On screen and off, the star of 'Country' leads farm crusade

She swept in looking more like a congresswoman than a movie star - Jessica Lange, who's gone from an Oscar award for ''Tootsie'' to producing a movie that's as real as shucked corn.

The movie is ''Country,'' a searing feature film about the plight of the family farm in the United States which has the authentic ring of a documentary. And Ms. Lange is out pitching it like hay: This day she steps up to the microphone of the National Press Club, with four television cameras pulsing, to tell why this film had to be made.

''Wasn't she the blonde in King Kong's fist?'' asks a guy at one press table. Yes, she was, but there's no trace of the ''King Kong'' starlet in this woman, who's wearing no visible makeup, her straight, wheat-colored hair falling nearly to the shoulders of a tailored black jacket, worn with a plain white blouse and black vest. She grips the mike purposefully and tells how it all began: ''When I was working in Los Angeles I went out to pick up the morning paper, and it was a slow day, a Saturday morning, and the Los Angeles Times had a picture on the front page of a farm family from London, Ohio, who were witnessing a foreclosure sale of their family farm.

''And there was something about the picture that struck me so deeply on an emotional level ... the picture was taken at the height of a no-sale foreclosure protest. ... The women (a farm wife and her mother) were filled with rage, and their anger was so obvious - they were striking out; you could see it in their faces and gestures.

''The father, on the other hand, was in a state of almost bewilderment. ... Of course, you can read a lot into a picture, but it looked as though he didn't fully understand what was happening to him at that moment.''

Lange, who grew up in rural Minnesota, says she heard stories from her father about the Great Depression and the loss of the family farm in the '30s. One of her homes today is a 120-acre farm in Cloquet, Minn., where she was born.

''In recent years when I've gone back to Minnesota, I saw (that) people really were in the depths of a depression. They refer to this time as being even tougher than the Great Depression of the '30s.'' She produced and starred in ''Country,'' she says, because ''once people are touched emotionally, that's the best way to get them to react or to act.'' The result is her new $10 million film, which took 60 days to shoot in Iowa.

Sharing the platform with her was a spokesman for Rural America, a nonprofit advocacy organization for the rural poor that served as technical adviser for the film and provided key source material. Its spokesman, Dave Ostendorf, pointed out that nationally the US has more than $216 billion in agricultural debt load today. Iowa, where ''Country'' was shot, has more than $17 billion. The $600 million to $700 million promised by both political parties today for debt restructuring, Mr. Ostendorf said, is not adequate to solve the problem. Meanwhile, an ABC World News survey indicates that 100,000 family farmers will be forced out of business this year. The rural population has been eroding since World War I, when it was 25 to 30 percent. Today the farm population is down to 2 to 3 percent.

''This land has been in my family for over 100 years,'' says Lange as Jewell Ivy, fighting to keep her 2,500-acre farm from foreclosure. The Ivy family has just been told by the Farmers Home Administration (FHA) that it has 30 days to pay off thousands in government debt or face a forced auction at the end of the month. The Ivys have not been profligate with their money; their family of five (plus her father) has been living on $9,000 a year (below the poverty level), plowing the rest back into repaying their loans and keeping the farm going. At 73 cents a bushel, the corn is costing more to grow than they can get for it at harvest time. Farmers like the Ivys are going broke because they can't make a profit.

But ''Country'' is not some grim documentary, it is a trenchant drama about a farm family, based on those farmers Lange interviewed across Iowa as she researched her film. As Jewell Ivy, Lange portrays a dauntless farm wife and mother who faces the storms that would blow their life away: the twister that flattens their crop and nearly kills their young son; the financial pressures that split her marriage and drive her husband (Sam Shepard) toward alcoholism; the foreclosure auction itself, in which she leads a ''no sale'' strike among farm neighbors defying government policy.

Lange's performance as the indomitable Jewell Ivy is in a league with Sally Field's textile-union organizer, ''Norma Rae,'' Jane Fonda's reporter covering a nuclear plant meltdown in ''China Syndrome,'' and Meryl Streep's plutonium victim in ''Silkwood.'' Already there's talk about another Academy Award nomination for ''Country'' star Lange, who was also nominated for her title role in ''Frances'' the year she won an Oscar for ''Tootsie.'' And the film itself, under the direction of Richard Pearce, who did ''Heartland,'' is as memorable as one of Thomas Hart Benton's Midwest paintings, all big sky and flat farmland and lonely frame farmhouses.

Osterdorf of Rural America says the Ivys are symbolic of the thousands of farm families who are being squeezed. Many of those whose farms were foreclosed ''were not so-called poverty families.'' Speaking from Rural America's legal experience in helping such people, he said: ''I can't tell you how many families we worked with that had their farms paid for, and took a risk to get their daughters or sons in the operation, and are now going under. We're looking at farm families from their 20s to 70s. We've had families in our office in their 70s who would break down and cry because they're losing it all. And they didn't overexpand. They were caught in and victimized by the kind of economic situation we're in and the kind of policies this government is putting on us.''

Ostendorf says the FHA has lost 15,756 farm families across the US through ''force-out rates'' over the last three fiscal years. In Iowa the rate is high: 11,000 families. Last year, Rural America filed a class action suit against FHA for calling in loans and foreclosing without properly informing borrowers of their rights. A federal judge ruled in February that the agency must properly inform borrowers of their legal rights. But Ostendorf says the judge's ruling ''did not resolve the situation. Farmers have gotten a little more lead time and perhaps a little bit more opportunity to resolve their problems, but it has not stopped the FHA from foreclosing on people.''

On the subject of corporate agriculture or agribusinesses, which are taking over land once farmed by families, he says: ''I think what we're facing in this country with continuing takeover of the landed family farms is the continued concentration of control in the hands of fewer and fewer people. And that situation has to be stopped.'' Osterdorf recommends an immediate moratorium on all farm foreclosures nationwide, a better price and return of profit to agriculture, and debt restructuring to ease the load on family farms. ''I also think that we need support across the country for a major investigation by Congress of the Farmers Home Administration, the Farmers Credit Administration, and other federally related agencies that we believe are systematically engaged in eliminating farm families.''

From Henry Fonda in Steinbeck's ''The Grapes of Wrath'' to Edward R. Murrow's trailblazing documentary on migrant workers, ''Harvest of Shame,'' the land and those who work it has been one of the camera's most compelling social subjects. If ''Country's'' social impact is equal to its big box-office and critical acclaim, Lange and her film may be appearing before a congressional committee as well as at the Academy Awards this year.