In the harsh, isolated, semi-desert region north of Cairo in Egypt, 150 acres has been planted with beans, peas and orange trees. But there is a problem: an endless need for water. Farmer Tantawi Mostafa explains: “Each plant needs a certain amount of water, depending on the season. Peas, for instance, need a lot of water, I have to irrigate them at least five hours a day. Oranges and…