It is the objective of each bank and association, except for banks for cooperatives, to provide full credit, to the extent of creditworthiness, to the full-time bona fide farmer (one whose primary business and vocation is farming, ranching, or producing or harvesting aquatic products); and conservative credit to less than full-time farmers for agricultural enterprises, and more restricted credit for other credit requirements as needed to ensure a sound credit package or to accommodate a borrower's needs as long as the total credit results in being primarily an agricultural loan. However, the part-time farmer who needs to seek off-farm employment to supplement farm income or who desires to supplement off-farm income by living in a rural area and is carrying on a valid agricultural operation, shall have availability of credit for mortgages, other agricultural purposes, and family needs in the preferred position along with full-time farmers. Loans to farmers shall be on an increasingly conservative basis as the emphasis moves away from the full-time bona fide farmer to the point where agricultural needs only will be financed for the applicant whose business is essentially other than farming. Credit shall not be extended where investment in agricultural assets for speculative appreciation is a primary factor.