USDA predicts net U.S. farm income will drop 38 percent this year to $55.9 billion.
That would be the lowest level in more than a decade, reflecting lower crop prices and softening dairy and hog markets.
Net farm income will decline to the lowest since 2002, just two years after it reached a record $123 billion in 2013.
The projected drop would mark the second consecutive decrease since 2013, driven in part by large corn and soybean crops and a projected 8.7 percent decline in crop receipts, according to a report by Dow Jones.
USDA said lower prices for milk, hogs, broiler chickens and cattle also have pressured farm incomes.
Corn futures have fallen near eight percent this year and have dropped 50 percent since the severe drought in 2012.