The Cornucopia Institute has been active for years with the mission of "Promoting economic justice for the family-scale farming community." It is a nonprofit headquarted in Wisconsin. It has issued a number of reports investigating the compromises made as industrial farming comes into the world of certified organic production. In March of 2015, they released two reports on the issue of hydroponic growing being certified as organic.
For the Cornicopia Institute White Paper entitled The Organic Hydroponics Dichotomy- Can a Soil-less Growing System be "Organic", click here.
For an shorter article entitled "Is Hydroponics Organic?" by Linley Dixon, PhD, click here.