Deere missed quarterly profit estimates for the fifth-straight quarter and cut its full-year outlook, as the escalating US-China trade war threatens to further hit farm incomes and demand for Deere's equipment.

Shares of Deere, known for its trademark green tractors and harvesting combines, fell 4% to $140 in premarket trading.

US agricultural exports are likely to suffer, as the world's two largest economies level escalating tariffs on each other's imports in the midst of negotiations.

Earlier this week, soybean futures fell to their lowest in more than 10 years, which is squeezing US farmers whose incomes have already been under pressure from a global grain glut. 

China, the world's top importer of soybean, bought about $12 billion worth of US soy in 2017, but mostly shifted purchases to Brazil last year because of the trade fight, leaving US farmers with surplus produce.

"Ongoing concerns about export-market access, near-term demand for commodities such as soybeans, and a delayed planting season in much of North America are causing farmers to become much more cautious about making major purchases," Chief Executive Officer Samuel Allen said in a statement.

Deere, which gets nearly 60% of its sales from the United States and Canada, said it now expects full year equipment sales to rise by 5%, compared with a 7% rise, it had previously expected.

The company lowered its fiscal 2019 profit outlook to $3.3 billion, from its prior forecast of $3.6 billion.

"The lower forecast is partly a result of actions we are taking to prudently manage field inventories, which will cause production levels to be below retail sales in the second half of the year," said Allen.

Some US company executives have warned that costs related to the latest round of tariffs on goods from China will be passed along to consumers in the form of higher prices.

Walmart on Thursday said that prices for US shoppers will rise due to higher tariffs on goods from China.

Net income attributable to Deere fell 6.1% to $1.14 billion, or $3.52 per share, in the second quarter ended April 28, missing analysts' estimates of $3.62 per share, according to IBES data from Refinitiv.

Net sales rose 5.4% to $10.27 billion, and were above the Wall Street's estimate of $10.19 billion.