘slake lime’ (calcium hydroxide) was investigated using a 23 factorial design and the factors examined were: lime load; temperature and time. The analysed results showed the highest release of reducing sugars at the pre-treatment conditions of: 0.4 g lime / g SBP; 40°C and 36 hours. A partial characterisation of the Clostridium cellulovorans hemicellulases was carried out to verify the optimal activity conditions stated in literature. The highest release of reducing sugars was measured at pH 6.5 – 7.0 and at 45°C for arabinofuranosidase A (ArfA); at pH 5.5 and 40°C for mannanase A (ManA) and pH 5.0 – 6.0 and 45°C for xylanase A (XynA). Temperature studies showed that a complete loss of enzymatic activity occurred after 11 hours for ManA; and 84-96 hours for ArfA. XynA was still active after 120 hours. The optimised lime pre-treated SBP was subsequently degraded using various combinations and percentages of C. cellulovorans ArfA, ManA and XynA to determine the maximal release of reducing sugars. Synergistically, the highest synergy was observed at 75% ArfA and 25% ManA, with a specific activity of 2.9 μmol/min/g protein. However, the highest release of sugars was observed at 4.2 μmol/min/g protein at 100% ArfA. This study has initiated the research within South Africa on SBP and its degradation by C. cellulovorans. Preliminary studies show that SBP has the potential to be utilised as a second generation biofuel source.
- Full Text:
- Date Issued: 2010
- Authors: Dredge, Roselyn Ann
- Date: 2010
- Subjects: Sugar plantations , Sugar plantations -- South Africa , Sugar beet industry -- South Africa , Saccharomyces cerevisiae -- Biotechnology , Biomass energy industries -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3955 , http://hdl.handle.net/10962/d1004014 , Sugar plantations , Sugar plantations -- South Africa , Sugar beet industry -- South Africa , Saccharomyces cerevisiae -- Biotechnology , Biomass energy industries -- South Africa
- Description: The sugar beet (Beta vulgaris) plant has in recent years been added to the Biofuel Industrial Strategy (Department of Minerals and Energy, 2007) by the South African government as a crop grown for the production of bio-ethanol. Sugar beet is commonly grown in Europe for the production of sucrose and has recently been cultivated in Cradock and the surrounding areas (Engineering News, 2008). The biofuel industry usually ferments the sucrose with Saccharomyces cerevisiae to yield bio-ethanol. However, researchers are presented with a critical role to increase current yields as there are concerns over the process costs from industrial biotechnologists. The beet factories produce a pulp by-product removed of all sucrose. The hemicellulose-rich pulp can be degraded by microbial enzymes to simple sugars that can be subsequently fermented to bio-ethanol. Thus, the pulp represents a potential source for second generation biofuel. The process of utilising microbial hemicellulases requires an initial chemical pre-treatment step to delignify the sugar beet pulp (SBP). An alkaline pre-treatment with ‘slake lime’ (calcium hydroxide) was investigated using a 23 factorial design and the factors examined were: lime load; temperature and time. The analysed results showed the highest release of reducing sugars at the pre-treatment conditions of: 0.4 g lime / g SBP; 40°C and 36 hours. A partial characterisation of the Clostridium cellulovorans hemicellulases was carried out to verify the optimal activity conditions stated in literature. The highest release of reducing sugars was measured at pH 6.5 – 7.0 and at 45°C for arabinofuranosidase A (ArfA); at pH 5.5 and 40°C for mannanase A (ManA) and pH 5.0 – 6.0 and 45°C for xylanase A (XynA). Temperature studies showed that a complete loss of enzymatic activity occurred after 11 hours for ManA; and 84-96 hours for ArfA. XynA was still active after 120 hours. The optimised lime pre-treated SBP was subsequently degraded using various combinations and percentages of C. cellulovorans ArfA, ManA and XynA to determine the maximal release of reducing sugars. Synergistically, the highest synergy was observed at 75% ArfA and 25% ManA, with a specific activity of 2.9 μmol/min/g protein. However, the highest release of sugars was observed at 4.2 μmol/min/g protein at 100% ArfA. This study has initiated the research within South Africa on SBP and its degradation by C. cellulovorans. Preliminary studies show that SBP has the potential to be utilised as a second generation biofuel source.
- Full Text:
- Date Issued: 2010
Environmental constraints affecting farmers in the Great-Kei Region
- Authors: Mtintsilana, Tando
- Date: 2010
- Subjects: Agriculture -- Environmental aspects , Agricultural ecology , Agricultural conservation , Farm management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8622 , http://hdl.handle.net/10948/1502 , Agriculture -- Environmental aspects , Agricultural ecology , Agricultural conservation , Farm management
- Description: The sustainable use of the environment for agriculture has become a global priority, requiring urgent solutions in view of intensifying competition. The South African government and the agricultural sector drafted a strategic plan for South African Agriculture. In this plan it was argued that the potential for the horizontal expansion of agricultural production is limited with one of the limitations being that unused high and medium potential land is scarce. This implies that the challenge for higher agricultural production is immense because primarily it would have to come from increased efficiency. All businesses are confronted by change at some time in their history in which agribusiness in South Africa has been subjected to changes in its past. In this era of hyper competition, agribusinesses are faced with constant change. It is how businesses deal with that change that will determine how successful they will remain in the future. The main problem of this research was to determine if farmers in the Great-Kei Region have the appropriate strategies in place to manage environmental constraints effectively. Therefore, the identification and isolation of prominent environmental constraints, through literature review and survey data gathered and analysed, would assist agribusinesses in the planning and prioritising of investments. The investment would be aimed at facilitating the development and sustainable growth in the Great-Kei Region. In this study, a quantitative, descriptive and non-experimental research design was followed. The target population of the study was farmers with farming businesses operating in the Great-Kei Region. There was data obtained from the Eastern Cape Department of Agriculture provincial office in Komga servicing the Great-Kei Region. The data obtained were lists of registered commercial farmers from the Komga iv Agricultural Association and emerging farmers operation in the region. The data obtained did not include all the farmers operating in the Great-Kei Region. The combined sum of farmers from both lists was 38 farmers (N = 38). The population N = 38 was used as a sampling frame representing the population of farmers in the Great-Kei Region. The population of this study consisted of owners or farm managers running the farming businesses and excludes other farm employees employed at the farms. Farmers with agribusinesses in the area who produced either livestock farming or crop farming or both were included for the study. The results of the survey revealed key findings, which enabled the researcher to draw meaningful conclusions and recommendations. The recommendations suggested how farmers can overcome the identified macro, micro and internal environmental constraints affecting them in the Great-Kei Region. Further identification of strategies currently employed by farmers in managing environmental constraints and the competency levels, indicated where gaps resided with strategies currently employed by farmers and where possible change would be required.
- Full Text:
- Date Issued: 2010
- Authors: Mtintsilana, Tando
- Date: 2010
- Subjects: Agriculture -- Environmental aspects , Agricultural ecology , Agricultural conservation , Farm management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8622 , http://hdl.handle.net/10948/1502 , Agriculture -- Environmental aspects , Agricultural ecology , Agricultural conservation , Farm management
- Description: The sustainable use of the environment for agriculture has become a global priority, requiring urgent solutions in view of intensifying competition. The South African government and the agricultural sector drafted a strategic plan for South African Agriculture. In this plan it was argued that the potential for the horizontal expansion of agricultural production is limited with one of the limitations being that unused high and medium potential land is scarce. This implies that the challenge for higher agricultural production is immense because primarily it would have to come from increased efficiency. All businesses are confronted by change at some time in their history in which agribusiness in South Africa has been subjected to changes in its past. In this era of hyper competition, agribusinesses are faced with constant change. It is how businesses deal with that change that will determine how successful they will remain in the future. The main problem of this research was to determine if farmers in the Great-Kei Region have the appropriate strategies in place to manage environmental constraints effectively. Therefore, the identification and isolation of prominent environmental constraints, through literature review and survey data gathered and analysed, would assist agribusinesses in the planning and prioritising of investments. The investment would be aimed at facilitating the development and sustainable growth in the Great-Kei Region. In this study, a quantitative, descriptive and non-experimental research design was followed. The target population of the study was farmers with farming businesses operating in the Great-Kei Region. There was data obtained from the Eastern Cape Department of Agriculture provincial office in Komga servicing the Great-Kei Region. The data obtained were lists of registered commercial farmers from the Komga iv Agricultural Association and emerging farmers operation in the region. The data obtained did not include all the farmers operating in the Great-Kei Region. The combined sum of farmers from both lists was 38 farmers (N = 38). The population N = 38 was used as a sampling frame representing the population of farmers in the Great-Kei Region. The population of this study consisted of owners or farm managers running the farming businesses and excludes other farm employees employed at the farms. Farmers with agribusinesses in the area who produced either livestock farming or crop farming or both were included for the study. The results of the survey revealed key findings, which enabled the researcher to draw meaningful conclusions and recommendations. The recommendations suggested how farmers can overcome the identified macro, micro and internal environmental constraints affecting them in the Great-Kei Region. Further identification of strategies currently employed by farmers in managing environmental constraints and the competency levels, indicated where gaps resided with strategies currently employed by farmers and where possible change would be required.
