14 CFR § 137.71

Each holder of a commercial agricultural aircraft operator certificate shall maintain and keep current, at the home base of operations designated in his application, the following records:

The name and address of each person for whom agricultural aircraft services were provided;

The date of the service;

The name and quantity of the material dispensed for each operation conducted; and

The name, address, and certificate number of each pilot used in agricultural aircraft operations and the date that pilot met the knowledge and skill requirements of § 137.19(e).

The records required by this section must be kept at least 12 months and made available for inspection by the Administrator upon request.