But global soyabean exports have doubled within the last decade based on rapid demand growth worldwide, and this has made room for other countries to build up export markets of their own. Argentina is also a traditional exporter of soyabeans, though it has recently been overtaken by neighbouring Paraguay and Canada.
Soybean exports are on the rise in nontraditional suppliers. USDA's 2018-19 world soyabean export target is 156 million tonnes, and removing Brazil, the United States and Argentina reveals some 18 million tonnes left on the balance sheet to be covered by other countries. That is about a third of the volume shipped by the United States in 2017-18.
Given the trade conflict between No. 2 supplier the United States and top buyer China, many market participants wonder where the other options may lie for Chinese crushers and how much US soya business may be siphoned away should a trade war resolution fail to arrive quickly.
The US Department of Agriculture predicts US exports to reach 51.7 million tonnes (1.9 billion bushels) in 2018-19, but some analysts doubt this is possible even with China's recent return to the US market, as the total purchases remain relatively small.
In an email message last week, a USDA representative said the agency does not forecast trade shares, so it is unclear just how much China factors in to the full US program. However, USDA did say in its reports that US soyabean business to non-China destinations is expected to be much heavier than in prior years.
USDA data suggests China will account for 59 percent of global soyabean imports in 2018-19, its smallest share in eight years. This partially reflects the rising protein demand and crushing infrastructures worldwide, reminding market participants there is a growing need for soyabeans in countries other than China.
Aside from the European Union which is expected to import nearly 16 million tonnes of soyabeans this year, some 13 countries are scheduled to take in more than 2 million tonnes in 2018-19.
Argentina is traditionally the third-largest exporter of raw soyabeans, though it will fall to No. 5 in 2018-19 according to USDA's projections. The agency believes Argentina will be a victim of the US-China trade war, which will create stiff competition with Brazil and potentially the United States if supplies there are cheaper.
USDA last week slashed Argentina's export forecast to 5 million tonnes from the previous forecast of 8 million.
But Argentina's Rosario grains exchange predicts a drastically different outcome, recently saying this year's exports could reach a record-high 14 million tonnes, a sharp rebound from last year's 4 million. However, this scenario appears to rely on the continuation of trade conflicts between the United States and China.
USDA data suggests that following its historic drought a year ago, Argentina was the sixth-largest exporter of soyabeans in 2017-18, following Paraguay, Canada and Ukraine.
Aside from the traditional three exporters, there are four other countries that are shipping notable soyabean volumes: Paraguay, Canada, Ukraine and Uruguay. Together, USDA predicts these countries will export nearly 17 million tonnes of soyabeans in 2018-19.
Of those four, Uruguay has the strongest reliance on China. According to the country's agriculture ministry, Uruguay shipped 2.7 million tonnes of soyabeans to China in 2017, which was about 82 percent of the total. USDA has pegged Uruguay's soyabean exports at 2.4 million tonnes in 2018-19.
China also dominates Canada's soyabean export market, and increasingly so in recent years. Four years ago, about 21 percent of Canada's beans were sent to China, but that share rose to 44 percent two years later. USDA predicts Canada will ship a record 5.3 million tonnes of soyabeans in 2018-19, making it the fourth-largest supplier.
Some market participants assume Canada's bean exports are largely made up of cheap US beans, but data does not back that up. While nearly 80 percent of Canada's soyabean imports do come from its southern neighbour, the total imported volume is only one-tenth of the total export volume.
USDA has slated Paraguay as the third-largest soyabean exporter for the second year in a row, but the landlocked South American country should not compete for trade business with China, at least not directly.
Paraguayan soyabeans often have higher protein levels ideal for blending with lower-protein beans in foreign crush operations. Therefore, Argentina has recently become a major importer of its northern neighbour's soyabeans. Other typical markets for Paraguay include Turkey, Russia and the European Union.
USDA sees Paraguay's exports in 2018-19 falling to 5.8 million tonnes from last year's high of 6.2 million based on lower exportable supplies.
Ukraine's primary oilseed is sunflower, but soyabeans are on a steady rise in the country, and USDA predicts its soya exports will reach a record 3.1 million tonnes this year. In the last couple of years, the main destinations for Ukrainian soyabeans have been Turkey, Iran, and Egypt. Various European Union countries also partake, particularly Greece and Italy.