By the way, 917 meters equals about 3,000 feet, not 1221 feet...if it is a 3,000 foot runway, a Dehavilland Dash 8 series 100 in cargo configuration would be your best bet, with a payload of about 9,000 lbs , and max take off weight of 34,500 lbs. (An ATR-42 could possibly equal or exceed these numbers, but I am not all that familiar with that type of aircraft.)
If it is the short value of 1221 feet, the best bet would be the Dehavilland DHC-6 Twin Otter. It has a payload capability of about 3,000 lbs weight, and has a max take off weight of 12,500 lbs. It was specifically designed as a STOL (Short Takeoff and Landing) aircraft, and while somewhat expensive to operate in this day and age, carriers in Canada still use them quite extensively in the north, where "bush operations" still take place.
I also thought about the Cessna 208 Caravan, which carries a similar payload, and could possibly take off and land on such a short distance, but I can't say for certain, since I don't know exactly what performance characteristics it has.