On September 23, 1999, at 1335 mountain daylight time, a Schweizer G-164A, N8731H, impacted terrain following takeoff from Cotton City Airport, a private facility, near Animas, New Mexico. The aircraft sustained substantial damage and the commercial pilot received minor injuries. The flight was an aerial application flight operating under Title 14 CFR Part 137. Visual meteorological conditions prevailed and no flight plan was filed. According to information supplied by witnesses and the pilot, both of whom provided verbal statements to the New Mexico State Police, the aircraft appeared to stall/mush during initial climb following takeoff from the 2640-foot dirt airstrip. In his written statement, the pilot provided information that the aircraft did not have a mechanical failure or malfunction but began to "shudder and settle" immediately following lift off and he attempted to conduct a forced landing to a field. During landing roll, the aircraft nosed over in soft terrain. Based on a reported full fuel load and full chemical load, the computed aircraft weight at the time of the accident was 4,500 pounds, which is the maximum certificated gross weight. No performance data was available. Weather conditions at the time of the accident were visual conditions with variable wind at 6 knots and a computed density altitude of 7,400 feet above mean sea level (msl).