A land registry would make it possible to disallow the sale of land by someone with not much land

It would (might) be a good idea to introduce the concept of a minimum piece, quantity of land. This means that the State will not recognise the transfer if someone seeks to sell this land. To sell the land, the landowner would be required to show that they have more land elsewhere.

If the land agencies would refuse to recognise a divestment (selling) of land below the threshold then we can be confident giving to the landless (those without land) a portion of land; they will not be able to sell it for profit. A land registry of land ownership would allow someone to demonstrate their landlessness by challenging the authorities to show which land is owned by them. If no land can be shown it can be assumed that the person is landless. Land can then be given in confidence to this person since we know that they have no land and will not be able to sell the land and claim landlessness once more.

The ability to prove that we have no land enables people to give more confidently and might be a requirement (an obstacle, if we have not much land) to sell land, if we seek to make sure that everyone has a piece of land. A land registry (which enables people to demonstrate that they have no land) would enable people to prove their poverty and make giving land more secure.

If people cannot sell land to the extent that they are landless we can be confident that to give them land will not result in the donation being wasted; they would not be able to sell what has been given to them.