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\hypersetup{pdftitle={Benchmarking Wheat Grain Yield in Dry Environments of Iran Using Modelling Approach},pdfauthor={Reza Deihimfard, Mehdi Nassiri Mahallati, Alireza Koocheki},pdfsubject={Tropentag 2016: Abstract},pdfkeywords={APSIM, Cultivar, Simulation, yield gap},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{Benchmarking Wheat Grain Yield in Dry Environments of Iran Using Modelling Approach\footnote{\textbf{Contact Address:} Reza Deihimfard, Shahid Beheshti University , Environmental Sciences Research Institute, Evin Street, 1983963113~Tehran, Iran, \mbox{e-mail}: \email{deihim@sbu.ac.ir}}\\[0.8ex]}}
\normalsize{\textsc{Reza Deihimfard$^{1}$, Mehdi Nassiri Mahallati$^{2}$, Alireza Koocheki$^{3}$}}
\end{center}
\begin{itemize*}
\item[]{\small{\textit{$^{1}$Shahid Beheshti University , Environmental Sciences Research Institute, Iran}}}
\item[]{\small{\textit{$^{2}$Ferdowsi University of Mashhad, College of Agriculture, Department of Agronomy, Iran}}}
\item[]{\small{\textit{$^{3}$Ferdowsi University of Mashhad, Department of Agronomy, Iran}}}
\end{itemize*}
\index[author]{Deihimfard, Reza}
\index[author]{Nassiri Mahallati, Mehdi}
\index[author]{Koocheki, Alireza}
\begin{center}
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\textbf{Abstract}
\begin{abstract}
\normalsize{
Analyzing the yield gap, the difference between actual and potential yield, in the past is essential for maximising yield production in the future. To assess the yield gap in winter wheat in diverse dry environments of Khorasan province in northeast of Iran, APSIM crop model was calibrated and validated for three cultivars (Chamran, Sionz, Gascozhen). Long"=term (1987--2009) grain yield was simulated under three management scenarios (potential, water limitation and nitrogen limitation) for 14 locations across Khorasan province. The results revealed that there is a huge gap between the actual and potential yield (around 5.2 t ha-1) and farmers in the province have not been reached to the average simulated potential yield of 7.8 t ha-1. There was also considerable difference among cultivars in terms of yield gap. Averaged across locations and seasons, the total yield gap was obtained 4.4, 6 and 6.1 t ha$^{-1}$ for Chamran, Sionz and Gascozhen, respectively. Across locations, the percentage of yield gap ranged from \mbox{1.7\,\%} to \mbox{19.5\,\%} for water limitation, \mbox{40\,\%} to \mbox{47\,\%} for nitrogen limitation and 33 to \mbox{57\,\%} for other limiting and reducing factors.  The lowest yield gap was obtained in Sarakhs for Chamran (3.1 t ha-1) and the highest was obtained in Ghaen for Gascozhen (7.6 t ha-1). Overall, the results indicate that the average farmers' yield of about 2.6 t ha-1 under irrigated conditions in the study area is not limited by low genetic yield potential. Instead, low water availability, inappropriate timing of nitrogen application, and non"=adaptive cultivars for each environment recognised as key elements for increasing yield gap.}

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\noindent \textbf{Keywords:} APSIM, Cultivar, Simulation, yield gap
\index[key]{APSIM}
\index[key]{Cultivar}
\index[key]{Simulation}
\index[key]{Yield gap}
\end{document}
