Quantifying the yield potential and gap between average farmer yields and yield potential is essential to estimate future food production capacity and to improve policies and research to ensure local food security. In order to quantify potential yield, yield gap and identify the spatial variation of corn yield, crop simulation model and Geographic Information System (GIS) were employed across Khorasan provinces (Northern, Razavi (Central), Southern) in northeast of Iran. The CSM-CERES-Corn model performed well to simulate yield of corn in this region. Results showed that average potential yield of corn was 16.4, 14.1 and 10.2 t ha-1 for Northern, central and Southern parts of Khorasan province respectively. It seems that the high temperature in the Southern part is the limiting factor. The high yield gap of 9.7, 8.61 and 6.28 t ha-1 was estimated for Northern, central and Southern of Khorasan province, respectively. Regions with higher yield potential showed a higher yield gap. Results of the study will facilitate identification of limiting factors for improvement of current corn yield in the area.

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