THE AERIAL APPLICATION FLIGHT HAD DEPARTED FROM A REPORTED SOFT SURFACED SOD RUNWAY. ACCORDING TO THE PILOT THE AIRPLANE SETTLED INTO MATURE CORN SHORTLY AFTER THE 'NORMAL TAKEOFF.' AN EYEWITNESS CONFIRMED THE PILOT'S STATEMENT AND ADDED THAT THE AIRPLANE DID NOT APPEAR AS THOUGH IT WAS GOING TO TAKEOFF. AN ON-SCENE INVESTIGATION REVEALED THAT THE RUNWAY SURFACE WAS SOFT AND THAT NO PRE-CRASH AIRFRAME OR POWERPLANT MALFUNCTIONS COULD BE IDENTIFIED.