Adoption Potential of Conservation Agriculture Practices in Sub-Saharan Africa: Results from Five Case Studies

Despite the reported benefits of conservation agriculture (CA), its wider up-scaling in Sub-Saharan Africa (SSA) has remained fairly limited. This paper shows how a newly developed qualitative expert assessment approach for CA adoption (QAToCA) was applied to determine its adoption potential in SSA. CA adoption potential is not a predictor of observed adoption rates. Instead, our aim was to systematically check relevant factors that may be influencing its adoption. QAToCA delivers an assessment of how suitable conditions “and thus the likelihood for CA adoption” are. Results show that the high CA adoption potentials exhibited by the Malawi and Zambia case relate mostly to positive institutional factors. On the other hand, the low adoption potential of the Zimbabwe case, in spite of observed higher estimates, is attributed mainly to unstable and less secured market conditions for CA. In the case of Southern Burkina Faso, the potential for CA adoption is determined to be high, and this assessment deviates from lower observed figures. This is attributed mainly to strong competition of CA and livestock for residues in this region. Lastly, the high adoption potential found in Northern Burkina Faso is explained mainly by the fact that farmers here have no alternative other than to adopt the locally adapted CA system—Zaï farming. Results of this assessment should help promoters of CA in the given regions to reflect on their activities and to eventually adjust or redesign them based on a more explicit understanding of where problems and opportunities are found.     

An approach to simulate wind fields around an urban environment for wind energy application

This work proposes an approach to simulate wind flow fields around an urban environment with the aim of evaluating the potential impact of buildings on the general wind patterns and power production using the current generation of commercial wind turbines. The simulation process was performed with the aid of accessible computational tools that can potentially render the proposed procedure applicable in other cases of interest. The roughness of the urban environment was defined as the association of roughness map, topography, and an alternative process for obtaining the volumetry of buildings. A case study was conducted in a region located at the district of Boa Viagem (Recife-PE) for assessing the applicability of the approach. Scenarios were designed in order to simulate wind flow patterns and pre-identify sites that have suitable wind energy potential for electric power production by investigating the combination of wind speed magnitude and turbulence intensity. From the results obtained, it was possible to identify zones of potential wind sources that are not detected in classical wind atlas probably due to the influence of the built environment on local wind flow patterns.     

Delonix regia and Casuarina equisetifolia as passive biomonitors and as bioaccumulators of atmospheric trace metals

The suitability of two common and ubiquitously distributed and exotic ornamental plant species in Nigeria-Delonix regia and Casuarina equisetifolia as biomonitors and as effective bioaccumulators of atmospheric trace metals(Cd,Pb,Zn and Cu) has been evaluated.Bark and leaf samples from these plant species were collected in June and July 2006 at five locations in Benin City.Four of the sampling sites were in areas of high traffic density and commercial activities,the fifth site is a remote site,selected to act as a control and also to provide background information for the metals.The plant samples were collected and processed using standard procedures and trace metals were determined using atomic absorption spectrometer.The bark of the plants was able to bioaccumulate the trace metals,especially Pb which originates from anthropogenic contributions in the city.The Pb range of 20.00-70.00 μg/g measured for the bark samples of D.regia,exceeded the normal plant Pb concentration of 0.2-20.0 μg/g and most Pb data available in literature.The bark of the plants was observed to accumulate more metals compared to the leave,while D.regia was found to be slightly better than C.equisetifolia in trace metal uptake efficiency.Spatial variations in the distributions of Pb and Zn were significant(p 0.05),and the continuous use of leaded fuel in Nigeria was identified as the predominant source of Pb in the atmosphere.