The forecast says 2009 income will reach $71.2 billion with the USDA attributing the drop to lower prices. However, the agency said prices will remain above the 10-year average.
Agriculture secretary Tom Vilsack said it is common to see a slippage after a strong year like farmers saw in 2008, but said there are still reasons to be anxious.
"We're obviously concerned," said Vilsack. "There are a number of producers that are stressed, and we're in the process of determining what assistance we can provide."
Despite the 20 percent fall-off, the net farm income expectation would result in the fifth largest on record, according to the USDA.
Vilsack said the USDA plans to provide additional credit to struggling dairy farmers across the country who are suffering from a dramatic drop in milk prices.
Earlier this week, a group of U.S. senators sent a letter to Vilsack urging the USDA to assist dairy farmers who were struck with they called a "crisis."
