On March 24, 2003, approximately 0830 mountain standard time, a Beech A36, N435P, registered to and operated by San Juan Pilot Training, Inc., doing business as Mesa Pilot Development, was substantially damaged when it departed the runway during takeoff and struck a runway light and sign at Farmington, New Mexico. The student pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the instructional flight being conducted under Title 14 CFR Part 91. The local flight originated at Farmington approximately 0820 mountain standard time. The following is based on a telephone interview with, and the accident report submitted by, the pilot. The pilot made a full-stop soft field landing on runway 07. As he taxied back, he decided to practice a soft field takeoff. After lowering the flaps to 12 degrees, he applied full power and lifted off. He applied slight right rudder to maintain the proper track and lowered the nose to see the runway and to "get into ground effect." The airplane began drifting to the left and he applied more right rudder. The airplane "appeared to lose lift." As the pilot tried to return the airplane to the runway centerline, he "felt a hit on the bottom of the plane" as it touched down in the dirt. The pilot said he was able to bring the airplane to a halt. He said it "steered OK," so he taxied it back to the ramp, but "felt obvious damage somewhere to the plane." Examination disclosed holes in the horizontal stabilizer and left elevator and a cracked trim tab. The aft spar of the horizontal stabilizer was also bent.The left landing gear door and left flap were destroyed and a wing rib was bent. The bottom of the fuselage, aft of the wing flap, was dented and the bulkhead was buckled. Winds before and after the accident were from 090 and 100 degrees at 6 and 5 knots, respectively.