Browsing by Author "Mathema, Ndabanye"

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    Allellopathy as trait of invasiveness of Sorghum halepense L. (Pers) on germination and establishment of weedy grass species (Rotteboellia cochinchinensis, Eleusine indica (L) and Ipomoea purpurea)
    (Academic Journals, 2025-04) Polite, Masara; Zivanayi, Musabayana; Lenon, Tembo; Mathema, Ndabanye
    Biology of alien plants contributes to invasiveness of both natural and agrarian ecosystems. Bio-assay experiments were set up at Bindura University of Science Education, Zimbabwe, to evaluate allelopathy as traits of invasiveness of Sorghum halepense L. (Pers) on germination and establishment of grass species. The results indicated that germination rate, growth rate and dry matter accumulation was highly affected by S. halepense extracts. Seed germination was improved by dormancy-breaking treatments, with the highest germination rate attained using a combination of sulphuric acid and potassium nitrate. Equally, the lowest germination rate was observed in seeds treated with water and a 2% sodium hypochlorite solution. The greatest seedling growth was observed in seeds treated with sulphuric acid and potassium nitrate whereas the lowest growth rate was recorded in seeds treated using sodium hypochlorite. S. halepense extracts affected dry matter accumulation of all grass species tested. Rottboellia species had the highest seed germination rate of 90%, followed by Eleusine 88%, and Ipomoea species 66% being the least. The highest germination inhibition was observed in leaves when compared to extracts from stems, roots and flowers. In pot experiments, S. halepense leaves affected growth and dry matter accumulation. Results showed that S. halepense extracts affect germination and establishment of grass species.
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    Efficacy of Lippia Javanica Leaf Powder and Combretum Imberbe Wood Ash Against the Larger Grain Borer (Prostephanus Truncatus) in Stored Maize
    (Taylor & Francis, 2026-06-26) Chihumbiri, Lorraine Yeukai; Musabayana, Zivanayi; Zhou, Mandhlenkosi; Mathema, Ndabanye; Tembo, Lenon; Zanamwe, Pesanai
    Prostephanus truncatus is a major storage pest responsible for substantial maize grain losses. This study evaluated the efficacy of Lippia javanica leaf powder and Combretum imberbe wood ash in controlling P. truncatus in stored maize. The study consisted of two separate trials, each with six treatments, replicated thrice and arranged in a Completely Randomized Design (CRD). The treatments for the first trial consisted of four dosages of L. javanica (2, 4, 6, 8 g) applied to 200 g of maize grain, the untreated control and Actellic Gold Dust. The second trial treatments consisted of four dosages of C. imberbe (2, 4, 6, 8 g) applied to 200 g of maize grain, an untreated control and Actellic Gold Dust. Each experimental unit was infested with 10 adult Prostephanus truncatus, and assessments were conducted at 7, 14, and 21 days after treatment. The efficacy of L. javanica leaf powder and C. imberbe in the control of P. truncatus was assessed by determining insect mortality, insect reproduction, mean grain weight loss, and mean grain damage. Both biopesticides significantly (p < 0.05) increased adult insect mortality and suppressed reproduction compared to the untreated control. The highest mortality (90%) was observed at 8 g for both botanicals and reproduction was reduced by 5–85% relative to the control for L. javanica and 10–92% for C. imberbe, depending on dosage. The findings demonstrate that L. javanica and C. imberbe are promising bioinsecticides for maize protection against P. truncatusa especially for smallholder farmers.
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    Growth and Yield Yesponse of Cabbage (Brassica Oleracea Var.Capitata ‘Star 3011’) to Different Liquid Organic Manure Types and Their Combinations
    (Taylor & Francis, 2026-04-26) Zhou, Mandhlenkosi; Musabayana, Zivanayi; Tembo, Lenon; Mathema, Ndabanye; Zanamwe, Pesanai
    The application of organic liquid manures is deemed a viable alternative to the application of inorganic fertilisers in vegetable production. this study was carried out to evaluate the effect of different types of liquid manure and their combinations on the growth and yield of cabbage, cultivar Star 3301. the study was conducted during the2020–2021 and 2021–2022 seasons at the Tshaka Maoko Organic Nutrition Garden in Chiredzi, Zimbabwe. the experiment was arranged in a randomised complete block design with nine liquid manure treatments, namely, cattle, poultry, green groundnut, combinations of cattle-poultry, cattle-green groundnut, poultry-green groundnut, cattle-poultry-green groundnut, a negative control and a positive control. liquid manure types and their combinations significantly affected cabbage growth and yield attributes, including days to heading, days to horticultural maturity, head diameter and head weight. the negative control showed the lowest values in all the attributes measured. The combination of cattle-poultry-green groundnut liquid manure showed the best performance and was comparable to the positive control and the poultry-green groundnut liquid manure. Crops treated with these treatments took a short time to form heads and to reach maturity and had heavy and large heads. The single liquid manure treatments showed intermediate performance. Among the single liquid manures, cattle liquid manure was the least effective. It was concluded that combining organic liquid manure, such as a combination of extracts from cattle, poultry and green groundnut, could be used as an alternative to inorganic fertilisers in cabbage production.
