A seeding machine (10) is disclosed- The seeding machine (10) is configured to move seed along a seed path defined by a seed-transport belt (82). The seeding machine comprises a seed-transport belt (82) and a belt tensioner assembly. The seed-transport belt (82) being contained, at least in part, by a belt housing (70) and being supported by a fixed belt support that is fixed with respect to the belt housing (70). The belt tensioner assembly comprising: an adjustment mechanism having an input member accessible from outside the belt housing (70) and having a positioning member disposed within the belt housing (70), the positioning member changing positions in response to user input applied to the input member； a transfer mechanism having a first end coupled to the positioning member and moving in response to the change in positions of the positioning member； and a movable belt support supporting the seed-transport belt (82), the movable belt support being coupled to a second end of the transfer mechanism and movable with respect to the belt housing (70)； wherein user input to the adjustment mechanism changes the position of the positioning member to move the transfer mechanism and drive the movable belt support one of toward or away from the fixed belt support to vary the tension of the seed-transport belt (82).
