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\hypersetup{pdftitle={Harnessing Wood Ash for Urban and Peri"=urban Agriculture},pdfauthor={Dora Neina},pdfsubject={Tropentag 2016: Abstract},pdfkeywords={CaCO3 equivalent, charcoal, fertiliser value, firewood, UPA vegetables},pdfpagemode=None,colorlinks=true}
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\parbox[b]{13.4cm}{\centering \large{\textbf{Tropentag, September 18-21, 2016, Vienna, Austria}}\\[1ex] \Large{``Solidarity in a competing world ---\\fair use of resources''\\[2ex]}}
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\Large{\textbf{Harnessing Wood Ash for Urban and Peri"=urban Agriculture\footnote{\textbf{Contact Address:} Dora Neina, University of Ghana, Soil Science, Department of Soil Science P. O. Box Lg 245 College of Applied and Basic Sciences University of Ghana, Accra, Ghana, \mbox{e-mail}: \email{dneina@gmail.com}}\\[0.8ex]}}
\normalsize{\textsc{Dora Neina}}
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\item[]{\small{\textit{University of Ghana, Soil Science, Ghana}}}
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\textbf{Abstract}
\begin{abstract}
\normalsize{
Firewood and charcoal are the prevalent sources of domestic energy in sub-Saharan Africa. About \mbox{90\,\%} of rural Ghanaian households use firewood for cooking while \mbox{61\,\%} of urban inhabitants prefer charcoal. Moreover, food vendors are widespread in urban areas and also depend on biomass energy for cooking. Wood ash (WA) is generated from biomass combustion and has 17--\mbox{95\,\%} of CaCO3 equivalent for neutralizing soil acidity. The actual composition of WA depends on the type and source of biomass and the type and temperature of combustion. Wood ash also contains substantial amounts of plant nutrients such as Ca, K, Mg, and P. Sadly, WA ends up in waste dumps, yet urban and peri"=urban agriculture (UPA) in Ghana battles with soil nutrient decline caused by continuous cultivation and nutrient export through harvests. Regrettably, no study has either compared the compositions of WA from firewood which is used in its ``natural form'', and charcoal which is produced through slow pyrolysis, or focused on WA utilisation in UPA. A previous study involving WA and human urine fertiliser amended to two Ghanaian Acrisols showed increases in soil pH by 1.2 units and a two"=fold increase in Ca, K, Mg, and Na contents after one and twelve weeks of application, respectively. This study attempts to answer the questions: Do the chemical compositions of WA from firewood and charcoal differ? How much WA is required to neutralize soil acidity and improve crop yield in UPA? Is the WA generated in urban areas enough to supplement nutrient supply in UPA? To unravel these puzzles, an initial study will quantify and characterise WA from firewood and charcoal from food vendors in five major Ghanaian cities. Further, a more detailed study will conduct laboratory and field experiments to (a) quantify the amount of WA required to reach suitable soil pH for common UPA vegetables in Ghana and  (b) grow such vegetables both in pots and on"=farm experiments involving WA to estimate yield and cost"=benefits. The outcome of this study is expected to contribute to knowledge on the composition, fertiliser value, and the potential use of WA in UPA systems. }

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\noindent \textbf{Keywords:} CaCO3 equivalent, charcoal, fertiliser value, firewood, UPA vegetables
\index[key]{CaCO3 equivalent}
\index[key]{Charcoal}
\index[key]{Fertilizer value}
\index[key]{Firewood}
\index[key]{UPA vegetables}
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