Contracting parties to the General Agreement on Tariffs and Trade (1947-94) could use quotas to limit imports of agricultural products from other countries. Under the Uruguay Round (1986-94), import quotas were replaced by tariffs (a process referred to as "tariffication"). Use diagrams to compare the welfare implications of an import quota versus an equivalent tariff on consumers, producers, and the government of the importing country. Use another diagram to show how welfare in the market for a substitute would be affected.