A meeting of agriculture ministers from 24 leading developed countries on Thursday andFriday in Paris could prove crucial in determining whether the Uruguay Round of international trade negotiations can be wrapped up by the April 15 deadline.

Of course, "crucial" meetings, like deadlines, have come and gone many times since the talks, sponsored by the Geneva-based General Agreement on Tariffs and Trade, began in Uruguay five and one-half years ago.Thus, no one is holding his breath in expectation that the talks will be concluded by the new deadline.

"I suspect it's unlikely that this process will be finalized before next year," said Steve McCoy, executive director of the North American Export Grain Association.

French Opposition

The main obstacle throughout the round has been the European Community's refusal to make steep cuts in its farm subsidies, largely

because of French opposition.

The unity's gone out of the community on agricultural issues. Britain, the Netherlands, Germany, Denmark and Italy appear ready to compromise, but France and Ireland have steadfastly resisted any measures that could harm their farmers.

This week's gathering represents the first agricultural ministerial meeting of the Organization for Economic Cooperation and Development since 1982.

Dunkel Formula

The focus is likely to be on the proposals by Arthur Dunkel, GATT's director general, for comprehensive reform.

The main elements in Mr. Dunkel's formula are as follows:

* A 20 percent cut in domestic supports.

* A 36 percent reduction in export subsidy payments.

* A 24 percent drop in the volume of subsidized exports.

The cuts would be made over a six-year period, starting in 1993. Mr. Dunkel also wants all farm import protection measures converted into tariffs and for these to be reduced by 36 percent between 1993 and 1999.

"There has to be an agreement relatively quickly," said Dan Amstutz, a former U.S. undersecretary of agriculture who led the U.S. negotiating team on farm issues during the Reagan administration.

But, he added, meeting the April 15 deadline becomes more and more difficult as each week passes.

Under the Dunkel formula for internal supports, nearly every U.S. commodity, except peanuts, would escape cuts in domestic subsidies because of previous reductions, according to Edward Madigan, agriculture secretary.

The United States would be required to cut export subsidies by some $350 million, while the EC would face more than $4 billion in export subsidy reductions, Mr. Madigan said.

Total EC subsidies for its farmers, including domestic support programs, range between $40 billion and $45 billion, according to another USDA official. U.S. subsidies range between $10 billion and $12 billion, he added.

Proposal Best Hope

U.S. officials consider the Dunkel proposal the best hope for wrapping up the farm talks.

"I would vote for it," Mr. Madigan told a group of state agriculture commissioners earlier this month.

Mr. Madigan said the GATT chief should call participants back to the negotiating table and ask for a straight up-or-down vote on the plan.

"I think it comes down to the Europeans," Mr. Madigan said. "Would they raise their hands and vote no?"

The USDA chief said even countries that don't like the Dunkel proposal ''would be pretty hard-pressed to vote no and kill" the GATT negotiations.

'Dangerously Slanted'

But Dominique Strauss-Kahn, France's minister of industry and international trade, recently charged that Mr. Dunkel's formula is "dangerously slanted" against the EC.

Louis Mermaz, France's agriculture minister, is especially opposed to any limits on the volume of subsidized exports. France is the EC's biggest grain- exporting nation, and its big farmers in the fertile Paris Basin can compete with U.S. exporters without subsidies.

The Europeans aren't the only ones holding up the negotiations. Japan and South Korea, with their adamant opposition to opening their rice markets to imports, haven't helped matters either.

Even if no accord is reached this spring, it is possible negotiators will agree to put the talks on hold until next year rather than run the risk of carrying on during a U.S. election campaign in which trade may be one of the hottest issues.

"After the elections, maybe something could happen that could lead to an agreement," said John Datt, executive director of the American Farm Bureau Federation's Washington office.