Continuous ponding and shallow aquifer pumping leaches salts in clay soils

Poor water penetration and high soil salinity can be particularly detrimental to crop production in arid regions. In the Imperial Valley, roughly half of the crop acreage is planted on clay soils with very low water infiltration rates. A 30-year study showed that traditional subsurface-drainage systems provide limited control of soil water content and salinity in the root zone in clay soils underlain by artesian aquifers. In a more recent 3-year study at the UC Desert Research & Extension Center, a shallow drainage-well system improved water movement through the soil profile and was useful in leaching salts from clay soils only after continuous surface ponding and groundwater pumping. Continuous ponding for 1 month was sufficient to leach some of the salt deeper in the heavy soil.