Abstract: Variations in weather and climate have a significant impact on rain-fed banana yields in East Africa. This study examined empirical linkages between banana yields and variations in rainfall and temperature over Uganda for the historical period (1971-2009) using time series moments, correlation and regression analysis. The Food and Agriculture Organization (FAO) Crop Water Assessment Tool (CROPWAT) was used to estimate banana crop water requirements, soil moisture deficits and their effects on banana yield levels under rain-fed conditions for different regions. The study observed high comparability in moment indices with some significant differences reflected in the values of the banana yields and rainfall and temperature moment indices. The cumulative effect of rainfall and temperature variations on banana yields was discernible from strong correlation coefficients of up to 78%. The CROPWAT simulations indicated up to 46% reductions in optimal banana yields due to soil moisture deficits within banana plantations. In conclusion, the study observed stronger linkages between banana yields and temperature variations than rainfall. In addition, temperature manifests both direct and indirect effects on banana growth while rainfall exhibits comparatively high intra-seasonal and intra-annual variability with lag effects on banana yields. The study provides a strong scientific basis for the development of coping, adaptation and mitigation strategies in the banana farming subsector in the region due to the anticipated shifts in rainfall and temperature extremes and changes across Uganda and neighbouring regions.
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Publication Date: 2013
Abstract: Impacts of Climate change and the associated vulnerabilities have increasingly become significant environmental issues of concern across the globe. Climate change is one of the greatest impediments to the realization of the first Millennium Development Goal of reducing poverty and food insecurity globally since it directly influences agricultural production and community livelihoods. Africa is highly vulnerable and especially the arid and semi arid lands which have low adaptive capacities. Approximately 80% of the African population is dependent on agriculture which it is currently facing myriad of challenges ranging from climate change to technology adoption. The sector therefore needs better support from policy makers, service providers and/or development agencies to remain the engine for economic growth and rural development. Analysis of climate trends in relation to regional production sectors such as crops using available scientific tools would create opportunities to incorporate relevant adaptation measures from the planning stages. This study found that the return periods for extreme climatic events such as drought as decreased from approximately 4 to 5 years before the year 2000 to about 2 years or less at present in the lower Tana River basin. Maize production in the region remains climatically undermined and farmers need to upscale the production of mangoes and cassava which grows and have good yields in the region. There is need to maximize the production opportunities of better yielding crops and encourage cross border trades in the country. Keywords: Climate change; Climate variability; Crop yields; Tana River basin.
Publication Date: 2013
Abstract: The changing climatic patterns and increasing human population within the Lake Victoria Basin (LVB), together with overexploitation of water for economic activities call for assessment of water management for the entire basin. This study focused on the analysis of a combination of available in-situ climate data, Gravity and Climate Experiment (GRACE), Tropical
Rainfall Measuring Mission (TRMM) observations, and high resolution Regional Climate simulations during recent decade(s) to assess the water storage changes within LVB that may be linked to recent climatic variability/changes and anomalies. We employed trend analysis, principal component analysis
(PCA), and temporal/spatial correlations to explore the associations and co-variability among LVB stored water, rainfall variability, and large scale forcings associated with El-Ni˜no/Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD). Potential economic impacts of human and climate-induced changes in LVB stored water are also explored. Overall observed in-situ rainfall from lake-shore stations showed a modest increasing trend during the recent decades. The dominant patterns of rainfall data from the TRMM satellite estimates suggest that the spatial and temporal distribution of precipitation have not changed much during the period of 1998-2012 over the basin consistent with in-situ observations. However,
GRACE-derived water storage changes over LVB indicate an average decline of 38.2 mm/yr for 2003-2006, likely due to the extension of the Owen Fall/Nalubale dam, and an increase of 4.5 mm/yr over 2007-2013, likely due to two massive rainfalls in 2006-2007 and 2010-2011. The temporal correlations between rainfall and ENSO/IOD indices during the study period, based on TRMM and model simulations, suggest significant influence of large scale forcing on LVB rainfall, and thus stored water. The contributions of ENSO and IOD on the amplitude of TRMM-rainfall and GRACE-derived water storage changes, for the period of 2003-2013, are estimated to be ∼ 2.5 cm and 1.5 cm, respectively.