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sur le développement des zones arides et semi-arides

Titre : Influence of Grazing Management Practices and Topographic Positions on Vegetation Attributes, Soil Organic Carbon and Greenhouse Gas Emissions in Semi-arid Rangelands of Laikipia County, Kenya

Auteur : Gitau, Angela N

Université de soutenance : University of Nairobi

Grade : Master of Science in Land and Water Management 2020

Résumé partiel
Semi-arid rangelands of Kenya have been managed through grazing for many years. This has influenced the landscape in terms of vegetation attributes such as species diversity, richness, composition, and abundance. Furthermore, a few studies have been done on how different land cover types under different grazing management practices as well as topographical positions influence soil organic carbon fraction content in the soil. Also, the aspect of greenhouse gas emissions under different land cover types and grazing management influence is poorly understood for semi-arid rangelands. The effect of grazing management practices on vegetation attributes, soil organic carbon fractions, and greenhouse gases was assessed for semi-arid rangelands of Laikipia County, Kenya. An experiment with a complete randomized design was set up to determine ; (1) the effect of grazing practices and topographic positions on vegetation attributes, (2) effect of grazing practices, topographic positions, and land cover on soil mineral-associated carbon (MAOC) and particulate organic carbon (POC) and (3) effect of grazing management practices and land cover types on CO2, CH4 and N2O emissions. The treatments were grazing management practices, continuous grazing and controlled grazing ; and the topographic positions ; mid-slope, foot slope, and bottomland. The land cover types, bare ground, patches of grasses, and mosaics of trees, were selected randomly and replicated three times. Both grazing practices and topographical positions had a significant (p<0.05) effect on the relative abundance of trees as well as grasses while it was highly significant (p<0.001) on herbs and forbs.

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