Yemen was known historically as verdant Yemen because of its highly developed agricultural tradition. Rain- and spring-fed cultivated terraces cover the southern and northern highlands. Agriculture in the large valleys (wadis) on the Tihama coastal plain and in Hadramawt is spate (flood) irrigated. In the past 30 years, artesian wells have brought new lands into cultivation or permitted cash cropping on previously rainfed lands. The total amount of land cultivated, however, has declined as a result of urban migration and a new reliance on imported grain for food.

Even with rapid ur…