Minecraft wiki entry for Melon, associated text: A melon drops 3–7 melon slices when broken by hand, using tools, or by the movement of a piston. Silk Touch causes the block itself to drop. Fortune increases the maximum number of melon slices dropped. The actual amount is capped at 9, so Fortune III simply increases the chance of getting 9 slices, which is sufficient to craft the melon again from the slices.