- Full Text:
- Date Issued: 2010
Ernesto "Che" Guevara : a psychobiographical study
- Authors: Kolesky, Candice
- Date: 2010
- Subjects: Guevara, Che, 1928-1967 , Psychology -- Biographical methods
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9864 , http://hdl.handle.net/10948/1512 , Guevara, Che, 1928-1967 , Psychology -- Biographical methods
- Description: Psychobiography is a qualitative approach to exploring and understanding the life story of an individual through the lens of psychological theory. The application of theory is typically done on the finished lives of well-known or enigmatic people. This study explores and describes the psychological development across the lifespan of Ernesto “Che” Guevara, by applying the Individual Psychology of Alfred Adler. Che Guevara was an Argentine Marxist revolutionary, physician, author, guerrilla leader, and major figure of the Cuban Revolution. Since his death, his image has become a symbol for revolution within popular culture. Extensive data has been examined in this work to ensure an accurate description of Guevara’s life. Alexander’s model of identifying salient themes was used to analyze the data within a conceptual framework derived from the theory. Guevara was fiercely loyal to his cause, at the expense of the lives of many Cuban citizens as well as his own family, whom he spent little time with. He justified this with his firmly held belief that the end justified the means and that he was always fighting for the greater good. He quite literally dedicated his life to his cause, which is the reason that he has become a modern day symbol for revolution. It is however unfortunate that this came at such a great personal expense.
- Full Text:
- Date Issued: 2010
- Authors: Kolesky, Candice
- Date: 2010
- Subjects: Guevara, Che, 1928-1967 , Psychology -- Biographical methods
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9864 , http://hdl.handle.net/10948/1512 , Guevara, Che, 1928-1967 , Psychology -- Biographical methods
- Description: Psychobiography is a qualitative approach to exploring and understanding the life story of an individual through the lens of psychological theory. The application of theory is typically done on the finished lives of well-known or enigmatic people. This study explores and describes the psychological development across the lifespan of Ernesto “Che” Guevara, by applying the Individual Psychology of Alfred Adler. Che Guevara was an Argentine Marxist revolutionary, physician, author, guerrilla leader, and major figure of the Cuban Revolution. Since his death, his image has become a symbol for revolution within popular culture. Extensive data has been examined in this work to ensure an accurate description of Guevara’s life. Alexander’s model of identifying salient themes was used to analyze the data within a conceptual framework derived from the theory. Guevara was fiercely loyal to his cause, at the expense of the lives of many Cuban citizens as well as his own family, whom he spent little time with. He justified this with his firmly held belief that the end justified the means and that he was always fighting for the greater good. He quite literally dedicated his life to his cause, which is the reason that he has become a modern day symbol for revolution. It is however unfortunate that this came at such a great personal expense.
- Full Text:
- Date Issued: 2010
Establishing a framework for an integrated, holistic, community based educational support structure
- Authors: Pieterse, Glynis
- Date: 2010
- Subjects: Curriculum planning -- South Africa , Competency-based education -- South Africa , Inclusive education -- South Africa , Teachers -- Training of -- South Africa
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9510 , http://hdl.handle.net/10948/1158 , Curriculum planning -- South Africa , Competency-based education -- South Africa , Inclusive education -- South Africa , Teachers -- Training of -- South Africa
- Description: The restructuring of South African education, after the country’s first non-racial democratic elections in 1994, coincided, with the development of inclusive education in international education. The implementation of inclusive education, internationally, was guided by the Salamanca Statement of 1994 and the international “Education for All” movement. Education White Paper 6 (2001), serves as the blueprint for implementing inclusive education in South Africa. This investigation argues that the successful implementation of the inclusive education system is dependent on the development of an effective, quality education support structure. Such an educational support structure is one that should reflect a holistic, integrated and community based approach to support. Based on this presupposition, the primary research aim of this investigation was the establishment of a framework for a holistic, integrated, community based education support structure to do justice to learners with mainly external barriers to learning (LSEN) and educators finding themselves in an inclusive classroom in Nelson Mandela Metropole and surrounding areas. In order to understand how such a framework can be established, the following guiding secondary research questions were posed: • What was the international perspective on the implementation of inclusive education? • What was the nature of educational provisioning for learners with barriers to learning (LSEN) before 1994, and the implementation of inclusive education policies thereafter? • What were the practical implications of implementing Education White Paper 6 (Department of Education, 2001) for the support roles of education support providers in South African schools? • What is the support challenges facing learners and educators within inclusive classrooms in Nelson Mandela Metropole and surrounding areas? • What support structures are currently available at the different levels of the education system? This investigation was completed from a phenomenological perspective. A constructivist approach to data collection and data analysis was followed, as the investigator did not attempt to prove or disprove theory, but rather to understand the phenomena under investigation from the viewpoint of participants. iv The sample, selected by means of non-probability purposive and theoretical sampling techniques, included 120 educators from 85 different schools in Nelson Mandela Metropole and surrounding areas. In addition, 4 education officials, 4 members of community organisations and 2 teacher union representatives were selected to the sample. Through the process of data analysis, accomplished through the principles inherent to grounded theory, two themes and sub-themes were identified. The investigator presented a discussion on the two themes and sub-themes. This discussion was followed by a proposal for the establishment of a framework for a holistic, integrated, community based educational support structure. The investigation was completed by recommendations related to the primary and secondary research questions. The investigation concluded that the implementation of inclusive education is severely hampered by strong exclusionary factors that are principally related to socio-economic backlogs that have not been successfully addressed by the current government.
- Full Text:
- Date Issued: 2010
- Authors: Pieterse, Glynis
- Date: 2010
- Subjects: Curriculum planning -- South Africa , Competency-based education -- South Africa , Inclusive education -- South Africa , Teachers -- Training of -- South Africa
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9510 , http://hdl.handle.net/10948/1158 , Curriculum planning -- South Africa , Competency-based education -- South Africa , Inclusive education -- South Africa , Teachers -- Training of -- South Africa
- Description: The restructuring of South African education, after the country’s first non-racial democratic elections in 1994, coincided, with the development of inclusive education in international education. The implementation of inclusive education, internationally, was guided by the Salamanca Statement of 1994 and the international “Education for All” movement. Education White Paper 6 (2001), serves as the blueprint for implementing inclusive education in South Africa. This investigation argues that the successful implementation of the inclusive education system is dependent on the development of an effective, quality education support structure. Such an educational support structure is one that should reflect a holistic, integrated and community based approach to support. Based on this presupposition, the primary research aim of this investigation was the establishment of a framework for a holistic, integrated, community based education support structure to do justice to learners with mainly external barriers to learning (LSEN) and educators finding themselves in an inclusive classroom in Nelson Mandela Metropole and surrounding areas. In order to understand how such a framework can be established, the following guiding secondary research questions were posed: • What was the international perspective on the implementation of inclusive education? • What was the nature of educational provisioning for learners with barriers to learning (LSEN) before 1994, and the implementation of inclusive education policies thereafter? • What were the practical implications of implementing Education White Paper 6 (Department of Education, 2001) for the support roles of education support providers in South African schools? • What is the support challenges facing learners and educators within inclusive classrooms in Nelson Mandela Metropole and surrounding areas? • What support structures are currently available at the different levels of the education system? This investigation was completed from a phenomenological perspective. A constructivist approach to data collection and data analysis was followed, as the investigator did not attempt to prove or disprove theory, but rather to understand the phenomena under investigation from the viewpoint of participants. iv The sample, selected by means of non-probability purposive and theoretical sampling techniques, included 120 educators from 85 different schools in Nelson Mandela Metropole and surrounding areas. In addition, 4 education officials, 4 members of community organisations and 2 teacher union representatives were selected to the sample. Through the process of data analysis, accomplished through the principles inherent to grounded theory, two themes and sub-themes were identified. The investigator presented a discussion on the two themes and sub-themes. This discussion was followed by a proposal for the establishment of a framework for a holistic, integrated, community based educational support structure. The investigation was completed by recommendations related to the primary and secondary research questions. The investigation concluded that the implementation of inclusive education is severely hampered by strong exclusionary factors that are principally related to socio-economic backlogs that have not been successfully addressed by the current government.