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    Poor maize productivity in Zimbabwe: Can collusion in pricing by seed houses be the cause?
    (Cogent OA, part of Taylor & Francis Group, 2019-11-04) Tibugari, Handsen; Chikasha, Tinei; Manyeruke, Ngonidzaishe; Mathema, Ndabanye; Musara, Joseph P.; Dlamini, Dumisa; Mapuranga, Rangarirai; Mapanje, Olga; Banda, Annabel; Parwada, Cosmas
    High cost of hybrid seed can affect food self-sufficiency. A study was conducted to investigate the structure, conduct and performance of the hybrid maize seed industry in Zimbabwe to determine whether the level of competition in the industry caused high and unstable prices. Primary data on the quantity of hybrid maize produced and/or marketed, pricing strategies and hybrid maize seed prices for the period 2011 to 2015 was collected using questionnaires administered to marketing managers of 10 seed houses involved in hybrid maize seed production and marketing in Zimbabwe as well as key stakeholders. The questionnaires were also used as interview guides for key informant interviews with production managers of respective seed houses. Secondary data were obtained from annual reports and technical bulletins of respective companies. The analysis involved respondent triangulation as well as triangulating the data from responses with secondary data in order to increase the convergent validity of the data. Descriptive statistics, ANOVA and trend analysis were used for data analysis. Results indicated that the hybrid maize seed industry in Zimbabwe is highly concentrated meaning that there is low competition. The study established that there may be tacit collusion in the pricing of hybrid maize seed in the form of dominant firm price leadership. The study showed that prices have not been stable for the period 2011 to 2015. It is recommended that the government should enact policies that; prohibit abuse of a dominant position, prohibit mergers which create or strengthen a dominant position and prohibit state aid that creates monopolies.
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    Worrying cadmium and lead levels in a commonly cultivated vegetable irrigated with river water in Zimbabwe
    (Cogent OA, part of Taylor & Francis Group, 2020-08-10) Tibugari, Handsen; Mafere, Gerald; Dube, Sinikiwe; Chakavarika, Murawu; Mandumbu, Ronald; Musara, Joseph P.; Mapuranga, Rangarirai; Gumbo, Tapiwa; Banda, Annabel; Mathema, Ndabanye; Goche, Tatenda; Zvigumbu, Bernard M.; Mpofu, Nkosentsha
    Vegetable cultivation using river water, which may be polluted with heavy metals, can cause health problems to consumers. A study to establish cadmium and lead levels in water from Msasa, Manyame; Mukuvisi and Nyatsime Rivers was conducted in 2019. A questionnaire survey involving 105 randomly selected urban vegetable growers was conducted to examine farmer knowledge of the potential of polluted water to contaminate produce through heavy metals. Water, soil and vegetable samples were also collected and analysed for heavy metal presence using atomic absorption spectrophotometry. Results showed that some farmers (62%) were aware that wastewater could contain heavy metals. The majority of farmers (67%) applied phosphate-based fertilisers, a potential source of cadmium. Tested at P < 0.05, the results showed that sampled water from the four sites failed to meet the Standards Association of Zimbabwe 5560 (1997) standards. Cadmium tissue concentration from wastewater from Msasa and Manyame rivers was 1.3 and 1.17 mg g−1 respectively, which were 59 and 65 times higher than 0.02 mg g−1 from the control. Water from Manyame and Nyatsime rivers contains levels of heavy metals which exceed the Environmental Management Agency (EMA) safety guidelines. Farmers need to be educated on health hazards from contaminated wastewater. Enforcing regulations on effluent disposal, licencing of vegetable vendors and labelling of vegetables with information on source of water used to irrigate the crop can help reduce exposure of unsuspecting vegetable consumers.