WASHINGTON — The U.S. Department of Agriculture said sugar processors repaid $16.3 million in federal loans that were due by July 31. The U.S.D.A. spent $50.7 million buying sugar last month in order to drive domestic prices high enough for processors to pay back the loans.

U.S. sugar futures are down 10% this year, and falling prices are a threat to the government’s sugar program that provides loans, price supports and import restrictions for sugar processors.

Approximately $457 million in federal sugar loans are due at the end of August and September. If the processors default on the loans, they will pay back the government with sugar instead of cash.