- Full Text:
- Date Issued: 2010
Estuarine use by spotted grunter Pomadasys commersonnii in a South African estuary, as determined by acoustic telemetry
- Childs, Amber-Robyn, Cowley, Paul D, Næsje, T F, Booth, Anthony J, Potts, Warren M, Thorstad, Eva B, Økland, F
- Authors: Childs, Amber-Robyn , Cowley, Paul D , Næsje, T F , Booth, Anthony J , Potts, Warren M , Thorstad, Eva B , Økland, F
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124428 , vital:35612 , https://doi.org/10.2989/A JMS.2008.30.1.12.462
- Description: Estuaries are important in the life history and the maintenance of the diversity of coastal fish species because of their function as nursery areas for juveniles as well as feeding grounds for adults (Cyrus 1991). The dependence of many fish species on estuaries is well documented (e.g. Wallace et al. 1984, Lenanton and Potter 1987, Blaber et al. 1989, Whitfield 1990, Hoss and Thayer 1993). Spotted grunter Pomadasys commersonnii (Haemulidae) (Lacepède 1801) is an estuarine-dependent species which spawns in the KwaZulu-Natal inshore coastal waters, between August and December (Wallace 1975b, Wallace and van der Elst 1975, Harris and Cyrus 1997, 1999). The eggs and larvae are transported southwards by the Agulhas Current, and juveniles between 20 mm and 50 mm TL recruit into the KwaZulu-Natal and south-eastern Cape estuaries (Wallace and van der Elst 1975, Whitfield 1990). Juvenile spotted grunter make use of the abundant food resources in estuaries, where they grow rapidly and remain for a period of 1–3 years (Wallace and Schleyer 1979, Day et al. 1981). Upon attaining sexual maturity (at between 300 mm and 400 mm TL), they return to the marine environment (Wallace 1975b). Some adults, however, return to estuaries to feed and to regain condition after spawning (Wallace 1975b, Whitfield 1994). The return of post-spawning fish coincides with increased catches by fishers in estuaries between July and January. These events are known as ‘grunter runs’ (Wallace 1975a, Marais and Baird 1980, Marais 1988, Pradervand and Baird 2002). It is suggested that adults spend up to several months in estuaries, before moving back to sea where they undergo gonadal development and ultimately spawn (Wallace 1975b, Wallace and van der Elst 1975). It is believed that adult fish also enter estuaries in a prespawning state to gain condition en route to their spawning grounds in KwaZulu-Natal (Webb 2002).
- Full Text:
- Date Issued: 2010
- Authors: Childs, Amber-Robyn , Cowley, Paul D , Næsje, T F , Booth, Anthony J , Potts, Warren M , Thorstad, Eva B , Økland, F
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124428 , vital:35612 , https://doi.org/10.2989/A JMS.2008.30.1.12.462
- Description: Estuaries are important in the life history and the maintenance of the diversity of coastal fish species because of their function as nursery areas for juveniles as well as feeding grounds for adults (Cyrus 1991). The dependence of many fish species on estuaries is well documented (e.g. Wallace et al. 1984, Lenanton and Potter 1987, Blaber et al. 1989, Whitfield 1990, Hoss and Thayer 1993). Spotted grunter Pomadasys commersonnii (Haemulidae) (Lacepède 1801) is an estuarine-dependent species which spawns in the KwaZulu-Natal inshore coastal waters, between August and December (Wallace 1975b, Wallace and van der Elst 1975, Harris and Cyrus 1997, 1999). The eggs and larvae are transported southwards by the Agulhas Current, and juveniles between 20 mm and 50 mm TL recruit into the KwaZulu-Natal and south-eastern Cape estuaries (Wallace and van der Elst 1975, Whitfield 1990). Juvenile spotted grunter make use of the abundant food resources in estuaries, where they grow rapidly and remain for a period of 1–3 years (Wallace and Schleyer 1979, Day et al. 1981). Upon attaining sexual maturity (at between 300 mm and 400 mm TL), they return to the marine environment (Wallace 1975b). Some adults, however, return to estuaries to feed and to regain condition after spawning (Wallace 1975b, Whitfield 1994). The return of post-spawning fish coincides with increased catches by fishers in estuaries between July and January. These events are known as ‘grunter runs’ (Wallace 1975a, Marais and Baird 1980, Marais 1988, Pradervand and Baird 2002). It is suggested that adults spend up to several months in estuaries, before moving back to sea where they undergo gonadal development and ultimately spawn (Wallace 1975b, Wallace and van der Elst 1975). It is believed that adult fish also enter estuaries in a prespawning state to gain condition en route to their spawning grounds in KwaZulu-Natal (Webb 2002).
- Full Text:
- Date Issued: 2010
Ethics-oriented learning in environmental education workplaces: An activity theory approach
- Authors: Olvitt, Lausanne L
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370961 , vital:66398 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122874"
- Description: In the context of increasing national and global environmental challenges and their implications for the working world, new ethics and practices are being introduced into workplaces that take better account of socio-ecological relations. Little is understood, however, about the nature of ethics-oriented workplace learning. Drawing on Cultural Historical Activity Theory (CHAT), which enables historically and contextually situated relational perspectives to emerge, this paper explores contradictions in the activity systems of two young environmental education learner-practitioners struggling to engage with the ethical dimensions of their professional work and the professional development course they are studying. The study focuses in particular on the environmental values and ethics component of their course – a year-long Learnership in Environmental Education, Training and Development Practices (EETDP). The paper reflects how tensions and contradictions within and between the interacting activity systems of the workplace, the course, and its regulating qualifications authority influence the teaching and learning of the environmental ethics component of the course. Ethics-oriented teaching and learning processes are found to be strongly influenced by the ‘rules’ and ‘mediating tools’ of these interacting systems, but these are often at odds with the ethical perspectives, socio-cultural context and skills of the ‘subject’ and ‘community’. These systemic contradictions can be more fully understood when their cultural and historical origins are made explicit. The analytical process has led to a more nuanced understanding of ethics-oriented teaching and learning in a workplace-based course, and has revealed several areas needing more careful research (particularly the area of environmental discourses) and the explicit and implicit language of ethics.
- Full Text:
- Date Issued: 2010
- Authors: Olvitt, Lausanne L
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370961 , vital:66398 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122874"
- Description: In the context of increasing national and global environmental challenges and their implications for the working world, new ethics and practices are being introduced into workplaces that take better account of socio-ecological relations. Little is understood, however, about the nature of ethics-oriented workplace learning. Drawing on Cultural Historical Activity Theory (CHAT), which enables historically and contextually situated relational perspectives to emerge, this paper explores contradictions in the activity systems of two young environmental education learner-practitioners struggling to engage with the ethical dimensions of their professional work and the professional development course they are studying. The study focuses in particular on the environmental values and ethics component of their course – a year-long Learnership in Environmental Education, Training and Development Practices (EETDP). The paper reflects how tensions and contradictions within and between the interacting activity systems of the workplace, the course, and its regulating qualifications authority influence the teaching and learning of the environmental ethics component of the course. Ethics-oriented teaching and learning processes are found to be strongly influenced by the ‘rules’ and ‘mediating tools’ of these interacting systems, but these are often at odds with the ethical perspectives, socio-cultural context and skills of the ‘subject’ and ‘community’. These systemic contradictions can be more fully understood when their cultural and historical origins are made explicit. The analytical process has led to a more nuanced understanding of ethics-oriented teaching and learning in a workplace-based course, and has revealed several areas needing more careful research (particularly the area of environmental discourses) and the explicit and implicit language of ethics.
