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\hypersetup{pdftitle={Restoring of Soil Fertility in a Wheat"=gaur Rotation System with Organic Waste},pdfauthor={Fatooma Ali Mohame Rezig, Elsadig Elhadi, Mubarak Abdalla},pdfsubject={Tropentag 2016: Abstract},pdfkeywords={Crop residues, Guar., Sewage sludge, Soil properties, Wheat},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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\begin{center}
\Large{\textbf{Restoring of Soil Fertility in a Wheat"=gaur Rotation System with Organic Waste\footnote{\textbf{Contact Address:} Mubarak Abdalla, University of Khartoum, Desertification and Desert Cultivation Studies Institute, 13314~Khartoum, Sudan, \mbox{e-mail}: \email{mubarakgeziraaba@gmail.com}}\\[0.8ex]}}
\normalsize{\textsc{Fatooma Ali Mohame Rezig$^{1}$, Elsadig Elhadi$^{2}$, Mubarak Abdalla$^{3}$}}
\end{center}
\begin{itemize*}
\item[]{\small{\textit{$^{1}$National Center for Research,  Environment\& natural resources\& Desertification Research Institute, Sudan}}}
\item[]{\small{\textit{$^{2}$National Center for Research, Environment\& natural resources\& Desertification Research Institute, Sudan}}}
\item[]{\small{\textit{$^{3}$University of Khartoum, Desertification and Desert Cultivation Studies Institute, Sudan}}}
\end{itemize*}
\index[author]{Rezig, Fatooma Ali Mohame}
\index[author]{Elhadi, Elsadig}
\index[author]{Abdalla, Mubarak}
\begin{center}
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\textbf{Abstract}
\begin{abstract}
\normalsize{
Recycling of organic residues is important in restoring fertility of degraded soils. The aim of the study is to evaluate the contribution of crop residues, sewage sludge, and exotic humentos on some soil properties after continuous cultivation (wheat- gaur) for five seasons. Wheat and guar were cultivated in a rotation in a sandy clay loam soil during 2008--2010. The field experiment consisted of six treatments (i) control (no fertilisers no crop residues, C), (ii) Crop residues (CR), (iii) humentos imported from Germany applied at 200 kgha$^{-1}$ (H), (iv) Sewage sludge applied at 10 tha$^{-1}$ (v), inorganic fertiliser without crop residues (IF) and (vi) inorganic fertiliser with crop residues (IF +CR). The experimental units were arranged in a randomised complete block design with four replicates. After the fifth season, soil chemical properties (pH, total nitrogen, organic carbon, available phosphorous, soluble potassium, mineral nitrogen and cation exchange capacity and soil physical properties (water holding capacity and bulk density). were determined. The results obtained showed that, recycling of organic wastes increased significantly soil organic carbon by \mbox{794\,\%}, cation exchange capacity by \mbox{80.1\,\%}, available P by \mbox{131.9\,\%}, total nitrogen by \mbox{214.3\,\%} and mineral nitrogen by \mbox{176.3\,\%} and water holding capacity by \mbox{15.4\,\%}. On the other hand, incorporation of organic waste decreased soil pH by \mbox{8.5\,\%} and soil bulk density by \mbox{9.2\,\%}. Based on this study, incorporation of crop residues, crop residues with inorganic fertilisers and sewage sludge could be a beneficial practice for improving the fertility of nutrients poor sandy clay loam soil.}

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\noindent \textbf{Keywords:} Crop residues, Guar., Sewage sludge, Soil properties, Wheat
\index[key]{Crop!residues}
\index[key]{Guar.}
\index[key]{Sewage sludge}
\index[key]{Soil!properties}
\index[key]{Wheat}
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