A distribution tower of an agricultural distribution machine for spreading granular material comprises a riser pipe supplying a flow of distribution goods to a ring-shaped distributor head for dividing the flow into a multitude of flows of distribution goods along the circumference of the distributor head. At least one of the outflows has a shut-off device. The shut-off device has a track switch by means of which the flow of distribution goods can be guided toward a seed tube or toward a return section. A return device connects to and surrounds the riser pipe. Openings in the riser pipe serve to receive the returned distribution goods. The return section, as well as the seed tube connection, are permanently, pneumatically connected. A method is also provided where it is possible to shut off an optional number of outflows without any resulting major change of the lateral distribution.
