\documentclass[english,german]{scrartcl}
\usepackage{fontspec}
\usepackage{geometry}
\geometry{verbose,a4paper,tmargin=1.75cm,bmargin=2cm,lmargin=2cm,rmargin=2cm,headheight=0.8cm,headsep=0.5cm,footskip=0.5cm}
\usepackage{babel}
\usepackage{url}
\urlstyle{same}
\newcommand\email{\begingroup \urlstyle{same}\Url}\usepackage{graphicx}
\usepackage{units}
\usepackage{tabularx}
\usepackage{wasysym} % enable use of \permil instead of \textperthousand
\usepackage{marvosym}
\usepackage{hyphenat}
\usepackage{booktabs}
\usepackage{mdwlist}
\renewcommand{\thefootnote}{\relax}
\usepackage{index}
\newindex{key}{kdx}{knd}{Keywords}
\newindex{author}{idx}{ind}{Authors}
\usepackage{fancyhdr}
\pagestyle{fancy}
\renewcommand{\headrulewidth}{0pt}
\fancyfoot{}
\usepackage{ifpdf}
\ifpdf
%\usepackage[activate]{pdfcprot}
%\usepackage[owner=Tapioka, print=true, copy=true, edit=false, annotate=false,set]{pdfcrypt}
%encryption: not supported any more (since pdftex 1.10)
\usepackage[pdftex]{thumbpdf}
\usepackage[pdftex]{hyperref}
\hypersetup{pdftitle={Patterns and Drivers of Soil Carbon Dioxide Emissions from Well"=Watered and Drought"=Stressed Silage Maize Production},pdfauthor={Khatab Abdalla, Mutez Ahmed, Johanna Pausch},pdfsubject={Tropentag 2020: Abstract},pdfkeywords={Carbon sequestration, ecosystem, microbial biomass, soil respiration},pdfpagemode=None,colorlinks=true}
\else
\usepackage{textcomp}
\fi
\begin{document}
\ifpdf
\parbox[b]{2.5cm}{\resizebox*{2.5cm}{!}{\includegraphics{dtt2020.jpg}}}
\else
\parbox[b]{2.5cm}{\resizebox*{2.5cm}{!}{\includegraphics{dtt2020.eps}}}
\fi
\hfill
\parbox[b]{13.4cm}{\centering \large{\textbf{Tropentag, September 9-11, 2020, virtual conference}}\\[1ex] \Large{``Food and nutrition security and its resilience\\ to global crises''\\[2ex]}}
\hspace{0.1cm}
\begin{center}
\Large{\textbf{Patterns and Drivers of Soil Carbon Dioxide Emissions from Well"=Watered and Drought"=Stressed Silage Maize Production\footnote{\textbf{Contact Address:} Khatab Abdalla, University of Bayreuth, Agroecology, Universitätsstraße 40, 95447~Bayreuth, Germany, \mbox{e-mail}: \email{khatab.abdalla@uni-bayreuth.de}}\\[0.8ex]}}
\normalsize{\textsc{Khatab Abdalla$^{1}$, Mutez Ahmed$^{2}$, Johanna Pausch$^{1}$}}
\end{center}
\begin{itemize*}
\item[]{\small{\textit{$^{1}$University of Bayreuth, Agroecology, Germany}}}
\item[]{\small{\textit{$^{2}$University of Bayreuth, Soil Physics, Germany}}}
\end{itemize*}
\index[author]{Abdalla, Khatab}
\index[author]{Ahmed, Mutez}
\index[author]{Pausch, Johanna}
\begin{center}
\vspace{1.1cm}
\textbf{Abstract}
\begin{abstract}
\normalsize{
The projected global warming risks due to high emissions of greenhouse gases, mainly from anthropogenic activities, increases the need for an agricultural practice with high carbon sink capacity and water use efficiency without compromising on food security. On one hand, it’s well accepted that soil temperature and moisture content directly affect microbial activity, whereas on the other hand, drought stress was recently postulated to increase root exudates, which in turn will accelerate soil organic matter mineralisation. Thus, the objective of this study was to investigate the interplay between soil moisture (well"=watered and drought stressed) and maize (\textit{Zea mays} L.) root exudates on soil CO$_{2}$ efflux. The experiment consisted of three treatments, which are well"=watered, drought stressed maize plus a control (without plants). Soil CO$_{2}$ efflux, soil temperature and moisture content were measured weekly during the growing season (April to September) and monthly in the fallow period. Under well"=watered conditions, the annual average of CO$_{2}$ efflux was 0.12 g CO$_{2}$-C m$^{-2}$ hr$^{-1}$, which was 24.5\% and \mbox{20\,\%} significantly higher than under drought stressed and the control, respectively. Moreover, well"=watered treatment had significantly greater primed carbon than drought stressed maize. Soil temperature in deeper soil layers (25, 50 and \mbox{75\,cm}) correlated positively with the CO$_{2}$ efflux, while soil moisture correlated negatively at the \mbox{5\,cm} and \mbox{25\,cm}. In addition, above and below ground biomass correlated significantly to soil CO$_{2}$ efflux. Overall, these results suggested that the root exudates decreased under drought conditions, which decreasing soil respiration. Drought tolerance varieties could be an option to decrease soil respiration and maintain productivity.}

\vspace{0.5cm}
\end{abstract}
\end{center}
\noindent \textbf{Keywords:} Carbon sequestration, ecosystem, microbial biomass, soil respiration
\index[key]{Carbon sequestration}
\index[key]{Ecosystem}
\index[key]{Microbial biomass}
\index[key]{Soil!respiration}
\end{document}
