There was no evidence of any last-minute negotiations between US and Chinese officials, business sources in Washington and Beijing said.
Trump's tariffs are the result of an investigation by the administration into the theft of United States intellectual property by Chinese firms and their government.
American Soybean Association President John Heisdorffer said the retaliatory tariffs will "sting" his industry.
Chinese buying of soybeans has ground nearly to a halt ahead of the duties, while Chinese farmers worry the penalties and tighter supplies will drive up costs, squeeze margins and ultimately inflate retail prices of pork, the country's top-selling meat.
China's tariffs, on the other hand, will hit agricultural products like soybeans and pork.
"Our commodity market and job market are relatively flexible, and our foreign-related economic sectors' ability to make flexible adjustment is more prominent", said Guo Shuqing, chairman of the China Banking and Insurance Regulatory Commission, in an interview Thursday with the Chinese financial newspaper Financial News. -China trade involves parts and supplies, rather than final goods - so the most immediate effect will be felt by the companies making the products, not the consumers finding them on store shelves.
Shares in Chinese markets took a beating in the run-up to the deadline, slipped further after passing, and pulled the Asian markets down. The Shanghai Composite index fell 1.1 per cent, after reaching more than a two-year low this week, while United States indices are expected to follow suit when they open later today. Beijing has announced reforms this year including ending limits on foreign ownership in its auto industry, but none directly addresses complaints that are fueling its conflict with Washington.
"In a gaggle aboard Air Force One Thursday, Trump all but confirmed that he was following through with his threats, ticking through the additional tariffs he planned to levy after the initial salvo kicked in: ".
After that, the hostilities could intensify: Trump said the United States is ready to target an additional $200 billion in Chinese imports - and then $US300 billion more - if Beijing does not yield to U.S. demands and continues to retaliate.
That would bring the total of targeted Chinese goods to potentially US$550 billion - more than the US$506 billion in goods that China actually shipped to the United States a year ago.
The U.S. also has irked some of its closest allies by hiking import duties on steel, aluminum and autos from Europe, Japan, Canada and Mexico. If the U.S.is determined to escalate conflicts with China, then so be it.
That came after President Trump warned that in the end, the US could target over $500 billion worth of Chinese goods - roughly the amount, in total, that the USA has imported from China a year ago.
"This is a potential concern for the outlook of corporate investment and consumption around world", Hui said. "But it is applying the brakes to a global economy that has less durable momentum than appears to be the case", Rob Carnell, chief economist at ING, said in a note to clients.
"The worldwide financial crisis, which ensured that we now act in the framework of the G-20, would never have been resolved so quickly, despite the pain, if we hadn't cooperated in a multilateral fashion in the spirit of comradeship", Merkel said on Wednesday.
The bank estimates that every $US100b of imports affected by the tariffs represents about 0.5 percent of global trade and 0.1 percent of global GDP. But after three rounds of negotiations between the two sides, including a Chinese pledge to significantly increase purchases of American products, Trump chose to go ahead with the tariffs.
There was no evidence of any last-minute negotiations between United States and Chinese officials, business sources in Washington and Beijing said.
The company wants customers to split the cost of the tariff hike, but few are willing, said Tong.