Agricultural Retailers Association (ARA):  www.aradc.org/home 

The Fertilizer Institute (TFI):  https://www.tfi.org/

CropLifeAmerica (CLA):  www.croplifeamerica.org

American Seed Trade Association (ASTA):  https://www.betterseed.org/

Fieldwatch:  http://www.fieldwatch.com/

AFREC Research and Info:    mnsoilfertility.com