Agronomic methods for Striga (Striga asiatica) control in dryland maize in Limpopo Province

Thesis (M. Sc. Agriculture (Crop Science)) -- University of Limpopo, 2008Striga control through agronomic practices is the key to maize production predominantly in small holder farmers who cannot afford chemical weed control. Striga has affected maize yield in many areas in Limpopo Province, South Africa. Field experiments were carried out over one season at three sites to determine the effect of weed control method on striga on maize. The experiment was done at Mafarana village (Mopani District) near Tzaneen where striga is a serious problem. It was conducted on three fields, belonging to Mrs. Shingwenyana, Mr. Nyathi and Mr. Mushwana. A randomized complete block design experiment was laid out consisting of two factors; (i) two maize cultivars i.e. Zm 1421 and Zm 423 (ii) three agronomic practices: hand hoeing alone (as the control factor), hand hoeing plus inorganic fertilization using lime ammonium nitrate (LAN-28%N) at the rate of 56kg/ha, and hand hoeing plus inter-row intercropping of maize with cowpea. Cowpea cultivar Bechuana White was used for the experiment. The results indicated that the effect of the method of weed control on the number of striga plants was significant at the 5% level of significance at all locations except at Mushwana’s where at 105 days after planting (DAP) there was no significant effect. Striga numbers were lower in hand hoed plus inorganic fertilizer plots compared to hand hoed alone and hand hoed plus intercropping. At Shingwenyana’s field the results indicated that effect of weed control methods on grain yield was significant and this is where the striga numbers were the highest than at Mushwana and Nyathi’s fields. The effect of weed control methods on grain yield was significant only at Shingwenyana’s field ranging from 2219kg/ha (hand hoeing), 2248kg/ha (hand hoeing plus inorganic fertilizer) to 3928kg/ha (hand hoeing plus intercropping). The effect of weed control method on shelling %, hundred seed weight, number of cobs per plant and lodging % was not significant. The effect of weed control method on number of plants per plot was significant at Mushwana’s field only. There was significant difference of striga numbers among maize varieties at Nyathi’s field at 105 DAP. In hand hoed, striga numbers were 0.075 for Zm 1421 and 0.489 for Zm 423. Plots that were hand hoed plus inorganic fertilizer application striga numbers were 0.075 for Zm 1421 and 0.270 for Zm 423 and finally hand hoed plus intercropped plots with maize and cowpeas had striga numbers of 0.739 for 1421 and 0.850 for ZM 423. It is recommended that farmers improve the fertility status of their soils in order to control striga problem.Limpopo Department of Agricultur

Evaluation of genotype x environment interaction using GGE-biplot on dry beans (Phaseolus vulgaris L.) in Limpopo province of South Africa

Dry bean is the second most important legume crop in South Africa due to its high protein content. GGE- Biplot was used to evaluate genotype x environment interaction (GEI) and stability performance of dry bean genotypes during 2011 and 2012 growing seasons. Eight dry bean genotypes were planted at different locations in the Limpopo province, South Africa with different agro-climatic characteristics. The genotypes used were OPS-RS1, Jenny, Kranskop, DBS310, OPS-RS4, DBS 360, OPS-RS2 and OPS-RS5. The ANOVA analysis results for grain yield, number of pods per plant and number of seeds per plant revealed that the environment contributed more to the total variation followed by GEI and finally genotype. According to GGE biplot for grain yield, OPS- RS1 was regarded as the more stable genotype and had the highest mean yield, DBS 360 had the highest mean number of pods per plant and DBS 310 produced the highest mean number of seeds per plant. The GGE biplot methodology clearly presented the GEI relationship among environments and genotypes.The Limpopo Department of Agriculture and Rural developmenthttp://www.cropj.com/about.htmlam2017Plant Production and Soil Scienc

Effects of heat-moisture treatment on the thermal, functional properties and composition of cereal, legume and tuber starches: a review

