On August 16, 1995, at 0930 central daylight time, a WSK PZL Mielec M-18A, N2065S, was substantially damaged during a forced landing near Wilmot, Arkansas. The commercial pilot was not injured. The aircraft was being operated by Wilmot Aviation Inc., under 14 CFR Part 137 when the accident occurred. Visual meteorological conditions prevailed for the aerial application flight for which no flight plan was filed. According to the Federal Aviation Administration (FAA) inspector, the engine lost power immediately after lift off from a 2,900 foot grass airstrip. The pilot dumped the 500 gallons of chemicals being carried in the hopper prior to impacting the ground. The right wing sustained structural damage upon collision with a water well motor utilized to irrigate the rice paddy. The airplane came to rest on its belly at the edge of a rice paddy at the end of the airstrip. Examination of the engine by the owner's representative did not disclose any anomalies that would have prevented normal engine operation.