- Full Text:
- Date Issued: 2010
Evaluating the impact of public participation on the formulation and implementation of the Integrated Development Plan: the case of the Nelson Mandela Bay Municipality (2004-2008)
- Authors: Mqulwana, Nimrod Mbuyiseli
- Date: 2010
- Subjects: City planning -- South Africa -- Port Elizabeth , Civic improvement -- South Africa -- Port Elizabeth , Regional planning -- South Africa -- Port Elizabeth , Political participation -- South Africa -- Port Elizabeth , Local government -- South Africa -- Port Elizabeth , Community development -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: vital:11638 , http://hdl.handle.net/10353/d1001247 , City planning -- South Africa -- Port Elizabeth , Civic improvement -- South Africa -- Port Elizabeth , Regional planning -- South Africa -- Port Elizabeth , Political participation -- South Africa -- Port Elizabeth , Local government -- South Africa -- Port Elizabeth , Community development -- South Africa -- Port Elizabeth
- Description: Local Government has a critical role to play in rebuilding local communities and environments as the basis for a democratic, integrated prosperous and truly non-racial society and this is enshrined in Chapter 7 of the Constitution of the Republic of South Africa Act 108 of 1996. The key focus area of this research study is the evaluation of the impact of Public Participation on the formulation and implementation of the Integrated Development Plan in the Nelson Mandela Bay Municipality for the period 2004 – 2008. This research study has two aims that are related to public participation in the Nelson Mandela Bay Municipality and they are: - To evaluate the impact of public participation in the Integrated Development Plan in the Nelson Mandela Bay Municipality and whether public participation is seen as a vehicle to enhance policy formulation and implementation or not especially with respect to community ownership of the Integrated Development Plan. To provide strategies/mechanisms to remedy the situation. The research study is people focused and the methodogical approach that is used in this investigation is qualitative and quantitative. The target groups for this research is the Community residing in the jurisdiction area of the Nelson Mandela Bay Municipality, Metro Councillors and Municipal Officials.
- Full Text:
- Date Issued: 2010
- Authors: Mqulwana, Nimrod Mbuyiseli
- Date: 2010
- Subjects: City planning -- South Africa -- Port Elizabeth , Civic improvement -- South Africa -- Port Elizabeth , Regional planning -- South Africa -- Port Elizabeth , Political participation -- South Africa -- Port Elizabeth , Local government -- South Africa -- Port Elizabeth , Community development -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: vital:11638 , http://hdl.handle.net/10353/d1001247 , City planning -- South Africa -- Port Elizabeth , Civic improvement -- South Africa -- Port Elizabeth , Regional planning -- South Africa -- Port Elizabeth , Political participation -- South Africa -- Port Elizabeth , Local government -- South Africa -- Port Elizabeth , Community development -- South Africa -- Port Elizabeth
- Description: Local Government has a critical role to play in rebuilding local communities and environments as the basis for a democratic, integrated prosperous and truly non-racial society and this is enshrined in Chapter 7 of the Constitution of the Republic of South Africa Act 108 of 1996. The key focus area of this research study is the evaluation of the impact of Public Participation on the formulation and implementation of the Integrated Development Plan in the Nelson Mandela Bay Municipality for the period 2004 – 2008. This research study has two aims that are related to public participation in the Nelson Mandela Bay Municipality and they are: - To evaluate the impact of public participation in the Integrated Development Plan in the Nelson Mandela Bay Municipality and whether public participation is seen as a vehicle to enhance policy formulation and implementation or not especially with respect to community ownership of the Integrated Development Plan. To provide strategies/mechanisms to remedy the situation. The research study is people focused and the methodogical approach that is used in this investigation is qualitative and quantitative. The target groups for this research is the Community residing in the jurisdiction area of the Nelson Mandela Bay Municipality, Metro Councillors and Municipal Officials.
- Full Text:
- Date Issued: 2010
Evaluation and management of cover crop species and their effects on weed dynamics, soil fertility and maize (Zea mays L.) productivity under irrigation in the Eastern Cape Province, South Africa
- Authors: Murungu, Farayi Solomon
- Date: 2010
- Subjects: Crops -- South Africa , Conservation of natural resources -- South Africa -- Eastern Cape , Agriculture -- South Africa -- Eastern Cape , Soil percolation -- South Africa -- Eastern Cape , Soil permeability -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape , Corn -- South Africa -- Eastern Cape , Soil fertility -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Crop Science)
- Identifier: vital:11866 , http://hdl.handle.net/10353/335 , Crops -- South Africa , Conservation of natural resources -- South Africa -- Eastern Cape , Agriculture -- South Africa -- Eastern Cape , Soil percolation -- South Africa -- Eastern Cape , Soil permeability -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape , Corn -- South Africa -- Eastern Cape , Soil fertility -- South Africa -- Eastern Cape
- Description: The current interest in conservation agriculture (CA) technologies is a result of the need to reduce excessive land degradation in most crop producing areas as well as to enhance sustainable food production. Cover crops that are usually grown under CA to provide soil cover, may offer secondary benefits, depending on the farming system. The concept of growing cover crops is a relatively new phenomenon to smallholder farmers. Production of large biomass yields and weed suppression from cover crops were major challenges affecting success and uptake of CA technologies by smallholder irrigation farmers. Coupled with this, low soil fertility limit maize productivity and reduce water use efficiency on smallholder irrigation schemes in what is largely a water strained agro-ecology in South Africa. While cover cropping can increase maize productivity, benefits of different types of mulch are not well understood, leading to challenges in selecting the most appropriate cover crop species to grow in the Eastern Cape Province (EC) of South Africa (SA) which has a warm temperate climate. With respect to any new technology, smallholder farmers are more interested in the economic benefits. Cover crops have been defined as leguminous or non-leguminous plants used for ground cover in various temporal and special configurations used in crop or animal production systems. The purpose of these cover crops is to improve on or more of the following: soil erosion, availability and cycling of N, P, K, Ca and other nutrients, soil moisture and water infiltration, and weed or pest control (Eilitta et al., 2004).. Improvement of animal or human diet may be additional goals. This definition accommodates diverse systems which may include intercrop and sole-cropping systems. In the Eastern Cape Province of South Africa, a government initiative has promoted the growing of winter cover crops in smallholder irrigation schemes (Allwood, 2006). In other parts of Africa, legume food crops have been simultaneously grown with cereal staples to improve both soil cover and human diet (Eilitta et al., 2004). Winter experiments were undertaken in 2007 and 2008 to evaluate biomass accumulation, C and N uptake, weed suppression and response to fertilization. Winter cover crops planted included; oats (Avena sativa), grazing vetch (Vicia dasycarpa), faba bean (Vicia faba), forage peas (Pisum sativum) and lupin (Lupinus angustifolius). After cover crops were terminated, the effects of residues on weeds, fertility, moisture conservation and maize productivity were undertaken in the 2007/08 and 2008/09 summer seasons. Field studies were also done in the 2007/08 and 2008/09 summer seasons to investigate effects of strip intercropping patterns (3:2; 4:2; and 6:2 patterns) of maize (cv. PAN 6479) with mucuna (Mucuna pruriens) or sunnhemp (Crotalaria juncea) on maize productivity and summer cover crop biomass production. In a separate experiment effects of relay intercropping sunnhemp, mucuna and sorghum (Sorghum bicolor) on biomass accumulation and maize productivity were investigated. Decomposition, N and P release from both winter cover crops and summer cover crops were also assessed in laboratory incubation experiments. Oats, grazing vetch and forage peas cover crops produced mean dry mass of 13873 kg/ha, 8945.5 kg/ha and 11073 kg/ha, respectively, while lupin had the lowest dry mass of 1226 kg/ha over the two seasons. Oats responded to fertilization while, there was little or no response from the other winter cover crops. Oats and grazing vetch also reduced weed density by 90 % and 80 % respectively while lupin only reduced weed density by 23 % in relation to the control plots. Nitrogen uptake was 254 kg N/ha for oats while it was 346 kg N /ha for grazing vetch. In the subsequent summer season, grazing vetch and forage pea residues significantly (P < 0.01) improved soil inorganic N. Oat and grazing vetch residues significantly (P < 0.05) reduced weed dry masss and weed species diversity compared to plots with lupin residues and the control. Lack of maize fertilization tended to reduce maize yields but not for maize grown on grazing vetch residues. From an economic perspective, grazing vetch resulted in the highest returns. Decomposition of winter cover crops was much faster for grazing vetch followed by forage peas and lastly oats. Oats had 40 % ash free dry mass remaining after 124 days while grazing vetch and forage peas had 7 % and 16 % respectively. Maximum net mineralized N and P were greater for grazing vetch (84.8 mg N/kg; 3.6 mg P/kg) compared to forage peas (66.3 mg N/kg; 2.7 mg P/ha) and oats (13.7 mg N/kg; 2.8 mg P/kg). In the strip intercropping trials, sunnhemp achieved the highest biomass yield of 4576 kg/ha in the 3:2 pattern while mucuna achieved 1897 kg/ha for the same strip pattern. The 3:2 strip intercropping pattern slightly depressed yields, however, yield