The survey counted 14,540 US farms and ranches that were either USDA-certified organic or were exempt from certification because their sales totaled less than $5000.

These operations comprised 4.1 million acres of land, of which 1.6 million acres were harvested cropland and 1.8 million acres were pasture or rangeland.

While there were organic farms or ranches in all 50 states, nearly 20 per cent of the operations were in California.

California also led the nation in organic sales, with $1.15 billion – or 36pc of all US sales.

Nationwide, 2008 organic sales totaled $3.16 billion, including $1.94 billion in crops sales and $1.22 billion in sales of livestock, poultry and their products.

The nation’s certified and exempt organic farms had average sales and production expenses that were higher than those of US farms overall.

Organic operations had an average of $217,675 in sales, compared with $134,807 for all farms as reported in the 2007 Census of Agriculture.

Production expenditures averaged $171,978 per organic farm, compared with the nationwide average of $109,359 for all farms.

* Complete results of the 2008 Organic Production Survey are available here.