Several methods are currently employed in the modification of starch obtained from different botanical sources. Starch in its native form is limited in application due to retrogradation, syneresis, inability to withstand shear stress as well as its unstable nature at varying temperatures and pH environment. Modification of starch is therefore needed to enhance its food and industrial application. A primary and safe means of modifying starch for food and industrial use is through hydrothermal methods which involves heat-moisture treatment and annealing. Heat-moisture treatment (HMT) is a physical modification technique that improves the functional and physicochemical properties of starch without changing its molecular composition. Upon modification through HMT, starches from cereals, legumes and tuber crops serve as important ingredients in diverse food, pharmaceutical and industrial processes. Although changes in starch initiated by HMT have been studied in starches of different plant origin, this work further provides insight on the composition, thermal and functional properties of heat-moisture treated starch obtained from cereals, legumes and tuber crops

The effect of drought stress on yield, leaf gaseous exchange and chlorophyll fluorescence of dry beans (Phaseolus vulgaris L.)

Global food production relies on irrigation, especially in low rainfall areas such as South Africa. The study was conducted to determine the effect of drought stress on growth, yield, leaf gaseous exchange and chlorophyll fluorescence parameters of dry bean under field conditions and the after effects of drought stress upon lifting drought stress. A rain shelter field trial was conducted at the Hatfield Experimental Farm of the University of Pretoria, Pretoria, South Africa. Dry bean cultivar DBS 360 was subjected to five levels of moisture stress arranged in a randomized complete block design with six replications. The plants were exposed to the following drought stress levels: the control: Irrigated to field capacity (S1), Withholding irrigation from 36 days after planting (DAP) for 24 days (S2), Withholding irrigation from 49 DAP for 24 days (S3), Withholding irrigation from 73 DAP to the end of the growing season (S4) and irrigated to field capacity on a fortnightly bases for the rest of the season from 36 DAP to the end of the growing season (S5).The results revealed that drought stress reduced dry matter production, leaf area index, number of pods per plant, number of seeds per plant, hundred seed weight and grain yield. Treatments S1, S4 and S5 produced statistically similar grain yield. Drought stress towards the end of the growing season may not cause serious harm in grain yield. Drought stress resulted in a reduction in photosynthetic rate, intercellular carbon dioxide concentration, stomatal conductance and transpiration. Chlorophyll fluorescence was also affected by drought stress. The highest WUE was found in the treatment which was irrigated on fortnightly bases from 36 DAP. This indicates that with appropriate irrigation it is possible to save water without a great yield loss in dry bean.http://www.elsevier.com/locate/agwat2018-01-31hb2017Plant Production and Soil Scienc

Influence of head-moisture treatment on functional, colour and thermal properties of bambara ground-nut starch

