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\hypersetup{pdftitle={Biomass of Aquatic Weeds - Energetic Potencial in Tropical and Subtriopical Regions},pdfauthor={Vladimir Krepl, Patrick Francis Kapila, Martin Dvorak},pdfsubject={Tropentag 2010: Abstract},pdfkeywords={Aquatic plants,, Biomass, Eichhornia, Pistia, water weeds},pdfpagemode=None,colorlinks=true}
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\parbox[b]{13.4cm}{\centering \large{\textbf{Tropentag, September 14-16, 2010, Zurich}}\\[1ex] \Large{``World Food System  ---\\A Contribution from Europe''\\[2ex]}}
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\begin{center}
\Large{\textbf{Biomass of Aquatic Weeds - Energetic Potencial in Tropical and Subtriopical Regions\footnote{\textbf{Contact Address:} Martin Dvorak, Czech University of Life Sciences, Department of Sustainable Technologies, Kamycka 129, 165 21~Praha - Suchdol, Czech Republic, \mbox{e-mail}: \email{dvorakm@its.czu.cz}}\\[0.8ex]}}
\normalsize{\textsc{Vladimir Krepl$^{1}$, Patrick Francis Kapila$^{2}$, Martin Dvorak$^{3}$}}
\end{center}
\begin{itemize*}
\item[]{\small{\textit{$^{1}$Czech University of Life Sciences Prague, Institute of Tropics and Subtropics, Czech Republic}}}
\item[]{\small{\textit{$^{2}$University of Venda, South Africa, School of Agriculture, }}}
\item[]{\small{\textit{$^{3}$Czech University of Life Sciences, Department of Sustainable Technologies, Czech Republic}}}
\end{itemize*}
\index[author]{Krepl, Vladimir}
\index[author]{Kapila, Patrick Francis}
\index[author]{Dvorak, Martin}
\begin{center}
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\textbf{Abstract}
\begin{abstract}
\normalsize{
Invasive species of freshwater plants are able to multiply very fastly in appropriate conditions.



The species of main importance are \textit{Eichhornia crassipes} (water hyacinth) and Pistia stratoites (water lettuce). Water hyacinth, is able to double the surface of its growth in 6--18 days, whereas the biomass weight can reach up to 480 tons from hectar. In the biotop of its origin it is regulated by periodic rainy season and floods. Nowadays water hyacinth and water lettuce are spread pantropically all around the world. In the conditions where regular floods and changes of water level are missing, the waterweeds are causing serious problems. Plant cover reduces the amount of oxygen available for the ecosystem, it increases the evaporisation and water loss, it blocks the ship transport, making fishing almost impossible, but also it causes problems in irrigation channels and hydroelectric facilities. Biomass which can be obtained from the water weeds can be used not just in agriculture as composting material or mulch, but also it can be processed into energy by direct burning, peletisation or fermentation into biogas. 



There are many communities in the developing countries, which are settled on the rivershore, where all the firewood was chopped down. People have to collect the firewood and carry it for long distance, although the river is carrying  around constant amount of biomass which is in the form of  floating water hyacinths. These can be processed, mixed with litter and manure and used for biogas production. Biomass of invasive waterplants conceal great energetic potencial, although it seems to be just unproductively floating around.  



}

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\noindent \textbf{Keywords:} Aquatic plants,, Biomass, Eichhornia, Pistia, water weeds
\index[key]{Aquatic plants,}
\index[key]{Biomass}
\index[key]{Eichhornia}
\index[key]{Pistia}
\index[key]{Water!weeds}
\end{document}