S. American 'soybean king' says region feeds world Argentina's Gustavo Grobocopatel, known as the "soybean king," is head of one of the most powerful agro-industrial groups in South America. His empire, Los Grobo, is the largest producer of wheat in Latin America, and deals not only in soy, grains and oilseeds, but also provides agri-input and technical assistance to farmers. Images and soundbites.