MSCFSTDepartment of Science and TechnologyHeat-moisture treatment (HMT) is a physical modification that alters the physicochemical properties of starch without changing its molecular structure. The objective of the study was to investigate the influence of HMT on the functional, colour and thermal properties of bambara groundnut (BG) starch. A central composite rotatable design comprising two independent factors (temperature and time) was used for the study. The central composite rotatable design was generated using Design-Expert software version 8.0.1.0. Bambara starch extraction was done by milling BG into flour (5 Kg), suspension in 15 L, 0.3% sodium hydroxide and centrifugation followed by washing using distilled water. The starch was then HMT treated in an air oven at 80 - 120 °C for 30 - 90 min under 15 % moisture content (MC) (HMT 15), 25% MC (HMT 25) and 35% MC (HMT 35). The highest L* and WI values for HMT treated BG starch were observed at HMT 80 °C for 30 min under 15% MC; 100 °C for 60 min (25% MC); and 100 °C for 17.57 min (35% MC) while the lowest was observed in HMT 100 °C for 102.43 min (15% MC); 120 °C for 90 min (25% MC); and 120 °C for 90 min (35% MC). In HMT 15-BG starch, the gelatinisation parameters onset (To), peak (Tp) and concluding temperature (Tc) of the samples decreased as treatment time and temperature increased whereas gelatinisation enthalpy of BG starch increased with increase in HMT treatment temperature and time. In HMT 25-BG starch Tp, and gelatinisation enthalpy of the starch increased with increase in HMT treatment temperature and time. While in HMT 35-BG starch, To, Tp, Tc and gelatinisation enthalpy of the starches decreased with increase in HMT treatment temperature and time. In HMT 15-BG starch, the water absorption capacity (WAC), solubility and swelling power (SP) decreased as treatment time and temperature increased while oil absorption capacity (OAC) of the starch increased with increase in HMT treatment temperature and time. In terms of HMT 25-BG starch, the WAC and OAC increased as HMT treatment time and temperature increased while SP and solubility of the starch decreased with increase in HMT treatment temperature and time. In HMT 35-BG starch, OAC, solubility and SP decreased as treatment time and temperature increased while WAC of the starch increased with increase in HMT treatment temperature and time. The optimum HMT conditions for BG starch were found to be 80 °C for 30 min (HMT 15), 105.74 °C for 30 min (HMT 25), and 113.16 °C for 30 min (HMT 35). Desirability of the obtained optimum conditions were 0.63 (HMT 15), 0.56 (HMT 25) and 0.64 (HMT 35). Information obtained from scanning electron micrograph indicates oval and round shape for bambara starch granules, with varying sizes. The range of the granule size width was 4.2 – 4.7 mm and 10 μm for length. The modified starches showed some changes in granule morphology as they seem to disintegrate with application of HMT. Unmodified and HMT - BG starches showed characteristic FTIR bands linked with common starches. All the samples displayed complex vibrations in the region below 1000 cm-1 due to the skeletal vibrations of the glucose pyranose ring. Statistical analysis on colour, thermal and functional properties of HMT 15-BG, HMT 25-BG and HMT 35-BG starch showed that effects of temperature and treatment time had no significant (p ≥ 0.05) effect on these properties of HMT-BG starch. However, treatment time had a significant linear effect (p ≤ 0.05) on swelling power, for HMT 15-BG starch. In HMT 35-BG starch, WAC was significantly affected by quadratic effect of temperature and time while solubility was significantly affected by linear effect of time and quadratic effect of temperature.NR

Expression of TN5 transposase for next generation sequencing protocol of HIV ad selected oncoviruses

MSc (Microbiology)Department of MicrobiologyObjective: The development of HIV drug resistance is a significant challenge in maintaining suppressed viral load in the management of patients. Next generation sequencing (NGS) is a more sensitive approach to determine the burden of HIV drug resistance. We aimed to describe the uptake of NGS in HIV drug resistance studies in Africa. Methodology: Electronic search was done for studies published between 2005 and 2019, from three databases: Pubmed, Web of Science and Google scholar. The search approach was carried out according to PRISMA guidelines. Studies included in the analysis were those that reported the use of NGS on HIV drug resistance using samples from Africa or in which the studies were done in Africa. Only articles published in English were included in the analysis. Results: Four thousand one hundred and eighty articles were identified according to the search criteria. Out of these, 238 studies met the inclusion criteria and were included in the analysis. Thirty studies (12.6%) used NGS, 194 (81.5%) used Sanger sequencing, and 14 (5.9%) used both techniques. Evidence of in-country application of NGS was observed in six studies (13.6%), all from South Africa. In other studies, NGS was either done outside of Africa using samples obtained from Africa or the country in which NGS was done was not indicated. From 2005 to 2012, only one study was reported on HIV drug resistance using NGS; however, 44 studies were published by 2019. Out of the 54 African countries, investigators from 13 countries (24.1%) published data on HIV drug resistance using NGS, as at end of 2019. Conclusion: There is an uptake in the application of NGS in HIV drug resistance studies in Africa, albeit in a slower pace, with investigators from about a quarter of African countries applying the technology for this purpose.NR

