IT MAY BE IRREVERENT to say it, but the productivity revolution that has made American farmers the most efficient in the world has spoiled some of them. It has made others rigid. And, yes, it has even citified them. Some, even in the face of ailure, refuse o change their ways, and they pay a dear price for it in these days that demand diversification and new ideas. Others have become just plain slothful.

The same, of course, could be said for business executives, politicians, professionals, blue-collar workers. Perhaps this only certifies that farmers have come full bore into the late- 20th century. But they are not as unique as they would like the world to believe.

These farmers are a marvel of history. Their methods are copied; their success envied worldwide. Their mechanical and chemical victories are unsurpassed: An hour of farm work today produces 14 times as much as it did in 1920; the farmer now feeds 78 people, compared to maybe half a dozen back then.

All that is well and good, but something else is happening out there. The talk in rural America these days is all about hard times, and much of it is true. Many farmers are at their wit's end. Gloom shrouds the countryside. Yet farmers would just as soon the world didn't know that the gritty age of "American Gothic," Grant Wood's depiction of the stark farm couple with the pitchfork, is gone.

If "American Gothic" means simple, austere folk scratching a living from the soil as the embodiment of the agrarian ethic, it is more wistful past than reality.

An itinerant reporter's notebooks yield up telling views from this album of toil and plenty, suggesting just how far we may have come from "American Gothic:"

Snapshot: A bunch of farmers in rural Mississippi were drowning their sorrows in beer one night, despairing over tough times in the country, lamenting how a man could no longer count on soybeans and cotton for a living.

A visitor suggested alternative crops to get the cash-flow going. Asparagus or some other specialty crop seemed a natural. Big markets in Memphis and Jackson lay only several hours away. There was no shortage of farm labor or good growing weather. Why bring asparagus from California? But the farmers' reaction was instant. Asparagus was laughed out of the room. "I just couldn't do it," said one of them. "Those old beans are in my blood."

Snapshot: Some big-scale Ohio corn, wheat and soybean farmers were sitting around a coffee shop in Pickaway County, talking about their own depression: Heavy debt, slumping prices, escalating operating costs, heartless bankers.

Well, the visitor opined, at least there's a garden to fall back on. Good fresh vegetables and fruits. Keep the family in food year-around. Cascades of laughter drowned this naivete. "Nobody keeps a garden around here," one of the farmers said. "We're just too busy. We buy our food in a supermarket, just like you do."

Snapshot: An Iowa cattleman, a wise steward who religiously rotated his crops to invigorate his land and stop erosion, was talking about his Cass County neighbors. "In my part of the county, nobody raises cattle anymore," he said. "They all want to play golf on Thursday at the country club, rub elbows with the doctors and lawyers. They can't do that and raise stock. We've got three main crops here . . . corn, beans and Florida."

Snapshot: A large farmer from the Mississippi Delta was complaining about federal farm-support programs that propped up inefficient neighbors and made him less competitive. He owned vacation homes in Spain and Mexico. Another, bitterly going broke on depressed soybean prices, offered to fly a reporter 90 miles in his two-engine plane to verify his story with an economist.

Snapshot: In Kansas, a wheat farmer who diversified to supplement his income found it was more work than he had bargained for. He planted an acre of strawberries, which required something like 100 hours of labor per year to maintain. His wheat took an annual average of less than three hours labor per acre. The berries produced far more income than the wheat, but even at that the farmer was having some second thoughts.

Snapshot: A county agent from Woodstock, Vt., shook his head in some wonderment as he talked about dairy farmers in his area. "These dairy farmers have never known a 9-to-5 existence," he said, "but the trend in New England is for more and more of them to hire milkers. That's what farmers over 45 years of age want -- a hired milker, a guy who works about six hours a day. All he does is go around and attach the milking machines to the cows' udders."

These snapshots reflect a sense of the changing attitudes abetted by the mechanization and commercialization of American agriculture. Big, expensive machines -- behemoths like a 640-horsepower tractor, a 120-foot disk -- have taken the back-bending toil out of farming. Herbicides have replaced the hoe. Pesticides have helped the farmer forget the classical land-rotation techniques and natural approaches that controlled bugs. Synthetic fertilizers have lessened a farmer's need to keep the livestock that produced the manure that replenished the soil.

On top of that, a dozen straight years of rising grain exports (two of every five acres produces for export) and attractive prices pushed more and more farmers away from diversified farming and into an easier system emphasizing a single crop. They heeded a secretary of agriculture, Earl Butz, who told them in the 1970s to plow up the pastures and plant fencerow to fencerow. They listened to county agents who said the same thing. They read the farm magazines that said bigger, more mechanized farms were the wave of tomorrow.

Well, in a sense, tomorrow has arrived and it's not quite what these farmers bargained for. Prices of many basic commodities are below the cost of production. There is so much excess grain that the Reagan administration is running a land-diversion program that could idle more than 80 million acres this year. Exports are in a second straight year of serious decline. Farmers who leveraged themselves heavily in the 1970s to cash in on the boom are in big trouble.

