[The Seller Giving the Buyer Another Plot of Land to Benefit From Instead of His [Disputed] Plot]

The answer—and Allah is the granter of success—is that this is permissible, and nothing has appeared to me that would prevent it; for it does not resemble any of the prohibited forms of sale.
Moreover, the scholars of the madhhab have permitted an increase in the sold object after the contract, and what is mentioned in the question is a type of that, or close to it.
The outward sense of the question is that the seller has offered the other land to the buyer willingly, permitting the buyer to benefit from it and cultivate it.
If it is said: An increase in price on account of a debt and deferred payment is prohibited, and this [arrangement] resembles that—even if the increase in one case is in the price and in the other is in the sold object.
We say: The increase here is not stipulated, nor did it enter into the contract; it is from the seller himself, not at the buyer’s request, nor with a prior understanding. Rather, the seller offered it, because an impediment arose to delivering the sold item, in order to compensate the buyer for the benefits of the sold item that he is missing.
If it is said: Why not liken this to a pledge (rahn)?
We say: The aim for which the buyer took the [substitute] land is not the aim intended by a pledge.
Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2