Strawberry Farmers in Monterey Fight Costly Battle as Hills Erode

Pickers were already moving along the well-drained sandy rows of strawberries on a field sloping steeply down from Gary Jertberg’s house northwest of here, the foliage and ripening fruit of each delicate plant resting neatly on sheets of plastic.

Jertberg’s 1985 crop emerged from the rainy season intact for the second straight year since he decided to take part in a pioneering effort to curb the severe erosion in the strawberry fields tucked into the rolling hills on either side of the Pajaro River, which separates Monterey and Santa Cruz counties.

Though the area’s gentle climate provides an exceptionally long growing season and the well-drained, sandy loam is ideal for cultivating the lucrative strawberry crop here, the hilly terrain creates an erosion nightmare: Soil losses run to 150 tons an acre per year--a layer of top soil about one inch deep. Not only is valuable soil lost, but an estimated 26,000 tons of sediment flows annually into the government-protected Elkhorn estuary to the west, filling in the tidal marsh behind the slough and threatening the fragile habitat of several rare species of wildlife that inhabit the sanctuary.

Sediment also damages downhill fields and yards, blocks county roads and has inspired the Monterey County Board of Supervisors to enact an erosion-control ordinance that holds growers subject to fines and liable for damages attributed to runoff--a move that might prod some farmers to emulate Jertberg but that has led others to take their land out of production.

Threatens Crop’s Future

As a result, erosion threatens the future of what has developed into Monterey County’s third most important crop, after lettuce and broccoli. Also, because strawberries must be picked by hand, the crop last year provided more than 4,500 nearly year-round jobs and pumped more than $101 million into the area’s economy, helping to make agriculture a $1-billion industry in Monterey County.

The erosion problem is evident in a canyon running south from Las Lomas just a few miles west of Jertberg’s fields. Here, the slopes fall even more steeply, as much as 33 feet every 100 feet, and home remedies--such as covering steep access roads with plastic--have been tried in a futile effort to keep the soil on the hills.

The result: Rains from the relatively mild winter carried off precious top soil, leaving deepening rills and gullies and stripping stretches of once-productive land.

The contrast is stunning. But Jertberg’s fields had looked like these a few winters back, before he concluded that the slopes required something far more extensive than the piecemeal measures that he had tried to channel runoff safely down the hills while leaving topsoil in place.

“It was a joke,” Jertberg recalled of his best efforts.

Joint Pilot Project

Jertberg and his neighbor, Manuel Gomez, finally agreed to join in a pilot project to demonstrate that the erosion can be contained, a cooperative effort sponsored by the local Resource Conservation District, Monterey County and the federal Soil Conservation Service--a unit of the Agriculture Department born 50 years ago this month in the wake of a disastrous series of dust storms.

In an inspired moment, the conservationists baptized the project area--which covers 4,700 acres between Highway 101 and Monterey Bay yet produces 27% of the nation’s strawberries--Strawberry Hills.

The Strawberry Hills challenge is substantial: Some fields that last year contributed to the record crop now barely hide the ravages of erosion under a protective cover of vegetation.

For example, just before Hidden Valley Road intersects with Strawberry Canyon Road, barley scarcely masks a sloping strawberry field taken out of production after winter rains carried soil onto the county road, subjecting its owner to a $250-a-day fine under the erosion-control ordinance. The county’s annual road-clearing bill in the area last year easily topped $100,000.

To protect their fields, growers tried planting grass on the access roads or laying strips of plastic over them. Some built “stairs” of catch basins to ease the runoff. Others installed “silt fences”--permeable fabric stretched between posts--in an effort to strain out the soil and let the water flow through.

Jertberg and many of the other growers had tried all these techniques and others.

Only Limited Success

“It isn’t as though the growers were not trying (to control erosion),” said Ronald D. Edwards, who heads the Soil Conservation Service’s Salinas office. “They were spending a lot of money and time in trying to correct the problems, but each of these home remedies worked only to a degree--not enough to do the whole job.”

With strawberries averaging gross income of more than $27,000 an acre in Monterey County, Edwards said, growers have a strong financial incentive to try to protect their crop.

Working with Jertberg, Strawberry Hills project leader Bruce Eisenman of the Soil Conservation Service designed a system that Jertberg said he at first rejected as more than his fields needed. But the severe winter of 1982-83 convinced Jertberg otherwise: Not only did he lose a lot of good soil, but property owners downhill from him also complained about the sediment. Then, too, there was the erosion-control ordinance.

“It was a real nightmare,” Jertberg recalled. “There were no two ways about it: It was not a question of cost, but of whether I wanted to grow strawberries.”

Under the project, a graded “diversion road” along the top of the field diverts runoff toward drains leading to a 24-inch pipe buried beneath the grassy access roads running vertically down the slope. Below the road, each row and furrow is graded in a 1% slope toward the drainage lines. Where each furrow meets the access road, a “pickup pipe”--6-inch buried corrugated plastic with a hole cut in the top at ground level--drains runoff from the field into the 24-inch pipe, which connects with the main drain at the base of the field.

Soil Filtered Out

The main drain flows into a basin, where any soil coming off the hill is filtered out for recovery at the end of the harvest, and the clear water passes on down a grassy water way to county-maintained culverts and ditches that carry it harmlessly to the Elkhorn estuary on Monterey Bay.

“I didn’t lose any sediment last year,” Jertberg said.

The Soil Conservation Service estimates that the Strawberry Hills project saved 2,787 tons of soil last year on 54 acres. All the same, Eisenman said, growers have been slow to invest the $1,500 an acre needed to install a comprehensive drainage system, even though the fields to be protected range in value from $2,000 to $10,000 an acre. Once installed, annual upkeep costs less than $375 an acre, he estimated. (Some of the worst-eroded fields are worked by sharecroppers who may be reluctant to invest in someone else’s property.)

“We’re at the stage now where we want to build up the confidence of the land users that something can be done,” said Jay Collins, head conservationist for the Soil Conservation Service’s nine-county central coastal area. So far, 10 pilot projects have been completed, Collins said, and another dozen systems are expected to go in after picking ends this fall.

Jertberg said many of his neighbors consider his installation “overkill”--designed as it was to cope with a once-in-25-years storm--especially since the last two winters have been mild. “In the back of my mind,” he confessed, “I’d sort of like to see a real heavy winter to see how it works.”

Eisenman agreed: “The test would be to have the same intensity and duration of rains (as in 1982-83), and compare.”