Sonoma County’s ongoing wine grape boom held the countywide loss of irrigated farmland in recent years to just 117 acres, tempering a problem that elsewhere in California has eliminated wide swaths of productive agricultural land, according to a new state report.
The net loss of irrigated farmland amounts to a sliver of Sonoma County, which spans about 1 million acres, and about 0.15 percent of its 80,000 agricultural acres. Sonoma had the smallest net loss among the 47 counties included in the report, ranking it just behind 10 counties — including Mendocino — that had net gains in irrigated farmland.
The California Farmland Conversion Report, issued by the Department of Conservation, documented gains and losses of urban and agricultural land from 2008 to 2010.
Sonoma County lost 2,424 acres of irrigated farmland, with nearly 70 percent of the gross loss due to fallowing of pastures for at least six years. Only 45 acres of irrigated farmland were lost to urban development.
The gross loss was nearly offset by a gain of 2,307 acres of irrigated farmland, most of it for new vineyards installed from 2008 to 2010, the report said.
“The county is in a pretty stable situation,” said Molly Penberth, manager of the state’s Farmland Mapping and Monitoring Program, which produced the report.
Conversion from dry to irrigated land is feasible only for high-value crops like grapes, she said. “You guys are sitting pretty well over there.”
Sonoma County growers planted 2,100 acres of new vineyards from 2008-10, according to county crop reports, followed by the same amount of planting from 2011-13. The county’s 2013 grape harvest was worth more than $600 million.
Little urban growth
The recession limited net urban growth to 473 acres in the county during the report period. Most of the growth was in new housing, schools and schoolyards. The county’s urban growth ranked fourth in the San Francisco Bay Area, behind Santa Cruz with a net gain of 737 acres, San Mateo with 638 acres and Contra Costa with 629 acres.
Statewide, loss of valuable farmland has been a rising concern, especially in the Central Valley, as acreage is fallowed en masse, including 34,000 acres in Fresno County alone from 2008 to 2010. The eight-county San Joaquin Valley — at the heart of California’s $43 billion farm economy — accounted for half of the statewide 168,000-acre net decrease in irrigated land from 2008 to 2010. Most of the decrease was due to drought-related land idling, the state report said.
Since the mapping program began in 1982, more than 1.4 million acres have been removed from farming in the state, with nearly half of those acres designated as “prime farmland” based on soil quality and irrigation status.
“That’s about a square mile every four days for a total area bigger than Merced County,” Penberth said. California remains the nation’s agricultural production leader, but farmers and ranchers are “continually trying to do more with less,” she said.
A single pasture
Tony Linegar, Sonoma County’s agricultural commissioner, said the county’s reported net loss of 117 acres of irrigated land was the equivalent of a single pasture.
For livestock ranchers, it is “standard practice” to cull herds and fallow pastures during dry periods, he said.
Letting pasture land go dry is also the first step toward vineyard conversion, Linegar said.