An international comparative analysis of how South Africa can improve its turnover tax regime

A research report submitted in fulfillment of the requirements for the Master of Commerce, In the Faculty of Commerce, Law and Management, School of Accountancy, University of the Witwatersrand, Johannesburg, 2024This research report undertakes a comparative analysis aimed at outlining avenues for enhancing the turnover tax regime in South Africa. This analysis will outline existing shortcomings and furnish recommendations to the National Treasury for potential legislative amendments. By juxtaposing and analysing turnover tax systems operative in Australia, New Zealand, Singapore, and India, valuable insights can be collected to inform potential improvements to South African tax legislation, thereby fostering the advancement of microenterprises within the South African economy. Furthermore, this report aims to examine selected paragraphs of the Sixth Schedule of the Income Tax Act No. 58 of 1962, which governs the administration of microenterprises. It posits that a reassessment of these paragraphs holds the potential to accrue substantial benefits for microenterprises and fortify the overarching tax framework. Ultimately, by furnishing tax legislative recommendations geared towards improving the turnover tax system, this research report seeks to contribute significantly to the sustainability of both the small, medium, and microenterprises (SMME) sector and the broader South African economy.MM202

Sustainability of vegetable production systems by small-scale farmers of Limpopo Province in South Africa

Thesis (Ph.D.(Sustainable Agriculture))--University of the Free State, 2023The study was conducted in 23 villages of Limpopo Province through an article-based format. The study in area A, was conducted in six villages, four in Makhado Municipality of Vhembe District, and two villages in Greater Letaba Municipality in Mopani District. The objective of the study was to characterise vegetable production systems of small-scale farmers in the study area. Data was collected using a questionnaire and some information was gathered through direct observation. Fifty-two farmers were sampled using a multi-stage random sampling technique and were interviewed. The sample size was calculated using Lovin’s formula. Data was analysed using a SPSS. The results of the study showed that 59.62% of the farmers were males, 57.69% were above 61 years of age. The education status of women was lower than that of men and more women had no formal qualification. The 92.31% owned land and 80% of the plots ranged between 0.5 and two hectares. The 84.62% had vegetable farming experience ranging between 5 and 16 years. Water management system was characterised by some farmers (50%) who adapted to water shortage by planting drought tolerant vegetables, some19.23% used drip irrigation system and others (13.46%) used conservation tillage. The majority (71.15%) of these farmers used furrow irrigation and gravitational canal, and their main source of water was the river. They drew water using gravitation and pipes as well as gravitation and canals. Water availability ranged from daily to monthly. Human resource management was characterised by 48.08% of the vegetable farmers who employed a mixture of youth, male and female workers and 60% of the farmers hired workers on seasonal basis. Soil sampling did not exist because 65.54% did not take soil samples and 67.31% did not know when last they took soil samples, 65.38% used both organic and inorganic fertilisers. About 81% applied between 10-200kg fertiliser per hectare using band placing method. Other vegetable production practices identified include chemical pest control (100%); soil resource management was done through conventional tillage (86.64%); contours to control erosion (71.18%). Weed control was mainly manual (73.08%). Income generated from sale of vegetables was mainly used for labour, production inputs and mechanisation. Farmers in the study area kept records for finance, input, planting dates and yields. Most farmers used 0-10% of vegetables they produce for home consumption. The results of the study showed that vegetable production can be sustainable if water, soil, pests and disease are managed appropriately. The study in area B, was conducted in six villages situated in the four municipalities within the two districts of the Limpopo Province in South Africa. The study investigated vegetable production systems and consumption patterns as determinants of food security amongst small-scale vegetable farmers. A multi-stage random sampling technique was used to select 52 respondents for this study. The sample size was calculated using Slovin’s formula. Data was collected through a questionnaire and other information through direct observation. Data was analysed using the statistical package for social sciences. The study revealed that 65.38% of