U.S. crop exports took a significant dive this past week at a time when exports have historically accelerated. The reason? Massively slowed exports at Louisiana Gulf Coast terminals due to ongoing drought conditions slowing movement on the Mississippi River. Low water levels in the lower Mississippi River have led to the halting of grain barges on what is otherwise the nation’s largest grain shipping port.

The during-harvest timing presents an additional challenge. As farmers across the Corn Belt bring in fresh corn and soybean crops, they rely on river transportation to get their yields to the Gulf. USDA’s weekly report said just over 976,00 tonnes of corn, soybeans and wheat were inspected for export, the lowest for the first week of October in at least nine years and down a whopping 22% from the previous five-year average.

Read more on shipping pressures here.