COLUMN ONE : Pollution Is Choking Farm Belt : Smog in the San Joaquin Valley is producing lower crop yields and higher consumer prices. A few farmers have emerged as activists.

Alongside the straight, flat roads that crisscross Fresno County, the farm belt fields bear witness to a grower’s ability to manage the environment. The nights are cold? Farmers cover each tomato plant with a white paper cap to ward off the chill. Lack of sun is stunting growth? They prune their plum trees into funnel shapes to let light pour over inner branches.

Now, a tougher problem looms, literally, on the horizon. To the east, where the Sierra Nevada are said to soar, the mountains hide behind a milky veil with a brownish cast. It is the air.

California’s notorious smog is not restricted to the Los Angeles area. Bakersfield is the second smoggiest spot in the United States; Fresno is third, ahead of New York City and Chicago. Air quality in the San Joaquin Valley has worsened to the point that ozone, a primary pollutant, is choking crops.

University of California experiments show that ozone in levels found here--about half those in Southern California--reduce yields of cotton by 20%, table grapes by 25%, and Valencia oranges by 25%.

The victims are the captains of agriculture--the state’s largest industry--and everyone who buys their produce. A 1990 state study estimates that in any year, growers lose up to $200 million to pollution and consumers lose $184 million in higher prices at the grocery store.

By and large, farmers believe the figures. Most around here react like Don Cameron, manager of the 5,000-acre Terranova Ranch.

“Anything that affects yields, we’re interested in,” he said, standing in the trailer from which he directs the cultivation of alfalfa, cotton, raisins, wine grapes, wheat and oats. “But the ozone, how are we going to control that?”

In the long run, researchers say, there is only one solution: Clean the air. “You would think,” plant physiologist David A. Grantz said of the growers, “that they’d be up in arms about it.”

That answer is unsettling to growers, who tend to view environmentalists as an overzealous, regulation-happy lot. After all, to them, environmentalists are the folks who want to curtail use of pesticides and cut agriculture’s share of water. It does not matter that, for once, agriculture is not cast as the villain; rapid urban sprawl and industrialization appear to be the culprits.

A few farmers and farm organizations have emerged as activists, fighting construction of smog-producing electric and steam-generating plants in southern sections of the valley. However, “the message that we get from the farming community is still very mixed,” said Mary Shallenberger, consultant to the state Senate Natural Resources and Wildlife Committee.

Scientists and politicians may call on agricultural interests to campaign on a large scale to rein in emissions from motor vehicles, refineries, dry cleaners and the like, but “you won’t see it (happen),” said R.G. (Skeet) Trapnell, a cotton gin manager who heads the citizens advisory board for the valley’s new air quality district. Trapnell got involved only because his boss, when asked, did not want to serve and passed the task along.

Influence all you can, goes the farmer’s creed, and live with what you have to, be it demon drought or winter freeze. Consequently, said Grantz, “they tend to look at ozone as an act of God” rather than as something they can change.

Air pollution is a particularly nebulous foe, more easily ignored than other perils. The damage is not visible to someone standing in a field. The fruit, the vegetables, the cotton bolls, for the most part, look just fine. There are simply fewer of them.

When Robert F. Brewer started conducting the first ozone experiments on valley crops in the early 1970s, he did not believe there was a problem.

A horticulturist, he had moved from the UC Riverside campus to its Kearney Agricultural Research Station, southeast of Fresno, to try out methods for coping with crop frost and heat stress. Harvests of cotton, a major valley crop, had been heading downhill for 20 years. “Yields were going down 5% or 10% a year and you can’t do that too long and stay in business,” he said. “Things were in a tailspin.”

He scoffed at theories that air pollution was to blame. Compared to Riverside, the valley seemed fresh and pure. But when some cotton seed distributors put up research money, Brewer dutifully set out special chambers around plants in the fields, allowing the surrounding air to reach some and filtering out impurities for others.

“Lo and behold, we had tremendous differences,” Brewer said. “This just about knocked our hats off.”

He spent years testing and re-testing his data, which showed that different strains of cotton grown in clean air produced 15% to 20% more than in polluted valley air. Other scientists were skeptical and duplicated Brewer’s studies to see for themselves. They were astounded when they got similar results.

In the mid-1980s, the research pace picked up. At the Kearney station, at a U.S. Department of Agriculture site near Bakersfield, and on the UC Riverside campus, ozone was found to dampen production of black-eyed peas, dry beans, alfalfa, almonds, oranges, grapes, sweet corn and tomatoes.

Other crops seemed relatively unaffected: lettuce, peaches, nectarines and barley. No one understands why.

Now, the fruit of the month at the Kearney station is Casselman plums. On April 1, more than 200 trees were surrounded by walls of plastic stretched across aluminum frames. Each chamber shelters four trees. The enclosures will not come down until the growing season is over in November.

As in Brewer’s experiments, the air is left undisturbed in some chambers and charcoal filters screen out pollutants in others. A third set is fed by tubes carrying a metallic-smelling gas. It is pure ozone, in quantities that keep the interior atmosphere at twice the pollution level outside. What happens in the double-ozone chambers provides a glimpse of farmers’ prospects if the air gets as dirty as that south of the Tehachapi Mountains.

