And although developing nations gained by persuading the rich world to cut agricultural production subsidies, poor African states could lose some of their existing preferential access to European and US markets.
German Economy Minister Wolfgang Clement said the 147-member World Trade Organisation (WTO) had grasped the opportunity and achieved "a substantial step forward in world trade talks".
French Agriculture Minister Herve Gaymard told France Info radio it was a good and balanced accord that "consolidates the European common agricultural policy and does not question the reforms decided a year ago".
For Britain, the world's fourth largest economy, Trade and Industry Minister Patricia Hewitt called the accord ... "a crucial step on the road to delivering a trade round that will benefit all of us, especially developing countries." Trading powerhouse China was more stinting in its praise.
"Generally speaking, the framework (agreement) is not bad, though the developing countries are not fully satisfied," the official Xinhua news agency quoted Sun Zhenyu, China's ambassador to the WTO, as saying.
The agreement holds out hope for a final pact that would cut tariffs on agricultural and industrial goods, slash farm subsidies in rich countries and make it easier for financial and service industry firms to work across borders.
It puts talks back on track after a bitter collapse nearly a year ago in Cancun, Mexico that pitted developing countries like Brazil and India against rich WTO members such as the United States and the European Union.
But Peter Draper, research fellow at the South African Institute for International Affairs, said Africa's cherished tariff-free quotas into the US and the European Union would be far less valuable if lower tariffs were given to all importers.
He was also sceptical about a deal struck between the United States and struggling West African cotton producers, which drops poor country demands to have cotton treated as a special issue, but gives the crop special importance within the farm chapter.
"I wonder how useful it will be? There are all sorts of nice terms like 'cotton is going to be treated expeditiously', but there was lots of similar language in the (1986-93) Uruguay round of talks that was never acted upon. I'm worried about it."
Environmental group Friends of the Earth criticised as "empty promises" the concessions made by Washington and Brussels on agriculture.
"The commitment to eliminate export subsidies credits is missing any substance as no end date is mentioned in the text," it said.
Japan, the world's second-largest economy and a major food importer, said that rather than an agreement being reached the deal meant negotiations were back on track.
Foreign Minister Yoriko Kawaguchi said: "It includes the elements needed to bring about a balanced final agreement, but at the same time allows for Japan to make its case on sensitive agricultural products at future negotiations, so I think we should rate it highly."
The powerful EU farm union, composed of the Committee of Agricultural Organisations in the European Union (COPA) and the General Confederation of Agricultural Co-operatives (COGECA), said the WTO deal protected EU agricultural policy and called on European authorities to make sure it stayed that way in future negotiations.
The union represents 11 million farmers and about 30,000 co-operatives in the EU.