Washington: China reached into the US heartland in its escalating trade war over President Donald Trump's tariffs, using an advertising supplement in Iowa's largest newspaper to highlight the impact on the state's soybean farmers as "the fruit of a president's folly.''

An American soybean farm. Credit:Bloomberg

The four-page section in Sunday's Des Moines Register, which carried the label "paid for and prepared solely by China Daily, an official publication of the People's Republic of China," featured such articles as one outlining how the trade dispute is forcing Chinese importers to turn to South America instead of the US for soybeans.

The advertising targets a state critical to Trump and Republicans as the trade war between the world's two largest economies intensifies. The US is imposing tariffs on an additional $US200 billion worth of Chinese imports starting Monday, on top of the $US50 billion in goods already hit with tariffs. Meanwhile, $US110 billion of goods from the US will become subject to Chinese retaliatory tariffs around the same time.

"As the largest importer of US soybeans, China is a vital and robust market we cannot afford to lose,'' the supplement quotes Davie Stephens, vice president of the American Soybean Association and a Kentucky soybean grower, saying in a statement.