I have read that Ancient Egypt was slightly more lush than it is today, however, this was still entirely concentrated around the Nile. Beyond that mighty river, the desert sands were still just as dry as they are today. Furthermore, the Nile Delta (as seen in this satellite photo) is particularly fertile and very much different from the common conception of Egypt. While North Africa was wetter in pre-historic times, by the time of the Pharaohs, the Sahara had become "fully desiccated" and indeed, a severe drought in 2200 BCE likely triggered the collapse of the Old Kingdom. By 1250 BCE, Egypt's climate was about as dry as it is today and its civilization hugged the Nile River. To combat this, Ramses II built some of the most impressive canalworks of the day in his new city Per-Ramses.

One thing that may have triggered your question was the fact that Egypt used to be the Mediterranean's largest producer of grain, exporting it to every corner of the basin and famously feeding the city of Rome from the time of Egypt's subjugation by Augustus to the fall of the Empire. I'm struggling to find a citation for Egypt's decline from grain exporter to reportedly the largest importer of grain in 2011. However, I do remember reading that it had to do with overworking the soil, which, in the desert climate can easily turn to dust and blow away. Further, as the river has changed its course, it's going to be running through sand, rather than rich sediment which will hurt the riparian farming that goes on next to it. I'm not sure how much effect this has over time, but it could be significant.

I have an excellent book with some good illustrations of Egyptian agriculture and depictions of the river and its surroundings (Egypt: Land of the Pharaohs by Time-Life Books), but unfortunately I have no way to get them onto the internet. Sorry!