No trust, other than a family trust, authorized trust, or testamentary trust, shall either directly or indirectly acquire or otherwise obtain or lease any agricultural land in this state, except that the restrictions set forth in this section shall not apply to the following:

(1) A bona fide encumbrance taken for purposes of security;

(2) Agricultural land acquired by a trust for research or experimental purposes, if the commercial sales from such agricultural land are incidental to the research or experimental objectives of the trust, and agricultural land acquired for the purpose of testing, developing, or producing seeds, animals, or plants for sale or resale to farmers or for purposes incidental to such purposes. Commercial sales are incidental to the research or experimental objectives of the trust when they are less than twenty-five percent of the gross sales of the primary product of the research;

(3) Agricultural land which is acquired by a trust company or bank in a fiduciary capacity or as trustee for a family trust, authorized trust, or testamentary trust;

(4) Agricultural land held or leased by a trust on August 30, 1981, as long as the trust holding or leasing such land on such date continues to hold or lease such agricultural land;

(5) Agricultural land acquired by a trust for immediate use in nonfarming purposes; and

(6) Any property held by the State of Nebraska.