It began with green beans in Oregon and apples in Walla Walla and here he was now, a decade later, picking cucumbers, living in the hellacious heat of a one-room corrugated metal shack on the Easdtern Shore and wondering literally when the next meal would come from.

The cucumbers had run out days before around Hurlock, where Ronald Robichaud was encamped with his wife and three young sons, and by nightfall they would be driving away in their 1971 Plymouth with a $50 federal handout, heading for New York where the apples were just coming in.

Word travels quickly in the eastern migrant stream, and that's what brought the Robichauds to Maryland last month -- word that there was money to be made in the cucumber harvest. It was good for a while. One week the family Robichaud earned $300. They worked a few more days and then the cukes ran out.

They got along on food stamps, and the three boys went to the Wicomico County summer school for migrant children. But there was no more work, and it was time to hit the road again.

"You hope it's the best. You hope the market is good and you work very hard," Robichaud said, "but you don't get very far. . . . You travel so much you haven't got what you could call a friend."

You hope it's the best. . . .

All through the summer, not far from the glittering ocean playgrounds of Maryland, Virginia, and Delaware, an army of migrant field hands has been harvesting and handling some of the potatoes, tomatoes, cucumbers, beans and melons that grace the American dinner table. Local seasonal workers, although in short supply, join in the harvest, but the crop ripens so quickly and in such volume that the migrant's muscle is essential.

It is back-breaking stoop labor, but it is vital to the agricultural production system. Without it, the packing houses and the canneries would fail. The workers bend for a while, crawl for a while, then bend again, going down the endless rows from early morning to late afternoon, but it is a life of uncertainty and peril.

They work on a piece basis, or $3.80 an hour, whichever is higher, and when the crop is ample, a living wage can be earned. But the work is not constant, and the migrant's meager resources are quickly drained paying for rent and food, waiting for the rain to stop, waiting for the crop to be ready, traveling to the next field.

"If they could work eight hours a day, five days a week, they generally could make the minimum wage," said Al Perry, a Labor Department wage-and-hour official in the regional office at Atlanta. "A good worker can earn between $40 and $60 a day, but generally they are working two, four, six hours a day. They pay room and board and it's like 'Sixteen Tons' -- another day deeper in debt."

The migrants live in squalid little camps, sometimes five or six in a single room, in barracks or huts that lack basic sanitary facilities. Few water outlets, leaky roofs, broken screens, rank mattresses, clogged latrines, gang showers, open garbage cans. Disease and sickness -- parasites, endemic diarrhea, dermatitis, tuberculosis -- are widespread. Smelly trash, bugs, filth are all about. The camps are inspected and certified before the season opens, then generally not revisited by health inspectors after the migrants arrive.

Stores and dining sheds run by crew leaders keep many of the workers in unending debt. Stories of abuses by the crew leaders abound: cheating illiterate workers out of wages; overchanging for rent, food and illicit alcohol and drugs. Most of the migrants are caught in a compulsive cycle of promise, failure and more promise.

Farmers who own the camps and crew leaders who oversee them are wary of visitors. Lawyers and social workers are denied access. Last month growers expelled the Catholic nuns and migrant health services workers from the makeshift clinic they occupied on the big Westover camp south of here.

The Westover camp, once a World War II building pen for German prisoners, has acquired such notoriety that migrants from as far away as Texas refuse to stay there. The camp is operated by a dozen Somerset County growers, who include a county commissioner and a state delegate. The camp has spigots, but the best water comes from a nearby stream, where workers fill jars and pots to get drinking water. Maryland Gov. Harry Hughes is under pressure from his own Commission on Migratory and Seasonal Farm Labor to shut down Westover unless conditions there are improved dramatically.

From one camp to another, state to state, it becomes a trap. Ronald Robichaud, 37, was standing outside his room at a small camp talking about the trap he has been in since 1972, when he and his wife, who were broke and out of work in Oregon, became itinerant farm hands.

The camp operator, a crew leader named Bud Luther, euphemistically calls the ramshackle place a motel. A land-lettered sign on the front door of Luther's quarters and a cooler inside openly announce it is also a bar. He sells a 12-ounce can of beer for 75 cents, a 16-ounce can for $1.

Outside, idle migrants, mostly young black men, lazed under the trees, drinking their beer. A tape deck blared disco music. Crews were working elsewhere around Wiscomico County, but these men were waiting for calls to the fields. The calls that day never came, but as they waited, drank and ate, their debt to Bud Luther mounted, to be counted against the day they went back to work.

Only the lucky break free, Robichaud said. "You travel like me, you can't get references," he said. "Whenever I look for a job, they ask for references, and when I tell them I have been on the road, they are not interested in me. I want to get a security job in Florida and my wife can work as a waitress for a couple years, and then we will have some references."

The hope springs eternal, but hours later the Robichauds clambered into their $175 used car and drove north toward the apple orchards of central New York. Just need to earn enough money to get back to Florida, in time for the winter citrus, to get their feet back on the ground, Robichaud said.

Upward of 6,000 migrants (no one has accurate figures) have swarmed across the Delmarva Peninsula this summer, as they do every summer in their northerly pereginations, working to stock the American vegetable bin. In many ways they are outcasts in a land of plenty, yet essential to its comfort.

They are black, white and brown Americans; recently arrived black Haitian boat people who are new to exploitation American-style; Mexicans who came here illegally at great cost and risk to vanish into the underground of the eastern migrant stream, which stretches up the Atlantic seaboard from Florida to the Canadian border.

Another stream courses up through the Midwest from Texas; a third arches from Texas to Arizona, California and the Pacific Northwest. The streams are populated by an estimated 800,000 migrants, who join another 1 million or so seasonal workers from nearby communities in the fields and orchards.

