The National Cotton Council (NCC) expects cotton farming in the world's biggest exporter to fall to 9.4 million acres in 2015. That would be the smallest cotton acreage since 2009, according to U.S. government data.

U.S. cotton farmers are expected to reduce acreage by nearly 15 percent this year as weak market prices force them to switch to other crops.

The NCC survey, widely watched as one of the earliest indicators of the next season's production, is based on a questionnaire mailed in mid-December to producers across the 17-state cotton belt.

The group said that farmers throughout the country would choose to plant other crops, including soybeans, corn, and wheat. The shift comes as cotton prices hover below production costs for farmers in many regions.

According Gary Adams, the group's vice president of economics and policy analysis, history has shown that U.S. farmers respond to relative prices when making planting decisions.

Benchmark cotton futures touched 5-1/2-year lows in January.