The tractor is a copy of a Zetor Chrystal. They were made in different parts of the then Soviet Union. Zetor made the engines and swapped them for transmission from Ursus and Fortschritt bought skid units, I believe. At one time, Ursus were building transmission and 4WD systems for Massey Ferguson.
The chopper was quite a good machine, we had a couple in our area. My neighbour, an agricultural contractor, ran Fortschritt combine harvesters which also proved reliable and lasted well. The factory was in East Germany and was bought by Case IH in 1997.
The choppers were also sold as Mengele.