CAIRO, Oct 17( Reuters)-Emirati agribusiness Al Dahra is in talks to acquire more agricultural land in Egypt, two sources with direct knowledge of the matter said, in a deal that could reduce Cairo's dependence on imports of staple crops but also reignite water use concerns. The sources did not say how close a deal might be, but the investment could potentially involve hundreds of millions of badly-needed dollars to reclaim desert and grow key crops such as wheat and corn.Al Dahra, half owned by