The master list of agricultural soil groups for New York State's agricultural land, established and maintained by the department, shall be a list of New York soil map units placed into soil groups, including any subdivisions thereof, based on data developed by the National Cooperative Soil Survey (NCSS) and research data. The master list is established in cooperation with: U.S.D.A. Soil Conservation Service, Cornell University Agricultural Experiment Station and the New York State Cooperative Extension Service using the productivity index system established by section 370.6 of this Part.