Over the last several weeks, drought-driven drops in water levels rivers in Argentina, Brazil, and Paraguay have forced barges to reduce capacities to avoid grounding, the U.S. Department of Agriculture said today.

These lighter barge loads have slowed the flow of corn, soybeans, soybean meal, and soybean oil to key export locations, the USDA said in its weekly Grain Transportation Report (GTR). In Paraguay, parts of the Paraná River (a major artery for soybean transport) have been closed to barge navigation since the beginning of April, the GTR said.

According to Bloomberg, free-on-board corn export prices in Argentina and Brazil for spot, 30 days forward and 60 days forward, are being quoted at record highs. Argentina and landlocked Paraguay depend more on barges than Brazil, which mostly relies on rail and truck for agricultural transportation. Supply disruptions from these key South American sources could shift global buyers to pull from U.S. stocks instead, the USDA said.