It’s hard to believe that ancient seas once covered a large part of California’s San Joaquin Valley—until you check the soils.
That’s when you’ll discover that those seas left behind marine sediments, shale formations and deposits of selenium and other minerals in the soil. Crops grown in the valley must be irrigated, but the runoff irrigation water can carry high levels of selenium that can be toxic to fish, migratory birds and other wildlife that drink from nearby waterways and drainage ditches Read more (USDA blog).