reduction was more pronounced in the first season where water stress was experienced. Growing maize on previous cover crop strips failed to increase maize productivity probably due to weed growth during the fallow reducing mineral N in these strips. Decomposition was faster in sunnhemp leaves and mucuna compared to sunnhemp stems. Sunnhemp stems had about 65 % of ash free dry mass remaining after the end of the experiment at 132 days while just over 10 % of mucuna and sunnhemp leaves still remained. Mucuna mineralized 60 mg N/kg and 3.2 mg P/kg and sunnhemp mineralized 45 mg N/kg and 3.5 mg P/kg. Relay intercropping did not significantly (P > 0.05) affect maize biomass and grain yield. Sorghum experienced the largest drop in biomass when relay-intercropped with maize. Mucuna resulted in the highest N uptake (271 kg N/ha) in sole cropping while sorghum had the lowest (88 kg N/ha). Grazing vetch results in high biomass yields with minimal fertilizer application in a warm-temperate climate. Grazing vetch mulch is also the most cost effective mulch for better early weed control, improving soil mineral N status, water conservation and ultimately enhanced maize productivity in smallholder irrigation maize-based systems. The 3:2 pattern maximizes summer cover crop biomass yields compared to the 6:2 and 4:2 patterns. However, the 3:2 pattern may slightly depress yields in a water stressed environment. Relay intercropping mucuna, sunnhemp and sorghum into a maize crop at 42 days after maize sowing has no effect on maize productivity while cover crop biomass yields are low. Having a long winter fallow period after maize harvesting, a common practice in the study area, reduces the positive impact of legume cover crops on soil mineral N. Results suggest that winter cover crops may result in weed control, soil fertility and maize yield improvement benefits while a long fallow period may cancel-out these benefits for summer cover crops. Grazing vetch is a cost effective cover crop that produces high maize yields with minimal fertilizer input. Maize growing on oat mulch requires more fertilizer application than crops growing on grazing vetch mulch. Conservation agriculture systems in which summer cover crops are grown alongside the maize crop with a long winter fallow period do not produce the intended CA benefits.
- Full Text:
- Date Issued: 2010
- Authors: Murungu, Farayi Solomon
- Date: 2010
- Subjects: Crops -- South Africa , Conservation of natural resources -- South Africa -- Eastern Cape , Agriculture -- South Africa -- Eastern Cape , Soil percolation -- South Africa -- Eastern Cape , Soil permeability -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape , Corn -- South Africa -- Eastern Cape , Soil fertility -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Crop Science)
- Identifier: vital:11866 , http://hdl.handle.net/10353/335 , Crops -- South Africa , Conservation of natural resources -- South Africa -- Eastern Cape , Agriculture -- South Africa -- Eastern Cape , Soil percolation -- South Africa -- Eastern Cape , Soil permeability -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape , Corn -- South Africa -- Eastern Cape , Soil fertility -- South Africa -- Eastern Cape
- Description: The current interest in conservation agriculture (CA) technologies is a result of the need to reduce excessive land degradation in most crop producing areas as well as to enhance sustainable food production. Cover crops that are usually grown under CA to provide soil cover, may offer secondary benefits, depending on the farming system. The concept of growing cover crops is a relatively new phenomenon to smallholder farmers. Production of large biomass yields and weed suppression from cover crops were major challenges affecting success and uptake of CA technologies by smallholder irrigation farmers. Coupled with this, low soil fertility limit maize productivity and reduce water use efficiency on smallholder irrigation schemes in what is largely a water strained agro-ecology in South Africa. While cover cropping can increase maize productivity, benefits of different types of mulch are not well understood, leading to challenges in selecting the most appropriate cover crop species to grow in the Eastern Cape Province (EC) of South Africa (SA) which has a warm temperate climate. With respect to any new technology, smallholder farmers are more interested in the economic benefits. Cover crops have been defined as leguminous or non-leguminous plants used for ground cover in various temporal and special configurations used in crop or animal production systems. The purpose of these cover crops is to improve on or more of the following: soil erosion, availability and cycling of N, P, K, Ca and other nutrients, soil moisture and water infiltration, and weed or pest control (Eilitta et al., 2004).. Improvement of animal or human diet may be additional goals. This definition accommodates diverse systems which may include intercrop and sole-cropping systems. In the Eastern Cape Province of South Africa, a government initiative has promoted the growing of winter cover crops in smallholder irrigation schemes (Allwood, 2006). In other parts of Africa, legume food crops have been simultaneously grown with cereal staples to improve both soil cover and human diet (Eilitta et al., 2004). Winter experiments were undertaken in 2007 and 2008 to evaluate biomass accumulation, C and N uptake, weed suppression and response to fertilization. Winter cover crops planted included; oats (Avena sativa), grazing vetch (Vicia dasycarpa), faba bean (Vicia faba), forage peas (Pisum sativum) and lupin (Lupinus angustifolius). After cover crops were terminated, the effects of residues on weeds, fertility, moisture conservation and maize productivity were undertaken in the 2007/08 and 2008/09 summer seasons. Field studies were also done in the 2007/08 and 2008/09 summer seasons to investigate effects of strip intercropping patterns (3:2; 4:2; and 6:2 patterns) of maize (cv. PAN 6479) with mucuna (Mucuna pruriens) or sunnhemp (Crotalaria juncea) on maize productivity and summer cover crop biomass production. In a separate experiment effects of relay intercropping sunnhemp, mucuna and sorghum (Sorghum bicolor) on biomass accumulation and maize productivity were investigated. Decomposition, N and P release from both winter cover crops and summer cover crops were also assessed in laboratory incubation experiments. Oats, grazing vetch and forage peas cover crops produced mean dry mass of 13873 kg/ha, 8945.5 kg/ha and 11073 kg/ha, respectively, while lupin had the lowest dry mass of 1226 kg/ha over the two seasons. Oats responded to fertilization while, there was little or no response from the other winter cover crops. Oats and grazing vetch also reduced weed density by 90 % and 80 % respectively while lupin only reduced weed density by 23 % in relation to the control plots. Nitrogen uptake was 254 kg N/ha for oats while it was 346 kg N /ha for grazing vetch. In the subsequent summer season, grazing vetch and forage pea residues significantly (P < 0.01) improved soil inorganic N. Oat and grazing vetch residues significantly (P < 0.05) reduced weed dry masss and weed species diversity compared to plots with lupin residues and the control. Lack of maize fertilization tended to reduce maize yields but not for maize grown on grazing vetch residues. From an economic perspective, grazing vetch resulted in the highest returns. Decomposition of winter cover crops was much faster for grazing vetch followed by forage peas and lastly oats. Oats had 40 % ash free dry mass remaining after 124 days while grazing vetch and forage peas had 7 % and 16 % respectively. Maximum net mineralized N and P were greater for grazing vetch (84.8 mg N/kg; 3.6 mg P/kg) compared to forage peas (66.3 mg N/kg; 2.7 mg P/ha) and oats (13.7 mg N/kg; 2.8 mg P/kg). In the strip intercropping trials, sunnhemp achieved the highest biomass yield of 4576 kg/ha in the 3:2 pattern while mucuna achieved 1897 kg/ha for the same strip pattern. The 3:2 strip intercropping pattern slightly depressed yields, however, yield reduction was more pronounced in the first season where water stress was experienced. Growing maize on previous cover crop strips failed to increase maize productivity probably due to weed growth during the fallow reducing mineral N in these strips. Decomposition was faster in sunnhemp leaves and mucuna compared to sunnhemp stems. Sunnhemp stems had about 65 % of ash free dry mass remaining after the end of the experiment at 132 days while just over 10 % of mucuna and sunnhemp leaves still remained. Mucuna mineralized 60 mg N/kg and 3.2 mg P/kg and sunnhemp mineralized 45 mg N/kg and 3.5 mg P/kg. Relay intercropping did not significantly (P > 0.05) affect maize biomass and grain yield. Sorghum experienced the largest drop in biomass when relay-intercropped with maize. Mucuna resulted in the highest N uptake (271 kg N/ha) in sole cropping while sorghum had the lowest (88 kg N/ha). Grazing vetch results in high biomass yields with minimal fertilizer application in a warm-temperate climate. Grazing vetch mulch is also the most cost effective mulch for better early weed control, improving soil mineral N status, water conservation and ultimately enhanced maize productivity in smallholder irrigation maize-based systems. The 3:2 pattern maximizes summer cover crop biomass yields compared to the 6:2 and 4:2 patterns. However, the 3:2 pattern may slightly depress yields in a water stressed environment. Relay intercropping mucuna, sunnhemp and sorghum into a maize crop at 42 days after maize sowing has no effect on maize productivity while cover crop biomass yields are low. Having a long winter fallow period after maize harvesting, a common practice in the study area, reduces the positive impact of legume cover crops on soil mineral N. Results suggest that winter cover crops may result in weed control, soil fertility and maize yield improvement benefits while a long fallow period may cancel-out these benefits for summer cover crops. Grazing vetch is a cost effective cover crop that produces high maize yields with minimal fertilizer input. Maize growing on oat mulch requires more fertilizer application than crops growing on grazing vetch mulch. Conservation agriculture systems in which summer cover crops are grown alongside the maize crop with a long winter fallow period do not produce the intended CA benefits.
