They look like migrant farm workers, they work like migrant farm workers, they live and get paid like migrant farm workers, but in some parts of the Midwest they are no longer being called migrant farm workers.

They're being called sharecroppers, a linguistic nicety that allows the farmers who employ them to avoid paying minimum wages and to escape Social Security, unemployment and workmen's compensation contributions.

This semantic gambit has been reported in Ohio, Michigan, Indiana and Wisconsin, and now, after a four-year wait, a U.S. Department of Labor suit attempting to halt the practice is scheduled to go to trial in July.

In the view of migrant-law attorneys watching the case, the outcome of the government's suit against Jerry Brandel Farms of Hart, Mich., will determine whether the practice is stopped or whether it spreads to other parts of the country.

Said Ron Kirshenheiter of the Michigan Migrant Legal Action Program: "This case involves cucumbers, but I have another case involving cherries in which the same principle is at stake. If the Brandel case stands, we don't see why it couldn't spread. A lot of farmers are sitting and watching this one closely."

Brandel has been charged with violation of federal child-labor and record-keeping laws. His defense is that the migrant laborers actually were sharecroppers, or independent contractors, because they worked for a percentage of the sale price of cucumbers they picked.

As self-employed workers, the sharecroppers or independent contractors would be responsible for their own contributions to federal labor protection programs.

Seven national and regional farm worker advocacy organizations joined last week in filing a lengthy brief supporting the federal position in the Brandel case in the western district of Michigan.

"It is especially important in this year of cutbacks in social programs and reduced enforcement of protective programs for low-income people that the sharefarmer scheme be exposed and stopped," the groups said.

Their brief argued that the sharecropper "ploy" deprives migrants of the minimum wage, unemployment and workers compensation, and the Social Security program, while removing children from the protections of child-labor and pesticide-control laws.

Kirshenheiter and migrant attorneys here said that the controversial practice apparently has been used most widely in the cucumber harvest, where picking rates are set according to the size of the vegetable, which is ticketed for pickle factories.

Typically, they say, a cucumber grower offers the worker a "share" of the crop, theoretically an incentive to pick faster and according to demand for various sizes, although in fact the worker has no stake in the crop or the land.

Even though the worker is given a "share" of the crop, he has no control over its pricing or marketing. Price is determined beforehand by the grower and the packer who purchases the cucumber.

"The tests for determining whether a person is an employe or an independent contractor include whether the worker has the right to control the work, whether the worker has the opportunity to make a profit or loss, whether the worker has an investment in work tools and whether a high level of skill is required to perform the job," the advocacy groups' brief said. "Migrants generally would not satisfy any of these tests."

Kirshenheiter and Charles Horowitz, an attorney with the Migrant Legal Action Program here, said that another similar sharecropper case litigated in Ohio had produced confusing results--a judge held the practice was acceptable but later altered his position.

They noted that the Wisconsin attorney general, in a separate opinion calling sharecropper designations there invalid, held that farmers apparently were seeking to avoid requirements of state and federal worker protective laws.