Belarus, trying to build up trading momentum after the collapse of a joint venture with Russia, plans to increase potash supplies to China, the world's biggest consumer of the crop nutrient, Belarus said on Friday.

Belarus' sales alliance with Russian potash giant Uralkali broke up in July, threatening to push down prices and causing an economic headache for Belarus, where potash exports account for 12 percent of state revenue.

The trading arm of state potash producer Belaruskali - Belarusian Potash Company (BPC) - said it had signed a three-year draft supply contract with China's Sinofert Holdings .

Sinofert, which is China's largest fertiliser supplier and distributor, confirmed the framework deal to Reuters.

The breakup of the alliance between Uralkali and Belaruskali has left North America's Canpotex Ltd, owned by Potash Corp , Mosaic Co and Agrium Inc, as the last global potash-trading partnership. Potash Corp expects Canpotex to sign a new contract with the Chinese firm in early 2014.

Attempts by Belaruskali and other producers to place additional volumes following the breakup could put further pressure on prices, Uralkali has said.

BPC declined to disclose volumes and prices of future supplies to Sinofert, although its representative Irina Savchenko told Reuters the contract would cover "a significant amount every year."

BPC plans to boost its sales by up to 100,000 tonnes month-on-month in October. China imports around 6 million tonnes of potash a year, more than 10 percent of global demand.

BPC did not say when it would sign the actual supply contract with Sinofert. Signing the memorandum "gives us reason to be confident that we will cooperate in the future," Savchenko said.