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\hypersetup{pdftitle={Efficiency of an Agrosystem Designed for Family Farming in the Pre"=amazon Region},pdfauthor={Emanoel Gomes Moura, Alana Das Chagas Ferreira Aguiar, Idelfonso Colares},pdfsubject={Tropentag 2010: Abstract},pdfkeywords={Leguminous, maize productivity, nutrient recycling, soil organic matter, 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{Efficiency of an Agrosystem Designed for Family Farming in the Pre"=amazon Region\footnote{\textbf{Contact Address:} Emanoel Gomes Moura, Maranhão State University, M.sc. Course in Agroecology, Brazil, \mbox{e-mail}: \email{egmoura@elo.com.br}}\\[0.8ex]}}
\normalsize{\textsc{Emanoel Gomes Moura$^{1}$, Alana Das Chagas Ferreira Aguiar$^{2}$, Idelfonso Colares$^{3}$}}
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\begin{itemize*}
\item[]{\small{\textit{$^{1}$Maranhão State University, M.sc. Course in Agroecology, Brazil}}}
\item[]{\small{\textit{$^{2}$Maranhão State University, M.sc. Course in Agroecology, Brazil}}}
\item[]{\small{\textit{$^{3}$Maranhão State University, M.sc. Course in Agroecology, }}}
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\index[author]{Moura, Emanoel Gomes}
\index[author]{Ferreira Aguiar, Alana Das Chagas}
\index[author]{Colares, Idelfonso}
\begin{center}
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\textbf{Abstract}
\begin{abstract}
\normalsize{
In the humid tropics the continuous use of the same area reduces nutrient availability and increases the incidence of weeds. To circumvent these obstacles, farmers in the pre-Amazon region practice itinerant agriculture associated with the slashing and burning with negative effects on the local and global environment because  reduces biodiversity, impoverishes ecosystems and contributes to carbon emissions. In the search for a suitable system for humid tropical agriculture, the objective of this study was to investigate the performance of no"=till alley cropping in conjunction with the use of annual legume crops grown during the off"=season. The experiment was implemented in a one"=hectare alley cropping system in which was used the leguminous tree clitoria (Clitoria fairchildiana R.A. Howard). The experimental design consisted of randomised blocks with four replications of the following treatments: stylosanthis, showy rattlebox, sunn hemp, jack bean and clitoria alone. In January 2007 and 2008, maize was planted in each alley. One hundred twenty days after annual legumes were sown; its total biomass was collected. Weed incidence was assessed 35 days after maize planting. Analyses of the C, N, P, K, Ca and Mg contents of the legumes were carried out. To assess SOM, soil samples were collected, and two adjacent areas were also sampled: a ten"=year-old secondary forest and an area of conventional tillage. The SOM was fractionated using a densimetric and a granulometric method. The use of legumes in no"=till systems may be more environmentally appropriate than conventional systems that reduce the silt and free light organic matter fractions of the soil.  The soil management in this system changes the composition of the weed community, replacing the more aggressive types with those less competitive. From an agronomical point of view, the use of Crotalaria spectabilis may be an effective strategy for reducing weed density in the primary crop. Furthermore, relative to the use of leguminous trees alone, higher yields of maize can be obtained with the use of showy rattlebox and sunn hemp without the application of additional N. }

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\noindent \textbf{Keywords:} Leguminous, maize productivity, nutrient recycling, soil organic matter, weeds
\index[key]{Leguminous}
\index[key]{Maize productivity}
\index[key]{Nutrient!recycling}
\index[key]{Soil!organic matter}
\index[key]{Weeds}
\end{document}