There was a time when a lot of land was commonly owned. Not because people back then were all communist; it just made economically and socially sense. I think we're approaching a time, at least in the EU where it would make sense to reinstate this situation. That's why the state should nationalize the land.
The fact that one can own land, is actually quite surprising. You can't own the air, nor the water (not personally, not yet), so why the land? Even if you own land, you usually own it only up till a certain depth. And if the government needs the land, they can take it back, for a fair price, but nevertheless.
When food is scarce and a farm can be run by one family, then it makes sense for society to allow farmers there own land. If they own it, they will do their best to make it as productive as possible and that's good for society. In post industrial society this of course no longer the case. We could produce enough food for our population on a relatively small area used for agriculture. We should in fact important most of our food; it just makes more sense to grow it in countries where the climate is better (plus of course these countries tend to be the poorer countries that could do with the trade).
At the same we have a growing need for recreation and a desire to try to restore our forests, swamps and what have you to something closer to their former glory. The Netherlands are the most densly populated country of Europe, but still only about 30% of the are is used for industry, roads and living. I'd say, let's put the rest in a government run foundation.
The foundation can still lease out land for agriculture, should a need for that arise, but should mostly just put the land to use that gives the population of the country the most pleasure; typically restore forests and wetlands and make them accessible for people to enjoy. Licenses and leases for tourist infrastrure will have to be given out, but that doesn't need to entail ownership of the land.
Private ownership of land was useful for a while, but it is time to get over it and start enjoying what there is. And who knows, maybe even restore the ecosystem a little.