An agricultural row unit includes a towing frame, an attachment frame, and a linkage. A row unit frame has a forward end coupled to the linkage to permit vertical pivoting movement of the row unit frame relative to the attachment frame. A closing-wheel assembly includes a support arm having a leading end coupled to the row unit frame, and a hub assembly mounted at a trailing end of the support arm. The hub assembly has a wheel-fastening mechanism with one or more removable fasteners. The closing-wheel assembly further includes a closing wheel connected to the hub assembly with the one or more removable fasteners such that the closing wheel is interchangeable with different types of modular closing wheels.
