Browsing by Author "Karanja, Rebecca"

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    Annual Diversity of Honey Bee pollen Sources in Two Pumpkin Growing Landscapes, Machakos County, Kenya
    (Journal of Pollination Ecology, 2025-03) Nang’oni, Marystella W.; Kasina, Muo; Karanja, Rebecca; Guantai, Mary M.; Kinyanjui, Rahab N.; Omuse, Evanson R.; Lattorf, H. Michael G.; Abdel-Rahman, Elfatih M.; Adan, Marian; Mohamed, Samira A.; Dubois, Thomas
    Multi-floral foraging sources for honey bee (Apis mellifera L.) have been threatened by landscape changes and unsustainable farming practices. In East Africa, the biodiversity of forage resources that could support honey bees, especially in agricultural lands, remains least explored. This study investigated pollen diversity for honey bees in Yatta and Masinga Sub-counties in Machakos County, Kenya. Honey bee hives were installed on eight pumpkin (Cucurbita maxima Duchesne ex Lam) farms (one hive per farm) in two varying landscape vegetation classes (low and medium) based on normalized difference vegetation index (NDVI). Pollen traps were installed at the hive entrance and pollen pellets were retrieved fortnightly for subsequent identification. Approximately 115 pollen types were identified. The pollen pellets were associated with 63 plant families and 109 plant families in low and medium NDVI classes, respectively. The predominant source of pollen for honey bees in low NDVI class included the plant families Poaceae (5,526 pellets), Asteraceae (3,176 pellets), Combretaceae (1,327 pellets), Acanthaceae (1,122 pellets), Amaranthaceae (960 pellets), Boraginaceae (951 pellets), Typhaceae (889 pellets), Guaduelleae (809 pellets) and Loranthaceae (588 pellets). In medium NDVI, most pollen was sourced from plant family Asteraceae (3,605 pellets), Malvaceae (1,572 pellets), Poaceae (1,538 pellets), Combretaceae (1,468 pellets), Salvadoraceae (1,354 pellets), Solanaceae (1,011 pellets), Asphodelaceae (885 pellets), Fabaceae (882 pellets), Euphorbiaceae (685 pellets) and Myrtaceae (546 pellets). The diversity of pollen types varied between the NDVI classes and across months. Although honey bees sourced diverse pollen required for the dietary balance of the colony, there was variability across landscape types and months.
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    Impacts of selected Climate Smart Agricultural Practices on African Indigenous Vegetables in Kenyan drylands
    (African Phytosanitary Journal, 2024) Muthama, Eric; Najma, Dharani; Samita, Namikoye; Karanja, Rebecca
    Climate change has had significant impacts on the cultivation of African Indigenous Vegetables (AIVs) resulting in insufficient yields and food insecurity. African indigenous vegetables are important food crops used in combating malnutrition and food insecurity. The AIVs have the potential to provide nutrition and sustain smallholder farmers’ livelihoods. However, little is known about the impacts of ClimateSmart Agriculture Practices (CSAPs) on the yield levels in AIVs. This study was therefore conducted to evaluate the impacts of selected CSAPs on the yield levels in cowpeas (Vigna unguiculata. L) and black nightshade (Solanum nigrum. L) in Kenyan drylands. Six treatments consisting of organic manure, commercial organic fertilizers, irrigation, mulching, inorganic fertilizers and controls were used. Research plots measuring 3m by 3m were set out in a randomized complete block design and sowed with certified cowpeas seeds and well-established black nightshade seedlings. Treatments were applied at land preparation and at 7 days after crop germination. Data was collected on plant height at vegetative stage and the overall primary yield at crop maturity. Analysis of variance (ANOVA) was conducted on the quantitative data collected and analyzed using Genstat software. Post hoc analysis was carried out for significant means using Tukey’s Honest Significant Difference (HSD) test at p≤0.05. The results revealed significant differences in both the plant height and primary yield across all treatments (p≤0.05). The AIV yield levels were significantly influenced by the CSAPs products used. Plots treated with organic manure, mulching and commercial organic fertilizers had significantly higher yields. Control plots had the least amount of yields.