N.M. Stat. § 19-7-39
Such assignments shall be executed on forms to be prescribed by the commissioner of public lands, which forms shall specify the number of the lease or purchase contract assigned, the description of the land embraced in such lease or purchase contract, the date of the expiration of the lease assigned, the name of the assignee and the amount of the indebtedness which the assignment is given to secure, and may provide for further advances by the assignee up to a specific amount. Such assignments shall be acknowledged by the assignor in the manner provided by law for the acknowledgment of conveyances affecting real estate, and, when filed in the office of the commissioner of public lands and approved by him, shall be constructive notice to all persons of the contents of such assignments from the date of such approval, and it shall not be necessary to record such instruments in the county where the lands affected thereby are located. Provided, that when more than one lease or purchase contract is assigned to secure the same indebtedness, any and all such leases or purchase contracts shall be assigned by separate instrument.
NMS § 19-7-39