Traders said US soybean prices were high compared to values in Brazil, where farmers are already harvesting early maturing varieties and small amounts are becoming ready for shipment to buyers in early February.
"Shipments are going to be earlier than usual," said grains analyst Dan Basse, president of research firm AgResource Co.
Traders said Brazilian soybeans for March shipment were quoted at 40 cents a bushel premium the CBOT March on a FOB basis, which excludes shipping costs. That compared with premiums of 69 to 78 cents a bushel from the US Gulf.
Based on those prices, importers would pay about $85,000 less for a standard 60,000-tonne Panamax cargo from Brazil than from the United States for March shipment, traders said.
Basse said China's demand for US soy was surprisingly strong despite its processors defaulting on about $300 million worth of soy purchases mostly from Brazil last year following a credit squeeze in the Asian country.
"I've got them at 10 million tonnes and it could go up to 10.5 million," he said, referring to Chinese imports from the United States. "Early on, we thought China was going to take 8.0-8.2 million tonnes," he added.
According to USDA data, China has purchased 9.64 million tonnes of US soybeans since the marketing season began on September 1. Of the amount, the country has already taken delivery of 8.30 million tonnes.
A trader said that although Chinese processors have begun buying soybeans from Brazil, there was talk of concerns among some of them over getting safety certificates from Chinese authorities for Brazil's genetically modified soy. China stopped accepting applications for the certificates - which are necessary to unload Brazil's genetically modified soy at Chinese ports - from the start of the year, but the issue was resolved this month after a meeting between Chinese and Brazilian officials.
"They haven't finalised it yet. With China, this could take longer than you think," said the trader, who does business with Chinese soy processors.
But major grain companies like Archer Daniels Midland Co, were forging ahead with their switch to South American soybeans.
ADM Senior Vice President Brian Peterson told a conference call with stocks analysts last Friday:
"Our Chinese and European soybean crushing operations will be shifting a significant portion of their origination of soybeans from North America to South America starting February." "We are expecting a large South American crop."