An improved technique for the prediction of optimal image resolution(s) for large-scale mapping of savannah ecosystems

Past studies to predict optimal image resolution required for generating spatial information for savannah ecosystems have yielded different outcomes, hence providing a knowledge gap that was investigated in the present study. The postulation, for the present study, was that by graphically solving two simultaneous equations of values of image noise index (INI) and degradation level Index (LDI), a robust technique for predicting optimal image resolution for the mapping of savannah ecosystems was developed. The technique involved simulating 0.5 m imagery to different spatial resolutions for two savannah test sites in Masaka district, Southern Uganda. By plotting INI and LDI values against the simulated image resolutions, it enabled the authors to objectively predict that image resolution at 2.25 and 2.5 m were optimal for generating spatial information for savannah ecosystems represented by the two test sites. The new technique will enable vegetation ecologists to objectively determine optimal resolution(s) prior to the choice of imagery, offered by different high-resolution air- and space-borne sensors, for generating spatial information for savannah ecosystems. Future research should focus on using the new technique to determine what ranges of image resolutions are optimal for generating spatial information of different savannah ecosystems in different countries.Key words: Optimal resolution, savannah ecosystems, image noise index, land cover index, level of degradation index

Lunnyu soils in the Lake Victoria basin of Uganda: Link to toposequence and soil type

We compared the physico-chemical characteristics of Lunnyu soils using soil type and slope position in order to explain their variability in the Lake Victoria basin of Uganda. Lunnyu patches located on four different soil types (chromic lixisol, mollic gleysols and plinthic ferralsols) were selected. At each patch, the slope was divided into shoulder, back-slope and foot-slope. Five locations along the contour of each landscape position and at distance of 20 to 30 m were located and soil samples taken at two depths (0 to 20 cm and 20 to 40 cm). The soils were analyzed for pH, available P, texture, and exchangeable bases. Lunnyu patches on chromic lixisol and mollic gleysols had higher pH, P, sand, clay and silt compared to those on plinthic ferralsols and petrifferic lixisol. Neither of the soil properties was influenced by landscape position. Soil pH, Ca, Mg, and K were higher in topsoil compared to subsoil. Neither slope position nor the type of lunnyu has showed consistent differences in all the soil properties. Results suggest a pedological explanation in which pH and texture could influence occurrence of the lunnyu soils. We recommend further studies of the pedological properties of the soils and other trace elements that this study has not investigated.Key words: Lunnyu soil, toposequence, soil type, Uganda

Dynamics of forest cover conversion in and around Bwindi impenetrable forest, Southwestern Uganda

Forest cover has been converted to agricultural land use in and around the protected areas of Uganda. The objectives of this study were; to examine the dynamics of forest cover change in and around Bwindi impenetrable forest between 1973 and 2010 and to identify the drivers of forest cover change. The trend in forest cover change was assessed by analyzing a series of orthorectified landsat imageries of 1973, 1987 and 2001 using unsupervised and supervised classification. Land use/cover map for 2010 was reconstructed by analyzing 2001 image, validated and/or reconstructed by ground truthing, use of secondary data and key informant interviews. A series of focused group discussions and key informant interviews were also used to identify drivers of land use/cover change. Policies and institutional arrangements that could have affected forest cover change for the studied time period were also identified. Results showed that protected forest and woodlot in unprotected area had declined by 7.8% and 70.7% respectively as small scale farming and tea plantations had increased by 13.9% and 78.3% respectively between 1973 and 2010. The conversions were attributed to land use pressure due to population growth, change in socio-economic conditions and institutional arrangements. The severe loss of woodlot outside the protected area not only poses a potential threat to the protected forest but also calls for intervention measures if efforts to mitigate climate change impacts are to be realized

Effect of topography on soil erodibility in Kakuuto micro-catchment, Uganda

No Abstract Available E. Afr. Agric. For. J. 2003 69(1), 19-2

Principles, design and processes of integrated agricultural research for development: experiences and lessons from LKPLS under the SSACP

With increasing recognition holding the promise of overcoming the outstanding problems faced by African agriculture, IAR4D faces the danger of being ‘blurred’ by past approaches and falling short of its potential to deliver the desired impacts in diverse multi-stakeholder, biophysical, socio-economic, cultural, technological and market contexts unless its actualisation and working is clearly understood. In this paper, we present the conceptualisation and principles of and knowledge-based experiences and lessons from the implementation of the sub-Saharan Africa Challenge Programme (SSACP) in the Lake Kivu Pilot Learning Site (LKPLS). The presentation covers the formation and facilitation of IPs for the actualisation of IAR4D to evolve mechanisms for the early recognition of interlinked issues in natural resource management, productivity and value addition technologies, markets, gender and policy arrangements. These have autonomously triggered flexible, locally directed interactions to innovate options from within or outside their environment for resolving the challenges, and have moved along a new institutional and technological change trajectory. Emerging lessons point to the endowment of IP members with selfhelp knowledge interactions, training in IAR4D, quality of facilitation and research to be key determinants of the power behind of self-regulating mechanisms

Integrated sustainable waste management in developing countries

This paper uses the lens of 'integrated sustainable waste management' to examine how cities in developing countries have been tackling their solid waste problems. The history of related concepts and terms is reviewed, and ISWM is clearly differentiated from integrated waste management, used mostly in the context of technological integration in developed countries. Instead, integrated sustainable waste management examines both the physical components (collection, disposal and recycling) and the governance aspects (inclusivity of users and service providers; financial sustainability; coherent, sound institutions underpinned by proactive policies). The data show that performance has improved significantly over the last 10 years. Levels of collection coverage and controlled disposal of 95% in middleincome and 50% in low-income cities are already commonplace. Recycling rates of 20-30% are achieved by the informal sector in many lower income countries, at no direct cost to the city - presenting a major opportunity for all key stakeholders if the persistent challenges can be resolved. The evidence suggests that efficient, effective and affordable systems are tailored to local needs and conditions, developed with direct involvement of service beneficiaries. Despite the remaining challenges, evidence of recent improvements suggests that sustainable solid waste and resources management is feasible for developing countries