What we are left with is a massive farm-production complex that in every sense has turned many farmers into big businessmen, yet stifled their general ability to roll with the uncertain punch of markets and weather. By some calculation, about 70 percent of our food is supplied by as few as 250,000 farmers -- the biggest of the big. They use computers in their offices and on their tractors. They play the futures markets. They hire accountants and subscribe to sophisticated magazines on marketing. They travel overseas on tax-deductible agricultural tours. They go to conventions in Hawaii, California, Florida and other outposts of affluence. They send their kids to college. Many of them fly airplanes, tour in recreational vehicles, pilot their own motorboats.

"Farm Futures," a slick marketing magazine published by a Wisconsin firm that also peddles an agricultural computer system, reckons that less than a 10th of the nation's estimated 2.4 million farmers control 57 percent of all the corn acreage, 60 percent of the soybeans, 71 percent of the wheat and 85 percent of the cotton.

The magazine's June issue, in an arbitrary ranking of the 100 "best managed" farms, found their average real growth of assets in the last five years was $1 million, average assets were nearly $3 million, 41 percent of them used computers and only 38 percent raised livestock. These "best" farms got $2 back for every dollar of operating expenses, compared to a Department of Agriculture calculation of $1.21 for all farms.

Whatever this is, it is not American Gothic. The changing nature of the farming industry, so swift and so dramatic, is underscored in newspapers from around the che ountry. The "news" these days often is about the growing phenomenon of families returning to the land and attempting to make their lives from it, much as their far-distant forebearers did. They are regarded with the cautious deference the press always reserves for oddballs.

Dr. Wayne D. Rasmussen, the historian at the Department of Agriculture, has observed these trends since he came here in 1937 from Montana, where he grew up on a ranch. "Ten years ago, I was on some Iowa farms and I ran into this: no chickens, no milk cows, no gardens. You begin to wonder about what is happening. But I suppose that farmers are caught up in the same ideologies as the rest of us -- that they ought to be able to earn a living from 40 hours of work, send their children to college."

"A few years ago a colleague and I did an unscientific survey. We talked to a lot of farmers about the agrarian ethic and the feeling that farmers are indeed different from other people. A lot of them felt that they were in an unappreciated business, but almost without exception, there still was some of this agrarian ethic left; a feeling that they were different, that they provided a valuable function and were not appreciated."

Farm lobbyists have known how to play on that theme in their dealings with the U.S. Congress, where their appeals are swathed in the romantic wraps of the small family farm -- the old American Gothic line, that is. The classic example, of course, has to be the federal dairy price support program, which now costs taxpayers more than $2 billion a year just to pay for the surplus nonfat dry milk, butter and cheese that cram government warehouses.

For all the fiscal nonsense that implies, Congress still cannot bring itself to cutting back the program in a serious way. There really is no argument that dairy farming and ranching are the toughest parts of agriculture. Dairymen and ranchers are on call 24 hours a day, every day of the week, either for milking or ministering to the ailing and the newly born. And the big dairy cooperatives learned long ago that political campaign money was the easy way to a legislator's heart.

But they knew something else: Congress is loathe to attack an industry that in many ways embodies the respect that members have for hard work and the seven-day week. Dairying, as one legislative aide put it, "is very, very demanding. . . . It fits the congressional image of the family farm. That idyllic family idea. A place with jobs that kids can do. They can't bring themselves to cutting that one back, especially when they know that so much of the rest of agriculture has changed."

In these times and this atmosphere, it seems entirely appropriate that the secretary of agriculture, the symbolic No. 1 farmer, would be a man like John R. Block, operator of a huge hog farm in Illinois. He is an exemplar end product of the farming revolution, a skilled farmer whose holdings keep expanding. He is as much a businessman as a tiller of soil -- a farmer who went to college (West Point) and sent his kids through school; a farmer who runs to keep in shape and competes in the Boston Marathon. He also has time to be a political activist and public- office holder. And you won't find him in the garden, mucking around in the spinach. He is a tad defensive, as one might expect, about the suggestion that the work ethic has changed on American farms.

"It's not the work ethic, it's specialization," Block said recently. "We are still in family farming, but it goes in a different direction. When I was young, there was one family on our farm. Now there are three generations, plus our helpers and their families. . . . If you find a farmer without a garden, it is that he feels his time is better spent on raising hogs or his specialty."

The secretary's wife put an interesting footnote to all this, maybe saying more about American farming, 1983, than she intended. In an interview with The Baltimore Sun, she talked about her little vegetable garden in Washington, where she is required to use organic methods (Secretary Block once called organic farming research "a dead end.") Mrs. Block told The Sun she was going to put in string beans, but the First Farmer wasn't encouraging.

"Buy them." she quoted him as saying. "It takes too long to pick them."