the participants were males 42.31% had an average age of 51-61 years and had 5-10 years farming experience. The study shows that male respondents 63.46% had secondary education and are more than females, and 71.16% had dependants ranging from five to above nine per household. The majority 92.31% own land for vegetable cultivation and more respondents who own land are males while 65.38% cultivating vegetables on land size ranging from 1-2 hectares. Most farmers (71.15%) cultivated a variety of vegetables; 90.38% grew vegetables in order to generate income; 38.46% grow vegetables because the market for vegetables is available. The study also revealed that 44.23% used drying method to preserve vegetable seeds; 90.38% used single cropping system for vegetables, and they practiced intensive vegetable production system. Vegetable preparation for food is characterised by 71% who use boiling as a cooking method while 55.77% used tomato and onion to enhance vegetable flavour and used salt to enhance vegetable taste. The study noted that 48.07% experienced pest infestation and high inputs costs as the main constraints in vegetable production. Vegetable consumption is characterised by 40.38% who consumed vegetables once per week; the 51.92% preferred to eat leafy vegetables than other vegetables. Most of the respondents (55.77%) were encouraged to eat vegetables that were appropriately cooked. The study also noted that adult women (38.46%) consume vegetable in the family, and they consumed 50-100g of vegetable per day. The study shows that 57.69% preserved vegetables by drying, because it is the cheapest method. The results of the study show that a variety of vegetables produced, and preservation are the main determinants of food security in the study area. The study in area C, was conducted in four villages, three from Thulamela municipality and one in Maruleng municipality. The objective of the study was to analyse climate change mitigation strategies adopted by small-scale farmers towards a sustainable vegetable production and resilient from food shortages in Limpopo Province. A multi-stage random sampling technique was used to select 52 respondents for this study. The size of the sample was calculated using Lovin’s formula. Data was collected through a structured questionnaire and direct observations. Data was analysed using the statistical package for social sciences. Results of the study revealed that more (53.85%) women participate in vegetable production. The study also shows that 59.62% had an average of 51-61 and above 61years of age. The 61.54% had secondary education. The 90.38% had no qualification in agriculture. The majority (67.31%) cultivate their crops on 1-2ha. The 81.76% have moderate ability to high ability to adapt to climate change. The majority of the respondents (88.46%) rate decrease in quality of irrigation water, decrease in soil fertility and increased soil erosion as factors that lead to land degradation due to climate change. The 86.54% view drought, high temperatures and more pests as rare events as a result of climate change. The 61.54% experienced a slight decrease in summer rainfall patterns. The adaptation to change in summer rainfall is mitigated by planting drought resistance vegetable crops and irrigating frequently to adapt to that change. The 61.54% experienced increased pest infestation due to climate change and they noticed an increase in the use of pesticides to adapt. An increase in winter temperature was noticed by 80.77% of farmers and 67.32% adapt by growing cool season vegetables. Changes in summer temperatures was noticed by 90.30% who experienced an increase in summer temperatures due to climate change. The respondents are aware that local authorities are concerned about climate change and other activities such as soil mining, veld fires and tree cutting that may be contributing to climate change. Strategies in response to climate changes include knowing about the importance of weather and climate change forecasts. The 57.69% say forecasting helps them to plan planting dates, others say it helps them to make a choice of vegetable varieties and to project rainfall distribution. The majority (84.62%) use Radio and TV as their main source of information about weather and climate. Farmers in the study area apply Climate-smart agriculture technologies including crop rotation by 71.15%, others use mixed cropping, mulching, no till, crop residue, contours to counter the impact of climate change. They also use climate smart agriculture for increased productivity, 51.92% use hybrid seeds, pesticides and fertilisers. The CSA soil fertility technologies are the use of manure (52%), others use crop residue and mulching. Types of fertilisers used, 63.46% use both organic and inorganic fertilisers. Water saving technologies feature 50% who use water harvesting technology as a way of saving water, few use mulching for soils to