The first US government forecast incorporating the agricultural fallout from its trade war with China has come to a firm conclusion on soyabeans: China will import less, American farmers will lose business and Brazil will be a beneficiary.

Beijing last week increased duties on imported US soyabeans, cotton and other products by 25 percentage points in response to tariffs on Chinese goods imposed by Donald Trump’s administration. Soyabeans are the US’s largest agricultural export to China and are grown in rural states that mainly voted for Mr Trump.

As the top soyabean importer, accounting for more than 60 per cent of global trade, China’s move has rattled markets. Soyabean futures have slumped to levels at which many US farmers will lose money without federal assistance.

The US Department of Agriculture, in monthly supply and demand estimates published on Thursday, cut its forecast for China’s soyabean imports from 103million to 95million tonnes in the coming marketing year, reduced its outlook for US soyabean exports by nearly 11 per cent from 62.3million to 55.5million tonnes and raised its estimate of Brazilian exports from 73million to 75million tonnes, a record high.

The new Chinese tariffs raised duties on US soyabeans from 13 per cent to 38 per cent, according to the US Soybean Export Council. The levy began redirecting trade flows even before taking effect on July 6.

Marcel Smits, chief financial officer of Cargill, the world’s largest agricultural trader, said in an interview that China has been cancelling purchases of US soyabeans and non-Chinese customers have been attracted to the US.

“What is happening in the market is everyone is positioning in order to optimise their flows relative to the current tariff and pricing structures,” Mr Smits said.