On July 19, 1993, about 0800 central daylight time, a Bellanca DW-1 airplane, N8815W, sustained substantial damage during a forced landing on a wheat field near Grinnell, Iowa. The solo commercial pilot was not injured. The aerial application flight operated in visual meteorological conditions without plan under 14 CFR Part 137. The flight originated from the Grinnell Airport at 0757. The pilot reported that takeoff seemed normal but the airplane seemed to lose some power shortly thereafter, and was unable to climb more than 100 to 150 feet above the ground despite full throttle. He stated he flew approximately two miles at this altitude and had turned around towards the departure runway when the airplane began settling towards the terrain. He was forced to land in a soft field, and the airplane nosed over during the landing roll.