The U.S. has long been the world's largest soybean-producing country, but South America now appears to have supplanted it.as the global residual supplier. South American Soybean Crop Keeps Getting Larger USDA raised its forecast for the 2015 Argentine soybean crop on Tuesday from 57 MMT to 58.5 MMT. Now it seems that this is even too low as the Rosario Grains Exchange raised its forecast yesterday from 59 MMT to 59.6 MMT. It said that the higher estimate was based on farmers in the country's central growing area seeing yields at around 4 MT/hectare (59.5 bushels/acre). Because of this, the exchange is now forecasting the national average soybean yield at 3 MT/hectare (44.6 bushels/acre). Also, the Buenos Aires Grain Exchange predicted tod...