RESUMEN

Urban animal farming is becoming increasingly important in feeding the growing population of many sub-Saharan African cities. However, management of the animal manure generated is proving to be challenging due to space restrictions. Vermicomposting is one of the methods proposed to address this challenge. This study investigated the environmental performance of the vermicompost system by measuring the gaseous emissions generated from the system. In addition, the vermicompost system was compared with other manure management systems currently in use, using life cycle assessment (LCA) methodology. The emissions factors for the vermicompost system were found to be 10.8, 62.3 and 12.8 g/Megagram biowaste for methane, nitrous oxide and ammonia, respectively. LCA showed satisfactory performance of vermicomposting in terms of global warming and eutrophication potential, although if the vermicompost generated is dumped, this could lead to increased eutrophication. However, this is still much lower than the eutrophication caused by open dumping of untreated manure.

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RESUMEN

During the past decades, land use change in the Lake Victoria basin has significantly increased the sediment fluxes to the lake. These sediments as well as their associated nutrients and pollutants affect the food and water security of millions of people in one of Africa's most densely populated regions. Adequate catchment management strategies, based on a thorough understanding of the factors controlling runoff and sediment discharge are therefore crucial. Nonetheless, studies on the magnitude and dynamics of runoff and sediment discharge are very scarce for the Lake Victoria basin and the African Rift region. We therefore conducted runoff discharge and sediment export measurements in the Upper Rwizi, a catchment in Southwest Uganda, which is representative for the Lake Victoria basin. Land use in this catchment is characterized by grazing area on the high plateaus, banana cropping on the slopes and Cyperus papyrus L. wetlands in the valley bottoms. Due to an increasing population pressure, these papyrus wetlands are currently encroached and transformed into pasture and cropland. Seven subcatchments (358 km2-2120 km2), with different degrees of wetland encroachment, were monitored during the hydrological year June 2009-May 2010. Our results indicate that, due to their strong buffering capacity, papyrus wetlands have a first-order control on runoff and sediment discharge. Subcatchments with intact wetlands have a slower rainfall-runoff response, smaller peak runoff discharges, lower rainfall-runoff ratios and significantly smaller suspended sediment concentrations. This is also reflected in the measured annual area-specific suspended sediment yields (SYs): subcatchments with encroached papyrus swamps have SY values that are about three times larger compared to catchments with intact papyrus vegetation (respectively 106-137 ton km(-2) y(-1) versus 34-37 ton km(-2) y(-1)). We therefore argue that protecting and (where possible) rehabilitating these papyrus wetlands should be a corner stone of catchment management strategies in the Lake Victoria basin.

RESUMEN

Traditional livestock healers from Samburu and Turkana communities in Samburu District of Kenya were identified and recruited for participation in this study. Sheep with mixed gastrointestinal helminthosis were purchased from nomadic livestock owners in the area. Three herbal anthelmintic remedies, viz. Myrsine africana, Albizia anthelmintica and Hilderbrantia sepalosa were administered in the traditional way by the healers and their efficacy determined using percent fecal egg count reduction (percent FECR) test. The results indicate that all the herbal remedies had some efficacy against both nematodes and Monezia species of helminths. The group effect against nematodes was significantly different (P=0.002). Compared to an untreated control group, the efficacy against nematodes was 77, 89.8 and 90% for Myrsine afriacana, Albizia antihelmintica and Hilderbrantia sepalosa, respectively, while albendazole had 100% efficacy. The main nematodes encountered included Haemonchus spp., Trichostrogylus spp. and Oesophagostomum spp. With regard to Monezia species herbal remedies performed better than albendazole with an efficacy of 100% compared to 63% for albendazole. The group of sheep treated with Albizia anthelmintica showed a significant increase (P=0.003) in packed cell volume (PCV).

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