For three growing seasons, plant physiologists Larry Williams and William Retzlaff have nurtured, measured and monitored these same trees. They have recorded significant differences. The higher the ozone level, the smaller the trunk’s circumference. Pollution leads to fewer flowers forming in the spring and more leaves dying sooner in the fall.

Late last summer, the trees exposed to the highest ozone burst into a second, very light bloom. “That’s a response to stress,” Williams said. “That’s what happens when you think you’re going to die; you try and get that next generation out into the world.”

Most important, the trees in filtered air each produced an average of 139 marketable plums. In valley air, the average yield declined to 101, a 27% decrease. In the double-ozone chambers, the average was 90.

As the trees mature, Williams and Retzlaff hope to discover how ozone inflicts its damage. Does it slow photosynthesis? Does it render flowers infertile? Does one season’s pollution affect the next year’s crop?

Ozone researchers see their task as urgent. “If the amount of acres needed to produce the same amount of crop could be reduced, then agriculture would have less environmental impact,” said Randall G. Mutters, a UC Riverside plant physiologist. “There would be less water used and less insecticide applied.

“And it’s important,” he said, “as urbanization and industrialization continue in the valley, to make the best use of the farmland that’s left.”

None of them expect the region’s air to improve soon. While the Los Angeles Basin is considered a hospitable breeding ground for smog, at least the coastline provides an outlet for Santa Ana winds to sweep pollution out to sea. The valley, on the other hand, is like a tub without a drain. It is completely ringed by mountains.

The State Air Resources Board, county governments and private companies are financing a study to determine the sources of the ozone. The general air patterns are known. Wind flows from the populous Bay Area through the urbanizing Sacramento Delta and turns south into the valley, one of the fastest-growing portions of the state. Car exhausts, industrial solvents, paint vapors, refinery fumes and other detritus of modern life are swept along, reacting in the sunlight to form smog. The pollution piles up in the south and to the east, against the Sierra--where crop loss rates have been the highest.

Locals in their 30s and 40s wax nostalgic about their youth, when they could stand on the valley floor and pick out trees and jagged outcroppings of rock in the Sierra. “Now you can’t even see the buildings of Fresno. It’s just a haze,” said Wanda Ginder, who lives in Selma, about 20 minutes southeast of the city.

When growers first heard that the dirty skies were affecting their harvests, they turned to the chemical industry for help. They tried sprays with names such as Ozoban, designed to reduce ozone to harmless atmospheric oxygen. Their performance, said Brewer, was erratic.

Some scientists tout the breeding of smog-resistant crops as an interim measure to boost production until the air is cleansed. “We can probably find out the genetic basis of resistance and develop crops in seven years,” said Brian Mudd, director of UC Riverside’s air pollution research program. “It will take 20 years or more to reduce smog to federal standards.”

In one sense, work on smog-resistant varieties has begun. Six years ago, Delta Pine and Land Co., a Mississippi seed firm, stationed breeder Elmer Gilbert in Visalia. Delta officials had noticed that their seeds “adapted all over the world, but when we brought them into this valley and tested them, the leaves turned yellow. The plants died earlier,” Gilbert said.

Gilbert’s mandate was to create new varieties for the valley. He did not know how to select for smog resistance, but figured that those strains that prosper here must have it.

The notion is practical, but it makes Gilbert sad. “Our seeds here can produce 98% of the standard, but without pollution it would be 10%, 15% more,” he said. “This valley without the pollution would be the best place to grow cotton in the world.”

The valley is taking its first hesitant steps toward a regional air cleanup effort. Last month, to head off a bill sponsored by state Sen. Dan McCorquodale (D-San Jose), the farm belt’s eight counties formed a unified air pollution control district with representatives of each board of supervisors, similar to the South Coast Air Quality Management District. The acting director, a management consultant with no previous pollution experience, answers his own phone and takes down the folding chairs after board meetings.

Two weeks ago, at the district’s first formal meeting, staff members explained to the board that an ambitious proposal to charge developers for pollution caused by new projects would have to be watered down and postponed.

Farmers have had little to say about the matter. They have their reasons for not getting involved.

First, said Trapnell, growers worry that speaking out in favor of regulating others could backfire. They could be forced to equip their tractors with catalytic converters, replace them with electric machines or, even worse, refrain from using their equipment except on days when bureaucrats give the word.

There is also the prospect that if farmers start talking about ozone, others will focus on dust, another pollution problem that may force changes in agricultural practices, such as burning raisin trays and field stubble.

Then there is the political theory: “The Democrats,” Trapnell said, “want to make an issue of air quality to stop growth here and reduce the impact of the San Joaquin Valley, which seems to be conservative.”

Besides, growers doubt their clout. “I’m realistic. I know people aren’t going to listen to us,” said Mel Kazarian, who farms 1,200 acres near Fowler. “We’re a small voice.”