The geography of Egypt is deeply important in understanding why the Egyptians centered their lives around the Nile. Both before and during the use of canal irrigation in Egypt, the Nile Valley could be separated into two parts, the River Basin or the flat alluvial (or black land soil), and the Red Land or red desert land. The River basin of the Nile was in sharp contrast to the rest of the land of Egypt and was rich with wild life and water fowl, depending on the waxing and waning cycles of the Nile. In contrast, the red desert was a flat dry area which was devoid of most life and water, regardless of any seasonal cycle.
The Nile in it's natural state goes through periods of inundation and relinquishment. The inundation of the Nile-a slightly unpredictable event- was the time of greatest fertility for Egypt. As the banks rose, the water would fill the man-made canals and canal basins and would water the crops for the coming year. However, if the inundation was even twenty inches above or below normal, it could have massive consequences upon the Egyptian agricultural economy. Even with this variability, the Egyptians were able to easily grow tree crops and vegetable gardens in the lower part of the Nile Valley, while at higher elevations, usually near levees, the Nile Valley was sparsely planted.
Agricultural crops were not the mainstay of the ancient Egyptian diet. Rather, the Nile supplied a constant influx of fish which were cultivated year around. In addition to fish, water fowl and cattle were also kept by the Egyptians. Flocks of geese were raised from the earliest times and supplied eggs, meat and fat. However, the domestic fowl didn't make its appearance until Ramesside times, and then in only very isolated places. The Egyptian farmers, in their early experimental phase, also tried to domesticate other animals such as hyenas, gazelles and cranes but gave up after the Old Kingdom. Cattle were also part of the staple diet of the Egyptians, suggesting that grazing land was available for the Egyptians during the times when the Nile receded. However, during the inundation, cattle were brought to the higher levels of the flood plain area and were often fed the grains harvested from the previous year.
The Egyptian diet was by no means limited to tree crops and vegetables, nor was it limited to an animal or fish diet. The Egyptians cultivated barley, emmer wheat, beans, chickpeas, flax, and other types of vegetables. In addition, the cultivation of grains was not entirely for consumption. One of the most prized products of the Nile and of Egyptian agriculture was oil. Oil was customarily used as a payment to workmen employed by the state, and depending on the type, was highly prized. The most common oil (kiki) was obtained from the castor oil plant. Sesame oil from the New Kingdom was also cultivated and was highly prized during the later Hellenistic Period.