- Full Text:
- Date Issued: 2010
Evaluation and mapping of the spatial variability of soil fertility at Zanyokwe Irrigation Scheme in the Eastern Cape, South Africa
- Authors: Manyevere, Alen
- Date: 2010
- Subjects: Soil surveys -- South Africa -- Eastern Cape , Irrigation farming -- South Africa , Soil fertility -- South Africa -- Eastern Cape , Soils -- Analysis , Soils -- Testing , Crop yields , Soils Classification
- Language: English
- Type: Thesis , Masters , MSc Agric (Soil Science)
- Identifier: vital:11176 , http://hdl.handle.net/10353/d1001019 , Soil surveys -- South Africa -- Eastern Cape , Irrigation farming -- South Africa , Soil fertility -- South Africa -- Eastern Cape , Soils -- Analysis , Soils -- Testing , Crop yields , Soils Classification
- Full Text: false
- Date Issued: 2010
- Authors: Manyevere, Alen
- Date: 2010
- Subjects: Soil surveys -- South Africa -- Eastern Cape , Irrigation farming -- South Africa , Soil fertility -- South Africa -- Eastern Cape , Soils -- Analysis , Soils -- Testing , Crop yields , Soils Classification
- Language: English
- Type: Thesis , Masters , MSc Agric (Soil Science)
- Identifier: vital:11176 , http://hdl.handle.net/10353/d1001019 , Soil surveys -- South Africa -- Eastern Cape , Irrigation farming -- South Africa , Soil fertility -- South Africa -- Eastern Cape , Soils -- Analysis , Soils -- Testing , Crop yields , Soils Classification
- Full Text: false
- Date Issued: 2010
Evaluation of antidiarrhoeal and toxicological properties of Hermannia Incana cav.: a South African medicinal plant
- Authors: Appidi, Jaipal Reddy
- Date: 2010
- Subjects: Sterculiaceae , Medicinal plants -- South Africa -- Eastern Cape , Diarrhea , Botany, Medical
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11304 , http://hdl.handle.net/10353/259 , Sterculiaceae , Medicinal plants -- South Africa -- Eastern Cape , Diarrhea , Botany, Medical
- Description: Hermannia incana Cav. (Sterculiaceae), known as sweet yellow bells, is a medicinal plant used by the people of the Eastern Cape for the treatment of stomach-ache and diarrhoea. It has purgative and diaphoretic effects. It is a prostrate herb with yellow flowers and sparsely hairy and slightly glandular leaves, occurring in grassland and marshes in the Eastern Cape Province of South Africa. Based on the ethnomedical uses of this plant, the research project was designed to evaluate its antidiarrhoeal and toxicological properties. An ethnobotanical study of plants used for the treatment of diarrhoea in the Eastern Cape Province was carried out, using a questionnaire which was administered to herbalists, traditional healers and rural dwellers. This survey indicated a total of 17 plant species from 14 families. Elephantorrhiza elephantine (Burch.) Skeels, Hermannia incana Cav., Pelargonium reniforme Curt., Alepidea amatymbica Eckl. & Zeyh. and Bulbine latifolia (L.f.) Roem. et Schult. were the most frequently mentioned and highly recommended plants for the treatment of diarrhoea by both the traditional healers and rural dwellers. The root, bark and leaves are the common parts of plants used, while decoctions and infusions are the main methods of preparation. The agar dilution method was used to study the antimicrobial activity. The methanol extracts of the plant showed appreciable activity against Gram-positive and Gram-negative bacteria at concentrations ranging from 0.5 to 7.0 mg/ml. The acetone and water extracts of both the leaves and the roots showed moderate activity against Gram positive bacteria and less activity against Gram negative bacteria. All the extracts inhibited the growth of the fungi Aspergillus flavus, Aspergillus niger, and Mucor hiemalis with growth inhibition ranging from 54.31 percent to 96.67 percent at 0.1-10 mg/ml. None of the extracts suppressed the growth of Candida albicans at the maximum concentration (10 mg/ml) tested. iii In the in vivo antidiarrhoeal evaluation using Wistar rats, the aqueous extract at all the doses tested, significantly prolonged the time of induction of diarrhoea and also reduced the frequency of diarrhoeal episodes and fecal parameters (total number, number of wet, fresh and dry weight and water content of the faeces). The percentage inhibition of defecation and intestinal content (enteropooling) were increased in dose dependent manner. The doses also reduced the intestinal transit time of charcoal, masses and volumes of intestinal fluid (gastrointestinal motility). These results are indications of antidiarrhoeal property of H. incana leaf extract with the 600 mg/kg body weight of the extract being the most effective. In the toxicological evaluation using Wistar rats, the oral administration of the extract did not produce any significant effect on the liver and kidney body weight ratios, RBC, HB, PCV, MCV MCH, MCHC, RCDW, WBC, neutrophils, monocytes and basophils cholesterol, triacylglycerol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and atherogenic index. The extract also did not affect the levels of sodium, potassium, chloride, inorganic phosphorus, urea, creatinine, total protein, globulin, albumin, total and conjugated bilirubin. The activities of alkaline phosphatase, gamma glutamyl transferase and alanine aminotransaminase in the serum were increased by the extract whereas aspartate aminotransaminase was decreased. The levels of LUC, platelets, lymphocytes and eosinophils were significantly affected at 600 mg/kg body weight. The available evidence in this study suggests that the extract of H. incana leaf is mild, parameter and dose specific. The structure and distribution of foliar appendages on the leaves of this plant were investigated with the JEOL (JSM-6390LV) scanning electron microscope (SEM). Both glandular and non-glandular trichomes were observed. Long stalked glandular trichomes were present on both the abaxial and adaxial surfaces while short stalked glandular trichomes were present only on the adaxial surface. Glandular trichomes were capitate while nonglandular trichomes were stellate with many arms. Energy dispersive X-ray spectroscopyiv SEM showed that Al, Ca, K, Na, Ti and Si were the major constituents of the crystals analyzed from the leaf surfaces. The phytochemical screening of H. incana revealed the presence of bioactive antidiarrhoeal agents such as alkaloids, tannins, saponins, phenolics, triterpenes, cardiac glycosides, flavonoids, cardenolides and dienolides. Two flavonoids, epicatechin and 3, 5, 7, 2’ tetra-hydroxy flavone-3- O--D-glucopyranoside were isolated from the leaves of the plant through bio-active guided fractionation. Both these compounds were screened against diarrhoea causative organisms (Echerichia coli, Shigella flexneri, Bacillus cereus and Staphylococcus aureus) and exhibiting minimum inhibitory concentrations ranging from 12.5 to 100 μg/ml. The findings from this research have generally justified the traditional use of this plant for the treatment of diarrhoea in this province.
