THE PILOT STATED HE WAS TAKING OFF WITH A LOAD OF WATER TO FLUSH OUT HIS AERIAL APPLICATION EQUIPMENT. THE AIRPLANE ROTATED, BUT THE PILOT REPORTED HE WAS UNABLE TO CLIMB OUT OF GROUND EFFECT. THE STALL WARNING HORN SOUNDED AND THE AIRPLANE SETTLED BACK TO THE GROUND, TOUCHING DOWN ABRUPTLY IN A NOSE HIGH ATTITUDE. THE PILOT STATED THERE WAS NO MECHANICAL MALFUNCTION OR LOSS OF POWER INVOLVED. HE STATED, 'I SHOULD HAVE KEPT THE AIRPLANE ON THE GROUND LONGER DURING THE TAKE OFF ROLL.'