Soil salinity continues to be a concern around the Paso Robles area, according to Mark Battany, San Luis Obispo County UC Farm Advisor. Problems with salinity vary from year to year. Battany started conducting periodic soil salinity surveys in 2006 to determine the extent of the problem.
“Salinity issues here are very different from other areas of California, such as the northern coast, for example,” he says. “We have drier conditions, a different quality of irrigation water, and less leaching rainfall. In some years, you have symptoms showing up pretty significantly, in other years not so much.”
In general, however, growers have been reporting more issues with salinity recently. Researchers aren’t exactly sure why. It could be any number of factors, according to Battany.
“We’ve had a large increase in grape acreage. There’s also been a big shift in the types of varieties we’re growing. We’re only growing about 14 percent of whites now in this area. There have also been changes in irrigation practices. Previously, almost everything was sprinkler irrigated. Now it’s primarily drip. Additionally, there’s been a lot more deficit irrigation.”