Suitability of treated wastewater with respect to pH, electrical conductivity, selected cations and sodium adsorption ratio for irrigation in a semi-arid region

Increasing incidents of drought spells in most Sub-Saharan African countries call for exploration of innovative alternative sources of water for irrigation. A study was conducted to investigate the cation concentrations for different disposal points of treated wastewater and for borehole water. A 4 × 5 factorial experiment included a borehole as a reference sampling site plus three other sampling sites along the wastewater disposal system over 5 months. Monthly collected water samples were analysed for pH, EC, Ca, Mg, Na and K, with sodium adsorption ratio (SAR) computed and compared with those of water from the borehole, the FAO-desired ranges and the South African (SA) quality standards for irrigation water. Except at two sampling sites during one month, pH values were within the FAO-desired range. Relative to the FAO desired ranges and SA water quality standards, most variables in treated wastewater were much lower, suggesting that the test treated wastewater was suitable for irrigation.Keywords: cation content, temporal effects, treated wastewater disposal, water scarcit

Medicinal plant cultivation for sustainable use and commercialisation of high-value crops

Many traditional healing systems are based on natural biological resources, and there is a general shift in most parts of the world towards natural medicine, with direct implications on the demand and supply of medicinal plants. This review highlights the economic importance of medicinal plants, their contribution to healthcare systems, and potential opportunities for rural economic development through cultivation.  A systematic literature review with specific search terms related to medicinal plants was used to collect scientific and non-scientific information from peer-reviewed literature and grey literature databases. The findings indicate that trade in medicinal plants is increasing, and although they are considered minor crops compared to major food crops, their value is among the highest in the list of traded plants globally. The trade also serves as a revenue source for many rural livelihoods, with women playing a significant role. Medicinal plants contribute to primary health care in many developing countries, and they are also an essential source of modern drug discovery. Cultivation of medicinal plants offers emerging rural farmers an opportunity to grow these plants as new and alternative crops, thus reducing unsustainable wild harvesting and competition with established commercial farmers who mostly focus on food crops. Furthermore, medicinal plant cultivation should be promoted as one of the options for local economic development and sustainability through job creation, the revival of the rural economy, and income generation for small businesses, such as the transport businesses, involved in the value chain. Land accessibility, financial resources, and direct market access for rural communities can elevate their contribution to the industry. Formalisation of the lower levels of the medicinal plant trade is also recommended. Significance:• Cultivation is a viable option for biodiversity conservation of medicinal plants and ensuring a goodquality supply of plant materials.• Cultivation of medicinal plants – a source of natural products used in product development – can contribute to job creation, income generation, and rural economies in developing countries.• This review underlines the importance of medicinal plants in product development, the contribution of the industry to economies of different countries, and the potential for cultivation

Morphological adjustment in free-living Steinernema feltiae infective juveniles to increasing concentration of Nemafric-BL phytonematicide.

Third-stage larvae (L3) of Steinernema feltiae exist as free-living infective juveniles (IJ), with suspended development activities. In contrast, parasitic stages (L1, L2, L4, adult) have mutualistic relations with Xenorhabdus species bacteria, along with unique morphological changes and development inside the cadaver of host insects and/or plant-parasitic nematodes. Commercial IJ strains are tolerant to cucurbitacin-containing phytonematicides, but we have scant information on how morphological adjustments in IJ are achieved. In this study, we investigated the nature of morphological adjustments in commercial S. feltiae IJ strains to Nemafric-BL phytonematicide, which contains cucurbitacin B as active ingredient. Post-72 h exposure to phytonematicide concentration, IJ specimens were fixed on mounting slides. Length (body, excretory pore to anterior end, pharynx, rectum, stoma, tail), diameter (head width, neck base, mid-body, anal body), cuticle thickness and De Man ratios were measured with a computer software programme attached to Omax light microscope. Morphometric data against increasing phytonematicide concentration exhibited either density-dependent quadratic, linear or neutral relations. Increase in body length at low phytonematicide concentration was accompanied by decrease in tail length and pharynx length during muscle contraction when IJ were still alive. After death at high phytonematicide concentration, the opposite morphometric effects ensued due to muscle relaxation. The observed changes in morphometric structures were explained on the basis of morphological adjustments that modulated volumes of pseudocoelom cavity in IJ. The modulation is intended to maintain hydrostatic pressure within permissible upper limits in order to avoid structural damage to internal organs embedded in the pseudocoelom fluids

Suitability of treated wastewater with respect to pH, electrical conductivity, selected cations and sodium adsorption ratio for irrigation in a semi-arid region

