How do I insure a vacant land?

-Agricultural land (undeveloped, may not be developed) 6050m²
-2 owners (not married, not related, both German with residence in Germany)
-Photovoltaic-powered (approx. 1m²) groundwater pump on the property

Unfortunately, there is no landowner liability insurance for this, since the property is located in the Netherlands. Otherwise, it would be insured.

However, there is now the possibility that this is covered by a private liability insurance. There are some that insure properties in Europe (NL) up to this size (often <10,000m²). And also photovoltaic systems.

If now one of the two takes out such a private liability insurance, is that sufficient? So are both property owners then insured against claims for damages by third parties? For example, if someone receives an electric shock from the photovoltaic battery or a branch falls on someone’s head from a fruit tree in the field or a manure heap catches fire and burns down the neighboring house.

Or does the private liability insurance then only pay half the damage because only one of the two property owners was insured?
Or can a third party turn to property owner A (without this private liability insurance) and then he must cover the damage, even if property owner B would have his private liability insurance cover the damage?

Thank you!

So we only took out our building insurance once, even though there are two parties that are the owners. I don't think it will be different for you. But these are questions you have to ask your insurance.