The streams keep moving, south to north and back again through each season. As autumn approaches, the eastern stream flows out of Delmarva into New York for potatoes and apples. And more workers flood onto the fruited inland hillsides of Virginia, Maryland and West Virginia to pick the peaches and apples that will be the jam on tomorrow's toast and the filling of the pie.

Despite the abjectness of most of the labor camps, despite the haplessness and frustration of the workers, even the harshest critics of the migrant system concede there has been some change for the better during the past 20 years. Federal wage-and-hour laws have been put in place. Federally funded health, legal-aid and educational programs are available. Crew leaders, known formally as farm labor contractors, must register with the government and maintain records.

But abuses persist, and the cycle of deprivation and undereducation spans generations. An undermanned Department of Labor wage-and-hour enforcement branch must play interstate cat-and-mouse with crew leaders who are constantly on the move. Complex regulations delay swift application of penalties. State and local politics, at least along the Delmarva Peninsula, further complicate the mix. Farmers complain continually about "harassment" by health and safety enforcers.

Philip McCaleb of Belle Haven, Va., president of the potato and vegetable growers association in Northampton and Accomack counties, contends that farmers are caught in a difficult vise -- dependent on stoop labor, unable to set the prices for their harvest, required by government to do too much to improve conditions in the camps. But he also has come critical words for the farmers.

"I get extremely irritated at farmers bellyaching when some problems are of their own making," said McCaleb, who also doubles as chairman of Virginia's gubernatorial commission on migratory labor. "There is a lot of negative attitude about the people who work for them, and there is the issue of access to the camps -- farmers are very defensive about unknown parties coming to the camps."

Through it all, McCaleb and other growers on the Eastern Shore worry about the future of the produce industry. For large farmers, it is easier and more convient to abandon vegetables and turn to less risky corn and soybeans, which can be worked without stoop labor.

"The Eastern Shore is going out of vegetables largely because of the labor situation," McCaleb said. "The shore is ideally suited for vegetables, and we have a tremendous competitive advantage over growers in the West, but what concerns me is that growers in Virginia are being forced out because of a lack of capable labor and the constant burden of the regulators."

Farther north in Maryland, Charles Bruce of Mount Vernon, head of the Somerset County growers group, complains equally about the pressure of federal regulations and the uncertaintes of weather, labor and farm markets.

He concedes that "migrants have been abused and they will continue to be abused," but he adds: "They are doing what they want to do. It is a way of life for some of them, who have been coming back here every year since 1953."

Says Dennett Butler, a tomato grower from Shelltown, Md., who also is a Somerset County commissioner: "We are getting less and less truck crops around here because we can't be assured of a labor supply. There has to be guaranted housing. It is not only the harassment of regulation, but it is getting expensive. It cost me $4,000 to open my part of the Westover camp this year. Tomatoes, cucumbers, watermelons . . . somebody's got to grow them and everybody loves to eat them."

Somebody also has to pick them, and while it may be a "way of life" that Bruce and others talk about, it doesn't mean that all migrants are reconciled to it. Many, like Ronald Robichaud, desperately want out.Somed make it, but most don't.

The impermanence of the work is part of the problem. Even if he wants to put down roots, the migrant is never in any place long enough to establish himself. He is here today and gone tomorrow, usually working and living in fields far from easy view, with no political or economic clout to bring himself attention and not accustomed to challenging the authorities to claim what the law assures him.

Sister Regina Hudson, a migrant health nurse at Nassawadox, Va., expressed it this way: "Migrants are at the bottom of the totem pole. Nobody wants to deal with them. They come into an area all at once, then they go away. The grower doesn't want to see where they live, or know where they come from, or have people write about this. The farmer deals with the crew leader -- and that's where the bondage comes in."

Pauline James sees this from the perspective of a migrant who broke from the stream. She now counsels workers, helps them locate jobs (few are available around here) and funnels social services to them as director of the Exmore, Va., office of the Migrant and Seasonal Farmworkers Association (MSFA), a federally financed organization that covers six Atlantic Coast farm states.

"Every year the situation around here seem to get worse," she said recently. "This Eastern Shore is a desolate place for the migrant. The growers don't want anyone coming in and changing their 300-year situation. The old prejudices are here; nobody is changing. Nobody accepts these workers as human beings. Until people realize they have hopes and dreams -- and they they are human, too -- there will be no change."

In a sense, Pauline James is wrong. Change is coming, but it is not the kind of change she wants.

The Reagan administration's budget reductions threaten the legal services program that looks after migrants' interests and presses the Department of Labor to enforce job and wage-protection rules. The migrant health services program, doing work that can only be called life-saving, will be scaled down. the labor-contractor law fixing basic wage and living guarantees for the workers, through regulation of farmers and crew chiefs, is being rewritten by the administration for submission to Congress.

Such a prospect is not comforting to Beatrice Rivera, another former migrant who now is on the staff of the legal aid clinic 70 miles south of here at Belle Haven.

"Services are a lot better now than when I was in the stream," she said. "But the housing is no better. Some camps look like pigpens, although they have running water now. Mattresses are filthy. Children get sick. We have plenty of laws on the books, but the problem is having them enforced.

"Sometimes I wonder if they care at the top in Washington. I can't believe they couldn't stop this. They've got to admit they have failed -- all this money didn't get wasted at one time. It's been happening all along, and I ask why they didn't stop it.

"I was better off when I didn't know how things worked," she said. "I sit down and drive myself crazy over it, and I can't come up with an answer. I think it's because no one cares."