In the agreement between the Secretary and an owner or operator, the owner or operator shall agree—

(1) to place in the program for the period of the agreement eligible wetland areas he designates, which areas may include wetlands covered by a Federal or State government easement which permits agricultural use, together with such adjacent areas as determined desirable by the Secretary;

(2) not to drain, burn, fill, or otherwise destroy the wetland character of such areas, nor to use such areas for agricultural purposes, as determined by the Secretary;

(3) to effectuate the wetland conservation and development plan for his land in accordance with the terms of the agreement, unless any requirement thereof is waived or modified by the Secretary pursuant to section 1306 of this title;

(4) to forfeit all rights to further payments or grants under the agreement and refund to the United States all payments or grants received thereunder upon his violation of the agreement at any stage during the time he has control of the land subject to the agreement if the Secretary determines that such violation is of such a nature as to warrant termination of the agreement, or to make refunds or accept such payment adjustments as the Secretary may deem appropriate if he determines that the violation by the owner or operator does not warrant termination of the agreement;

(5) upon transfer of his right and interest in the lands subject to the agreement during the agreement period, to forfeit all rights to further payments or grants under the agreement and refund to the United States all payments or grants received thereunder during the year of the transfer unless the transferee of any such land agrees with the Secretary to assume all obligations of the agreement;

(6) not to adopt any practice specified by the Secretary in the agreement as a practice which would tend to defeat the purposes of the agreement; and

(7) to such additional provisions as the Secretary determines are desirable and includes in the agreement to effectuate the purposes of the program or to facilitate its administration.