SAO PAULO, Dec 18 (Reuters) - Brazil could lose $10 billion per year in farm exports to China if a recent Sino-U.S. trade deal is implemented as proposed, according to a study by Brazilian research center and business school Insper published on Wednesday by local newspaper Folha de S.Paulo.

Brazil-China trade could return to pre-trade war levels, erasing some of the gains seen, particularly last year, said Marcos Jank, a former BRF SA executive in Asia and agricultural trade expert, who coordinated the study.

Brazilian farm exports to China surged to $35.4 billion in 2018 from $26.6 billion the year before, as farmers and meatpackers took advantage of higher tariffs on U.S. agricultural products to boost deals, the report said.

In that period, U.S. farm exports to China dropped to $13.2 billion from $24 billion.

“The first thing that is likely to happen is a rebalancing on soy trade,” Jank told the newspaper.

Cotton and poultry are among other products that could be affected, the study said.

Brazil sold $1.1 billion in poultry to China in 2018, while U.S. sales stood at only around $100 million.

In cotton trade, American farmers had long dominated the Chinese market, but Brazilian producers managed to catch up in 2019, helped by the tariffs and higher production.

Insper projects U.S. cotton sales to China this year at $714 million and Brazil sales at $711 million. (Reporting by Marcelo Teixeira; editing by Jonathan Oatis)