Texas Sports Turf Managers Association

http://aggieturf.tamu.edu/answers4you/

Additional Details

The above link is the "Answers 4 You" page of the Aggie Turf website.  It is very helpful!

Fertilizer Spreader Calibration Infomation Link:

http://www.rainbowgardens.biz/plants/spreader_calibration_lawns.pdf