The demise of a number of ancient Mesopotamian civilizations dependent on irrigation, as well as the abandonment 700 years ago of agricultural settlements in the American Southwest, have been traced to salt buildup, drought, and/or erosion. Even today, 550,000 acres (222,750 ha)of irrigated land are going out of production each year due to salt buildup in arid land regions of the world [1]. Cooperative planning by USDA with state and federal agencies has been underway since 1973 to reduce salinity problems in the Colorado River Basin. The experience gained in planning and implementing onfarm salinity control measures will prove valuable in other parts of the country--valuable enough to save dollars, time, farms, and perhaps even portions [...]