I'll agree that wind turbines' effect on arable land is much, much lower than solar. That being said, there is still some effect. After all, the land is rendered useless during installation and certain types of maintenance (maybe these cycles could be scheduled when the land lies fallow), and there has to be certain infrastructure (roads/paths) for maintenance.
I'm not against using wind where it is particularly efficient (old strip or surface mining areas may be particularly great); I just think it needs to make economic as well as ecological sense. Wasting a bunch of industrial capacity (largely powered by fossil fuels still) to create wind and solar energy that are more expensive and less efficient at scale than, say, nuclear seems like a bad idea.
There are large areas affected by open pit lignite mining, and presumably candidates for solar in Germany.
This source says there are 179,490 hectares or 1,795 sq. kilometers or 693 sq. miles of former mines.[1]
[1] https://www.cleanenergywire.org/factsheets/coal-germany