- Full Text:
- Date Issued: 2010
- Authors: Appidi, Jaipal Reddy
- Date: 2010
- Subjects: Sterculiaceae , Medicinal plants -- South Africa -- Eastern Cape , Diarrhea , Botany, Medical
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11304 , http://hdl.handle.net/10353/259 , Sterculiaceae , Medicinal plants -- South Africa -- Eastern Cape , Diarrhea , Botany, Medical
- Description: Hermannia incana Cav. (Sterculiaceae), known as sweet yellow bells, is a medicinal plant used by the people of the Eastern Cape for the treatment of stomach-ache and diarrhoea. It has purgative and diaphoretic effects. It is a prostrate herb with yellow flowers and sparsely hairy and slightly glandular leaves, occurring in grassland and marshes in the Eastern Cape Province of South Africa. Based on the ethnomedical uses of this plant, the research project was designed to evaluate its antidiarrhoeal and toxicological properties. An ethnobotanical study of plants used for the treatment of diarrhoea in the Eastern Cape Province was carried out, using a questionnaire which was administered to herbalists, traditional healers and rural dwellers. This survey indicated a total of 17 plant species from 14 families. Elephantorrhiza elephantine (Burch.) Skeels, Hermannia incana Cav., Pelargonium reniforme Curt., Alepidea amatymbica Eckl. & Zeyh. and Bulbine latifolia (L.f.) Roem. et Schult. were the most frequently mentioned and highly recommended plants for the treatment of diarrhoea by both the traditional healers and rural dwellers. The root, bark and leaves are the common parts of plants used, while decoctions and infusions are the main methods of preparation. The agar dilution method was used to study the antimicrobial activity. The methanol extracts of the plant showed appreciable activity against Gram-positive and Gram-negative bacteria at concentrations ranging from 0.5 to 7.0 mg/ml. The acetone and water extracts of both the leaves and the roots showed moderate activity against Gram positive bacteria and less activity against Gram negative bacteria. All the extracts inhibited the growth of the fungi Aspergillus flavus, Aspergillus niger, and Mucor hiemalis with growth inhibition ranging from 54.31 percent to 96.67 percent at 0.1-10 mg/ml. None of the extracts suppressed the growth of Candida albicans at the maximum concentration (10 mg/ml) tested. iii In the in vivo antidiarrhoeal evaluation using Wistar rats, the aqueous extract at all the doses tested, significantly prolonged the time of induction of diarrhoea and also reduced the frequency of diarrhoeal episodes and fecal parameters (total number, number of wet, fresh and dry weight and water content of the faeces). The percentage inhibition of defecation and intestinal content (enteropooling) were increased in dose dependent manner. The doses also reduced the intestinal transit time of charcoal, masses and volumes of intestinal fluid (gastrointestinal motility). These results are indications of antidiarrhoeal property of H. incana leaf extract with the 600 mg/kg body weight of the extract being the most effective. In the toxicological evaluation using Wistar rats, the oral administration of the extract did not produce any significant effect on the liver and kidney body weight ratios, RBC, HB, PCV, MCV MCH, MCHC, RCDW, WBC, neutrophils, monocytes and basophils cholesterol, triacylglycerol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and atherogenic index. The extract also did not affect the levels of sodium, potassium, chloride, inorganic phosphorus, urea, creatinine, total protein, globulin, albumin, total and conjugated bilirubin. The activities of alkaline phosphatase, gamma glutamyl transferase and alanine aminotransaminase in the serum were increased by the extract whereas aspartate aminotransaminase was decreased. The levels of LUC, platelets, lymphocytes and eosinophils were significantly affected at 600 mg/kg body weight. The available evidence in this study suggests that the extract of H. incana leaf is mild, parameter and dose specific. The structure and distribution of foliar appendages on the leaves of this plant were investigated with the JEOL (JSM-6390LV) scanning electron microscope (SEM). Both glandular and non-glandular trichomes were observed. Long stalked glandular trichomes were present on both the abaxial and adaxial surfaces while short stalked glandular trichomes were present only on the adaxial surface. Glandular trichomes were capitate while nonglandular trichomes were stellate with many arms. Energy dispersive X-ray spectroscopyiv SEM showed that Al, Ca, K, Na, Ti and Si were the major constituents of the crystals analyzed from the leaf surfaces. The phytochemical screening of H. incana revealed the presence of bioactive antidiarrhoeal agents such as alkaloids, tannins, saponins, phenolics, triterpenes, cardiac glycosides, flavonoids, cardenolides and dienolides. Two flavonoids, epicatechin and 3, 5, 7, 2’ tetra-hydroxy flavone-3- O--D-glucopyranoside were isolated from the leaves of the plant through bio-active guided fractionation. Both these compounds were screened against diarrhoea causative organisms (Echerichia coli, Shigella flexneri, Bacillus cereus and Staphylococcus aureus) and exhibiting minimum inhibitory concentrations ranging from 12.5 to 100 μg/ml. The findings from this research have generally justified the traditional use of this plant for the treatment of diarrhoea in this province.
- Full Text:
- Date Issued: 2010
Evaluation of cover crop species for biomass production, weed suppression and maize yields under irrigation in the Eastern Cape Province, South Africa
- Authors: Musunda, Bothwell Zvidzai
- Date: 2010
- Subjects: Cover crops , Biomass energy -- South Africa -- Eastern Cape , No-tillage , Conservation of natural resources -- South Africa -- Eastern Cape , Agriculture -- South Africa -- Eastern Cape , Agricultural systems -- South Africa -- Eastern Cape , Weeds
- Language: English
- Type: Thesis , Masters , MSc Agric (Crop Science)
- Identifier: vital:11867 , http://hdl.handle.net/10353/347 , Cover crops , Biomass energy -- South Africa -- Eastern Cape , No-tillage , Conservation of natural resources -- South Africa -- Eastern Cape , Agriculture -- South Africa -- Eastern Cape , Agricultural systems -- South Africa -- Eastern Cape , Weeds
- Description: Achieving high biomass yields of cover crops has been a challenge to the success of Conservation Agriculture (CA) practices in the Eastern Cape (EC). A study was conducted to evaluate strategies for optimizing cover crop biomass production. Trials were carried out to screen summer and winter cover crops, as well as evaluate intercropping patterns and planting dates for biomass, weed suppression and subsequent maize yield under irrigation. Four summer legume cover crop species were evaluated under a Randomised Complete Block Design (RCBD) design. The cover crops were fertilized with 13.34 kg ha-1 of N, 20 kg ha-1 P and 26.66 kg ha-1 K. In the 2008/09 summer season a maize crop was superimposed on the 2007/08 screening trial under no-till. The crop was fertilized with 60 kg ha-1 of N. An intercropping trial was conducted over two seasons as a way of investigating the best way of incorporating cover crops into farmers cropping systems. This was done bearing in mind the limitation of resources such as land. The trial evaluated 3 factors laid as a 2 x 2 x 3 factorial arranged in a split-plot design. The main factor was cover crop planting date (planting at maize planting or 2 weeks after maize planting). The sub plot factor was intercropping pattern (strip intercropping and between row intercropping). A trial was also conducted to evaluate the effect of planting date (End of April and mid May) and four winter legume cover crop species on cover crop biomass, weed suppression and maize grain yield. The experiment was laid out as a Randomised Complete Block Design (RCBD) replicated 3 times. In the subsequent summer season a maize crop was superimposed on the winter trial to test the residual effects of the cover crop species. Another study was conducted to evaluate winter cereal cover crop species for biomass accumulation, weed suppression and subsequent maize grain yield. The cover crops as well as a weedy fallow control plot treatments were laid out as a Randomised Complete Block Design replicated 3 times. In the subsequent summer season a maize crop was superimposed on the site under no-till to evaluate the residual effect of the cover crops on maize. The results showed sunhemp, cowpea and lablab as the best cover crops with high biomass and weed suppression whilst mucuna was the least. Sunhemp consistently yielded higher cover biomass averaging 11200 kg ha-1 over the two seasons whilst mucuna had a consistently lowest average biomass yield of 4050 kg ha-1. These cover crops were above the critical 6 t ha-1 for effective weed suppression. There was a significant (p<0.01) relationship of cover crop dry weight and weed dry weight in both seasons. Subsequent maize grain yield was significantly higher in the sunhemp plots (64.2 %) than the weedy fallow plot. Mucuna, lablab and cowpea had maize grain yield increases