Increasing incidents of drought spells in most Sub-Saharan African countries call for exploration of innovative alternative sources of water for irrigation. A study was conducted to investigate the cation concentrations for different disposal points of treated wastewater and for borehole water. A 4 × 5 factorial experiment included a borehole as a reference sampling site plus three other sampling sites along the wastewater disposal system over 5 months. Monthly collected water samples were analysed for pH, EC, Ca, Mg, Na and K, with sodium adsorption ratio (SAR) computed and compared with those of water from the borehole, the FAO-desired ranges and the South African (SA) quality standards for irrigation water. Except at two sampling sites during one month, pH values were within the FAO-desired range. Relative to the FAO desired ranges and SA water quality standards, most variables in treated wastewater were much lower, suggesting that the test treated wastewater was suitable for irrigation

Seasonal variation of tannin content in wild bush tea

Please refer to abstract in articleNational Research Foundatio

Seasonal responses of total antioxidant contents in cultivated bush tea (Athrixia phylicoides L.) leaves to fertilizer rates

The objective of this study was to determine the seasonal effects of nitrogen (N), phosphorus (P) and potassium (K) fertilizer on total antioxidant content of cultivated bush tea (Athrixia phylicoides L.) leaves. Three independent trials of N, P and K were conducted per season i.e. autumn, winter, spring and summer. Treatments consisted of 0, 100, 200, 300, 400 or 500 kg/ha N, P or K replicated four times in a randomized complete block design. At harvest, leaves were freeze dried and ground for total antioxidant using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Results of this study demonstrate that regardless of season, the application of N, P and K fertilizers quadratically increased total antioxidant content, with most of the increase occurring at 0-300 N, 300 P and 100 K kg/ha. Therefore, for improved total antioxidant contents in cultivated bush tea leaves, 300 N, 300 P and 100 K kg/ha N is recommended.Morgenzon Nursery and the National Research Foundation (NRF

Seasonal variation of total antioxidant content of wild bush tea

The objective of this study was to determine the seasonal variation on the total antioxidant contents of wild bush tea leaves. At harvest, leaves were freeze dried and ground for total antioxidants using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) method. The results of this study demonstrated that the total antioxidants contents were lowest during autumn (66%) and spring (67%) whereas the highest were during winter and summer (99%). Thus, suggesting winter and summer as best time to maximize the potent antioxidant contents of wild bush tea leaves

Effects of nitrogen fertilization on tannin content of bush tea (Athrixia phylicoides L.) grown in different seasons

Bush tea, Athrixia phyliciodes L. (Asteraceae family) is a popular plant in South Africa used predominantly as an herbal tea and for medicinal purposes, including the cleansing or purifying blood and the treating of boils (carbuncles) and coughs. In some parts of South Africa, bush tea is used as an aphrodisiac. In this study, bush tea was grown under varying nitrogen (N) levels in four experiments that collectively covered a whole year to determine the seasonal nutrient requirements for improvement of quality. The treatments consisted of 0, 100, 200, 300, 400 and 500 kg·ha-1 N in a randomized complete block design, replicated four times (autumn, winter, spring, summer) under 50% shade nets. The tannins were extracted with acetone, mixed with reagent (butanol-HCL for condensed tannins and potassium iodate for hydrolysable tannins), and levels measured spectrophotometrically. The results of this study demonstrated that both condensed and hydrolysable tannins increased quadratically in response to N nutrition reaching a maximum at 300 kg·ha-1 N. Maximum content of condensed tannins was 4.5% which was achieved when growing the plants in during autumn and winter, whereas maximum content of hydrolysable tannins was 0.1%, achieved during spring and summer. Therefore, for improved condensed tannin content in bush tea leaves growing during the autumn (4.5%) or winter (3.7%) and hydrolysable tannins during spring and summer (0.1%), 300 kg·ha-1N is recommended

Genetic analysis among selected vernonia lines through seed oil content, fatty acids and RAPD DNA markers

Vernonia (Vernonia galamensis) is a new potential industrial oilseed crop. The seeds of this crop contain unusual naturally epoxidised fatty acids which are used in the production of various industrial products. The objective of this study was to evaluate and select vernonia lines in Limpopo province through seed oil content, fatty acid content and RAPD DNA markers. Significant differences were observed for the content of seed oil (22.4 - 29.05%), vernolic acid (73.09 - 76.83%), linoleic acid (13.02 - 14.05%), oleic acid (3.77 - 5.28%), palmitic acid (2.48 - 2.98%) and stearic acid (2.26 - 2.75%). Among the 13 RAPD DNA primers screened, primer OPA10 amplified DNA samples and resulted in 4 distinct groupings among tested lines. Four promising lines were selected; Vge-16, Vge-20, Vge-27 and Vge-32 using seed oil content, fatty acids and RAPD markers. The lines will be used for strategic breeding of vernonia as an alternative industrial oil crop in Limpopo province of South Africa or other similar environments