retain moisture longer. The results of the study show that 59.62% of the respondents use ridges/terraces to control soil erosion, and others use contour planting, other use grass strips. Risks posed by climate change are identified amongst others as reduced crop yield reduced, amount of rain, floods and rise in temperatures. The 63.46% minimise risks by using crop diversification and use hybrid seeds. The study shows that farmers in the study area are aware of the climate change and the related factors. They are also applying CSA technologies as mitigation strategies to ensure sustainable food supply. However, there is a need to support small-scale farmers with improved technologies for them to be able to mitigate and cope with climate change challenges. The study in area D, was conducted in five villages, the three villages in Vhembe District, and two villages in Mopani District. The objective of the study was to assess the potential of African Indigenous Vegetables (AIVs) towards the formation of a commercial, nutritional and sustainable production system. A total of 53 small-scale vegetable farmers were randomly sampled using a multi-stage cluster sampling procedure. Sample size was calculated using Slovin’s formula. Data was collected by means of a questionnaire and analysed using descriptive statistics. The study revealed that more women (64.15%) participated in the production of AIVs. The 54.72% of the respondents supplied AIVs all-year round. Some respondents (49.06%) grow AIVs for home consumption, while 64.15% are encouraged to grow AIVs because they are well adapted to the area, easy to grow and have short growing period. About 60% of the respondents indicated that AIVs are highly consumed by adults and pregnant women in the families. The study revealed that 90.57% of the respondents could harvest and sell 1-2 tons of AIVs per season. About 57% of the respondents benefited from all types of markets, local, farm stalls and high value markets. The study showed that 86.79% of the farmers in the study area received support from the Department of Agriculture and Rural Development, in the form of advice, and production inputs. The results of the study confirm that there is a potential for the formation of a nutritional and a commercial production system from AIVs in the study area because the market of AIVs is growing. The study in area E, was conducted in the eight villages, three of Vhembe District, and five villages of Mopani District. The objective of the study was to identify and analyse the opportunities and constraints of a wide adaptation to organic vegetable production systems by small-scale farmers. A total of 52 small-scale vegetable farmers were randomly sampled using a multi-stage cluster sampling procedures. Sample size was calculated using Slovin’s formula. Data was collected through a questionnaire and analysed using the SPSS. The female respondents (55.77%) participated in vegetable production. The study shows that 21.15% of women attended secondary-level education. The study shows that farmers in the study area have experience ranging from 11-21 yeas. The study also revealed that 61.54% of the respondents have access to land they own, lease and communal use. The study also showed that the respondents have dependents ranging from 1-above 9 in number. The study shows that farmers use fertilisers, crop rotation and practicing intercropping in order to promote soil fertility. The study shows that the respondents apply livestock manure, poultry manure and other types to boost their vegetables. It was also revealed that farmers are aware that pesticides are not healthy, and they use protective clothing, and wash their hands with soap after use. Weed is controlled manually. The respondents agreed that organic market has a potential of growth, while others say there is shortage of local organic markets. The study revealed that 80.77% of the respondents considered organic farming (OF) as more profitable, and 78.85% say that it saves on production costs. The study showed that 75.00% of the respondents believed that organic products fetch higher prices. About 53.85% had moderate knowledge of organic farming, while 65.38% were ready to receive technical skills on organic farming (OF). The study captured that 75% viewed conversion to organics as expensive while 44.23% were willing to convert to organic farming in the near future. The results of this study show that there are opportunities in farming on organic vegetables if the constraints and difficulties identified in the study area are dealt with. It is concluded that vegetable production in the study area is sustainable but can improve further by exploiting the opportunities presented by this sector, however, needs support where the needs and necessities are identified, so that it continues contributing in feeding the nation and generating income for the livelihoods of the small-scale farmers