Is it permissible to mortgage agricultural land to a person in exchange for a sum of money, with him benefiting from it without rent, on condition that the land be returned upon repayment of the amount?

Pledging land as security for a debt is permissible, but it is forbidden for the creditor to benefit from the pledged land in return for the debt. This falls under the principle: "Every loan that draws a benefit is usury (riba)," unless the pledger grants permission for that to the pledgee without any compensation.