DES MOINES, Iowa — The nation’s corn and soybean farmers will bring in by far the largest harvest ever this year, the U.S. Department of Agriculture said Thursday in a new report.

Corn farmers are expected to harvest nearly 14.4 billion bushels of corn, up from last year’s 13.9 billion bushel record. The yield of 172 bushels per acre is significantly higher than the previous record set in 2009 of 165 bushels per acre.

Record yields will be set in 18 states, the USDA said, and 10 states including Illinois, Iowa, and Nebraska, the top three producers, have the highest number of ears per corn stalk ever.

A massive harvest has been expected this year as adequate rain and cool temperatures made for favorable growing conditions. The expectations have driven corn and soybean prices significantly lower, but that isn’t expected to make much of a short-time difference in consumer food prices. However, since the grains are staples in livestock feed, lower prices could eventually lead to a decline in the cost of beef, pork, chicken and milk.

The soybean harvest estimate also moved upward to a record of 3.9 billion bushels. The previous record was 3.4 billion bushels in 2009. The per-acre yield is now estimated at record 46.6 bushels per acre, beating the 2009 record of 44 bushels per acre.

After meeting all current demands for corn — including exports and use for animal feed, ethanol and food ingredients — the USDA estimated 2 billion bushels of corn would remain in stock. That’s the highest ending stock in a decade.

The report estimated ending soybean stocks at 475 million bushels, the highest since 2006.

Another positive of the USDA report is that it also predicts record demand for corn and soybeans, said Chad Hart, an agriculture economist with Iowa State University.

That means farmers must keep a close eye on the markets and watch opportunities to sell, he said. Slight movements of pennies per bushel can make a difference in the year’s income.

Despite the strong forecast, concerns have grown in recent days that early cold weather is creeping into the upper Midwest too soon as some crops are maturing later this year because a wet spring delayed planting in northern states.

“It’s a huge concern,” said Ryan Buck, who grows corn and soybeans on about 1,000 acres near Red Wing in southeast Minnesota. “We need all of three weeks yet of warm weather. If we can string together some good weather here the potential is definitely there. The crop looks good, but we just need time.”

A hard freeze, temperatures at 28 degrees or below for at least four hours, causes significant damage to crops.

Most of the concern is focused on Michigan, Minnesota, North Dakota, South Dakota, and Wisconsin.