A 30-year low in cotton prices has led to a 47 per cent plummet in South African cotton production as farmers switch to more lucrative crops.

Cotton SA, the industry's marketing body, says depressed prices are the result of high agricultural subsidies paid to US farmers which have led to a record harvest of 4 million tons in the US.

In contrast, South Africa's production fell to 82,916 bales this season from 157,515 bales in 2000-01.

A complaint from Brazil about cotton subsidies paid to US farmers is being investigated by The World Trade Organisation. Cotton SA is now lobbying the government to put pressure on the US in the WTO forum.