Is lending money to farmers, then buying their crops and dealing with them like any other merchant, considered forbidden usury (riba), even though it facilitates things for them and saves them from usurious borrowing?

A loan is a contract of benevolence and graciousness, in which no benefit that accrues to the lender is permissible, such as stipulating that one must buy from him, or appoint him as an agent, or hire him. The predecessors disliked any loan that drew a benefit. If the merchant does not stipulate that the farmers sell their crops to him, then there is no harm in him doing so. However, if there is an explicit or customary stipulation, then it is not permissible.