Once a dusty stagecoach trail, Highway 99 has served for nearly 80 years as Main Street for the most productive swath of farmland in the world.
Rice paddies and almond orchards stretch alongside the highway in the northern Central Valley. They give way to cotton and wine grapes through the heart of the state, and then dairies and hay as the highway nears the valley's southern end in Bakersfield.
More than 250 crops, all told, power the valley's $17 billion farm industry.
But Mediterranean-style houses, mini-marts and power centers are edging out crop rows along the highway's 450 valley miles. More than 2.5 acres of irrigated land are taken out of production each hour in the Central Valley, according to state estimates.
Valley residents once indifferent to farmland loss now are trying to slow it by ballot measure, buying development rights and building political alliances.
"Ten years ago, we didn't have the people in the valley that we have today," said Donald Bo, an Acampo real estate appraiser and president of the new Central Valley Farmland Trust. "We always knew about the Bay Area -- those people who come over the hill. They are over the hill now."
The valley will be the state's fastest-growing region for several decades, its population swelling about 130 percent to nearly 13 million by 2050. It contains five of the state's 15 largest cities: Fresno, Sacramento, Bakersfield, Stockton and Modesto.
Despite the boom, farmland conservation efforts in California historically have focused on the coast. One state program has spent more than $9.3 million buying development rights in Monterey County, compared with $12.5 million spent for all 18 Central Valley counties.
"You can see what you are protecting" in protected coastal valleys, said recently retired University of California farmland expert Al Sokolow. "It's harder to see it in the great expanse of the Central Valley."
What you can see driving on Highway 99 in the valley are places so marred by litter, billboards and junkyards that the road is more like a back alley than Main Street. What you can't see most of the year: mountains obscured by smog on either edge of the 50-mile-wide valley.
"The 99 corridor between Sacramento and Yuba City could end up looking like it does between Sacramento and Modesto," lamented Nicole Van Vleck, managing partner of Montna Farms in Yuba City.
Thousands of acres gone
Between 1990 and 2002, 283,000 acres of irrigated valley farmland were converted to other uses -- nearly 4 percent of the valley's 7.4 million acres of irrigated land.
The valley is the largest splotch of bright red on a map highlighting U.S. farmland endangered by urban encroachment. American Farmland Trust, one of the major national farmland protection advocates, produced the map.
"The valley is the world's No. 1 agriculture resource," said California Director Edward Thompson Jr. "You just can't find anything else like it on the planet."
He said the influence of suburban sprawl is greater than numbers suggest. "For every acre that is taken out (of production), you have two to three acres that fall under the shadow" of development, Thompson said.
That could mean more traffic, neighbors who don't care to be awakened at dawn by tractors and schools that must be protected from pesticides.
However, new technologies likely will allow California ag revenue to outpace farmland loss for the foreseeable future.
Advances in plant varieties, farming techniques and equipment historically have more than made up for lost farmland, said Dan Sumner, director of the University of California's Agricultural Issues Center in Davis. He predicts the value of California's farm production will increase by more than 50 percent in the next 30 years -- enough to stay ahead of population growth.
"We know there are some limits here," he said. "But at least by most measures, California is (expected) to produce more, not less, even though we are using less land."
Valley residents say their concerns go beyond the food supply. They worry about losing their "quality of life" -- a phrase that encompasses everything from abundant wildlife and friendly neighbors to open spaces.
"In many cases, agriculture provides more than just what you see on the surface," said Molly Penberth, manager of the state's Farmland Mapping and Monitoring Program.
About three years ago, Van Vleck's family, led by rice farmer Al Montna, locked up a 1,200acre rice ranch on Highway 99 near Yuba City. They sold their development rights for an undisclosed amount to a unit of the conservation group Ducks Unlimited.
"We didn't want to see it built up into strip malls," she said.
Now, Ducks Unlimited is working with other farmers around Yuba City.
"We are trying to get a critical mass up there," said Olen Zirkle at the regional office of Ducks Unlimited in Rancho Cordova.
Land trusts usually offer between 20 percent and 50 percent of a property's market value in a one-time payment that keeps the land undeveloped "in perpetuity." Money comes from private foundations, state grants and fees paid by developers to offset development impacts.
Many such programs are expanding, said Sokolow. He estimates there are 200,000 to 250,000 acres of permanently protected farmland statewide.
The most prominent statewide farmland preservation effort is the California Land Conservation Act, better known as the Williamson Act. The 1965 law saves farmers and ranchers 20 to 75 percent in tax liability each year if they forgo development for at least 10 years. The program has about 16.6 million acres at a cost of $39.2 million.
State subsidizes protection
Farmland protection gets its own office in the state Department of Conservation, which has spent $43 million since the mid-1990s on roughly 80 permanent farmland easements covering more than 25,000 acres.
Valley development concerns were highlighted on the November ballot in several counties.
In San Joaquin County, for instance, six ballot measures took on growth and open space -- proposing everything from setting development boundaries to protecting farmers' rights.
Projections show more than 900,000 people will live in San Joaquin County by 2025, a 59 percent increase from 2000.
Farmland protection is bold business for farmers who otherwise could sell their properties -- especially those with easy highway access -- for as much as $100,000 an acre. Developer money is easy to find, while trusts can have a hard time coming up with easement money.
Despite such uncertainties, Bo is shepherding the new effort to coordinate conservation efforts along the Highway 99 corridor in Sacramento, San Joaquin, Stanislaus and Merced counties.
"Without proper guidance, development could transform the Central Valley into another version of the Los Angeles Basin, with urban sprawl supplanting much of its agricultural land and virtually wiping out production agriculture," the American Farmland Trust warned in recent comments.