(Adds details, analyst’s comments, chart and milestones) BEIJING, April 20 (Reuters) - China’s March soybean imports from Brazil plunged as rain delayed some shipments from the world’s top exporter, but U.S. bean imports rocketed more than fourfold as delayed cargoes arrived, hitting the highest monthly total since December 2016. The world’s biggest buyer of soybeans imported 315,334 tonnes from Brazil in March, down 85% from 2.1 million tonnes a year earlier, data from the General Administration of Custom showed on Tuesday. The Brazilian imports were the lowest since January 2017, according to Reuters records of customs data. More than offsetting that slide, China imported 7.18 million tonnes of soybeans from the United States in March, up 320% from 1.71 million tonnes in the previous year. Tuesday’s data provided the first breakdown of imports by origin since China published data earlier this month showing overall imports of soybeans last month climbed 82% to 7.77 million tonnes. “A lot of it seemed to come down to some delays affecting the timing of when U.S. shipments arrived,” said Darin Friedrichs, senior analyst at StoneX. “Some of the cargoes could have arrived earlier, but didn’t actually get offloaded until March.” China had stepped up purchases of soybeans and other U.S. farm produce after the two sides signed an initial trade deal in January last year. But buyers of the oilseed have turned to the United States more than usual in 2021, as rains in Brazil slowed the harvest there and delayed exports. Chinese crushers bring in soybeans to crush into soymeal to feed livestock and for cooking oil. They had previously ramped up buying of soybeans amid expectations of healthy demand from the country’s fast-recovering hog herd. But a severe wave of African swine fever in recent months has wiped out at least 20% of the breeding herd in northern China, some estimates show, reducing soymeal demand. Increased use of wheat in animal feed has also curbed soymeal demand, analysts and traders say.