The accident happened on the eastbound A90 Perth to Dundee road, near to Tofthills Farm in Perthshire at around 3.15pm.
Following the collision the van left the road and rolled down an embankment.
Three men have been injured in the incident, although none of their injuries are understood to be life-threatening.
The driver of the van was trapped in his vehicle with serious leg injuries. His passenger is reported to have sustained head and pelvis injuries.
The driver of the farm vehicle was complaining of a back injury. He and the van’s passenger were taken by ambulance to Ninewells Hospital in Dundee, while the emergency services worked to free the van driver.
Police closed the eastbound carriageway at Friarton Bridge and at Kinfauns. The westbound carriageway remained open.
Anyone who witnessed the collision is asked to contact Tayside Police on 0300 111 2222.