Final answer:
Lenders establish their priority lien position based on the doctrine of security interest in the crop lien system.
Step-by-step explanation:
The lenders establish their priority lien position based on the doctrine of security interest. In the crop lien system, farmers used their future crops as collateral for loans to finance their operations. Lenders would then have a priority lien on the crops, meaning they would be the first ones to be paid back if the crops were sold. This ensured that lenders would have a higher chance of recouping their money.