To be eligible for registration as a professional soil classifier or certification as a soil classifier-in-training, an applicant must be of good character and reputation and shall submit a written application to the board containing such information as the board may require, together with three references, one of which must be from a professional soil classifier having personal knowledge of the applicant’s soil classifying experience; or in the case of an application for certification as a soil classifier-in-training, by three character references.