of 16.6%, 33% and 43.2% respectively. Intercropping cover crops at maize planting yielded higher cover crop dry weights than a delay in intercropping cover crops. A delay in intercropping resulted in significantly higher average maize grain yield of 4700 kg ha-1 compared to intercropping at maize planting (3800 kg ha-1) and sole maize (4300 kg ha-1) over the two seasons. Strip intercropping also yielded higher (5000 kg ha- 1) average maize grain yield compared to row intercropping (3600 kg ha-1) and sole maize (4300 kg ha-1). There was a significant (p<0.05) relationship between cover crop dry weight in the 2007/08 season and maize grain yield in the 2008/09 season. Early planting grazing vetch gave the highest biomass yield of 8100 kg ha-1 whilst early planted red clover had the lowest biomass of 635 kg ha-1. Low weed dry weights were also obtained from the early planted grazing vetch as opposed to the other treatments. There was a significant (p<0.001) relationship of cover crop dry weight and weed dry weight. In the subsequent 2008/09 summer season early planted grazing vetch had the highest maize yield of 7500 kg ha-1 which was 56.3 % more than the weedy fallow plot had 4800 kg ha-1. The weedy fallow plot also had high weed infestation than the cover crop plots. There were significant (p<0.01) relationships between cover crop dry weight and maize grain yield, winter weed dry weight and maize grain yield and summer weed dry weight and maize grain yield. The results also showed triticale (13900 kg ha-1) as the best winter cover crop for biomass production. Italian ryegrass (6500 kg ha-1) produced the least amount of biomass. In The subsequent maize crop white oats gave highest maize grain yield (6369 kg ha-1) which was 33 % more than the weedy fallow plot (4784 kg ha- 1). There were also significant (p< 0.01) relationships of maize grain yield and winter weed dry weight, maize grain yield and summer growing weeds. The various studies demonstrated that there is opportunity for high biomass production under small scale farmers irrigated conditions using cover crops both in winter and summer. Best bet cover crops were sunhemp, cowpea and lablab for summer and triticale, white oats, barley, Italian ryegrass and grazing vetch for winter. Cover crops can also be incorporated into farmers cropping systems as sole crops or intercrops within the maize based cropping systems. Strip intercropping can be used by farmers as a way of introducing cover crops. Critical to achievement of high biomass is the time of planting cover crops with high biomass when planting is done early. A 2 week delay in strip intercropping cover crop into maize can be used as a way of incorporating cover crops into farmers cropping systems with minimal maize yield reduction.
- Full Text:
- Date Issued: 2010
- Authors: Musunda, Bothwell Zvidzai
- Date: 2010
- Subjects: Cover crops , Biomass energy -- South Africa -- Eastern Cape , No-tillage , Conservation of natural resources -- South Africa -- Eastern Cape , Agriculture -- South Africa -- Eastern Cape , Agricultural systems -- South Africa -- Eastern Cape , Weeds
- Language: English
- Type: Thesis , Masters , MSc Agric (Crop Science)
- Identifier: vital:11867 , http://hdl.handle.net/10353/347 , Cover crops , Biomass energy -- South Africa -- Eastern Cape , No-tillage , Conservation of natural resources -- South Africa -- Eastern Cape , Agriculture -- South Africa -- Eastern Cape , Agricultural systems -- South Africa -- Eastern Cape , Weeds
- Description: Achieving high biomass yields of cover crops has been a challenge to the success of Conservation Agriculture (CA) practices in the Eastern Cape (EC). A study was conducted to evaluate strategies for optimizing cover crop biomass production. Trials were carried out to screen summer and winter cover crops, as well as evaluate intercropping patterns and planting dates for biomass, weed suppression and subsequent maize yield under irrigation. Four summer legume cover crop species were evaluated under a Randomised Complete Block Design (RCBD) design. The cover crops were fertilized with 13.34 kg ha-1 of N, 20 kg ha-1 P and 26.66 kg ha-1 K. In the 2008/09 summer season a maize crop was superimposed on the 2007/08 screening trial under no-till. The crop was fertilized with 60 kg ha-1 of N. An intercropping trial was conducted over two seasons as a way of investigating the best way of incorporating cover crops into farmers cropping systems. This was done bearing in mind the limitation of resources such as land. The trial evaluated 3 factors laid as a 2 x 2 x 3 factorial arranged in a split-plot design. The main factor was cover crop planting date (planting at maize planting or 2 weeks after maize planting). The sub plot factor was intercropping pattern (strip intercropping and between row intercropping). A trial was also conducted to evaluate the effect of planting date (End of April and mid May) and four winter legume cover crop species on cover crop biomass, weed suppression and maize grain yield. The experiment was laid out as a Randomised Complete Block Design (RCBD) replicated 3 times. In the subsequent summer season a maize crop was superimposed on the winter trial to test the residual effects of the cover crop species. Another study was conducted to evaluate winter cereal cover crop species for biomass accumulation, weed suppression and subsequent maize grain yield. The cover crops as well as a weedy fallow control plot treatments were laid out as a Randomised Complete Block Design replicated 3 times. In the subsequent summer season a maize crop was superimposed on the site under no-till to evaluate the residual effect of the cover crops on maize. The results showed sunhemp, cowpea and lablab as the best cover crops with high biomass and weed suppression whilst mucuna was the least. Sunhemp consistently yielded higher cover biomass averaging 11200 kg ha-1 over the two seasons whilst mucuna had a consistently lowest average biomass yield of 4050 kg ha-1. These cover crops were above the critical 6 t ha-1 for effective weed suppression. There was a significant (p<0.01) relationship of cover crop dry weight and weed dry weight in both seasons. Subsequent maize grain yield was significantly higher in the sunhemp plots (64.2 %) than the weedy fallow plot. Mucuna, lablab and cowpea had maize grain yield increases of 16.6%, 33% and 43.2% respectively. Intercropping cover crops at maize planting yielded higher cover crop dry weights than a delay in intercropping cover crops. A delay in intercropping resulted in significantly higher average maize grain yield of 4700 kg ha-1 compared to intercropping at maize planting (3800 kg ha-1) and sole maize (4300 kg ha-1) over the two seasons. Strip intercropping also yielded higher (5000 kg ha- 1) average maize grain yield compared to row intercropping (3600 kg ha-1) and sole maize (4300 kg ha-1). There was a significant (p<0.05) relationship between cover crop dry weight in the 2007/08 season and maize grain yield in the 2008/09 season. Early planting grazing vetch gave the highest biomass yield of 8100 kg ha-1 whilst early planted red clover had the lowest biomass of 635 kg ha-1. Low weed dry weights were also obtained from the early planted grazing vetch as opposed to the other treatments. There was a significant (p<0.001) relationship of cover crop dry weight and weed dry weight. In the subsequent 2008/09 summer season early planted grazing vetch had the highest maize yield of 7500 kg ha-1 which was 56.3 % more than the weedy fallow plot had 4800 kg ha-1. The weedy fallow plot also had high weed infestation than the cover crop plots. There were significant (p<0.01) relationships between cover crop dry weight and maize grain yield, winter weed dry weight and maize grain yield and summer weed dry weight and maize grain yield. The results also showed triticale (13900 kg ha-1) as the best winter cover crop for biomass production. Italian ryegrass (6500 kg ha-1) produced the least amount of biomass. In The subsequent maize crop white oats gave highest maize grain yield (6369 kg ha-1) which was 33 % more than the weedy fallow plot (4784 kg ha- 1). There were also significant (p< 0.01) relationships of maize grain yield and winter weed dry weight, maize grain yield and summer growing weeds. The various studies demonstrated that there is opportunity for high biomass production under small scale farmers irrigated conditions using cover crops both in winter and summer. Best bet cover crops were sunhemp, cowpea and lablab for summer and triticale, white oats, barley, Italian ryegrass and grazing vetch for winter. Cover crops can also be incorporated into farmers cropping systems as sole crops or intercrops within the maize based cropping systems. Strip intercropping can be used by farmers as a way of introducing cover crops. Critical to achievement of high biomass is the time of planting cover crops with high biomass when planting is done early. A 2 week delay in strip intercropping cover crop into maize can be used as a way of incorporating cover crops into farmers cropping systems with minimal maize yield reduction.
- Full Text:
- Date Issued: 2010