STOver the years, as the world's trading nations gradually loweredtheir tariff walls, they erected an extensive -- and often ingenious --array of nontariff barriers to trade in order to protect their domestic industries from foreign competition.

The following is a list of the major ones and a summary of new trade agreements nearing completion in Geneva that seek to begin dismantling them:

Government subsidies.Government ownership or financial assistance to farmers and factories enables their products sold on foreign markets for less than unsubsidized products, thus providing a competitive advantage. Subsidies are used more widely abroad than in the United States. Direct export subsidies would be banned for industrial goods and for farm products that are used to displace other nation's exports or to undercut prices. Some relief is also provided for purely domestic subsidies, including mechanisms for dispute settlement and possible retaliation by importing countries.

Government procurement. Many countries, including the United States, give preference to home industries for purchase of goods by their governments. New procedures covering specifications, bidding and other practices, along with a dispute settlement mechanism, are designed to reduce these preferences. The United States figures this will open $26 billion in foreign markets and $12 billion in U.S. markets.

Safeguards. These are devices, such as quotas that trading nations use to impose theoretically temporary limits on imports that are threatening domestic industries. Quotas on specialty steel and negotiated limits on color television sets are an example of U.S. safeguards. Signatory nations would be required to observe a number of rules and conditions, including more openness and due process.

Product standards and licensing standards for admitting imported products are often arbitrary and open to manipulation, and licensing requirements are often so cumbersome that they effectively block imports. Separate codes on standards and licensing seek to simplify and standardize these procedures.

Customs valuations. The methods by which nations compute the value of an import vary widely and affect the amount of a duty payment. An example is the American Selling Price, pegged to U.S. prices rather than the value of the imported product. The code outlines uniform methods for valuation for all nations to use.

Commercial counterfeiting. Many nations "pirate" trademarks and trade names, principally of U.S. products, selling their products for less than the real thing. Negotiations are continuing on this one.

Other negotiations in various stages of completion cover a new agreement envisioning an international wheat reserve; consultative arrangements on feed grains, meat and dairy products; elimination of tariffs and reduction of nontariff barriers for aircraft, and machinery for future revisions in the General Agreements on Tariffs and Trade, the 32-year-old framework for trade negotiations under which the current talks were held.