The pilot reported that, while conducting an instrument approach at night in instrument meteorological conditions, about 50 ft above the decision altitude of 921 ft, he mistook building lights for runway lights. He inadvertently touched down the airplane in a soybean field about 3/4 mile short of the runway. He then increased engine power to full, and the airplane climbed "a couple hundred feet." Once he established visual contact with the runway lights, he landed the airplane on the runway without further incident. The pilot added that the lateral guidance from the localizer was "dead center" but that he could not recall the position of the vertical guidance needle. The airplane sustained substantial damage to the left wing. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The airport’s automated weather observation station reported that, about 5 minutes after the accident, the wind was from 030° at 3 knots, visibility was 1/2 statute mile with mist, overcast at 200 ft above ground level (agl), temperature 57°F, and dew point 57°F. The pilot reported that the airport ceiling was overcast at 300 ft agl with fog and rain and that visibility was 1 mile.