The pilot was spreading mineral fertiliser on two irregular shaped properties. The first property was finished on the previous load. The second property had two wires within it and a third adjacent to the eastern boundary. A run was made from south to north passing under the first wire and over the second. At the end a turn was made and a west to east run started, the first in the area. The aircraft passed over the lower wire by 150 feet as a climb was made with the terrain. Crossing the eastern boundary at 50 feet the nose gear leg struck the third wire. Full power was applied and a descent initiated to keep control. Enough control was maintained to allow the aircraft to be put down on a hillside. A heavy touchdown ensued followed by a violent right yaw. During the ground slide the aircraft rolled inverted, losing the right wing, then hit a fence post and finally came to rest the right way up.