The Secretary of the Interior and the Secretary of Agriculture shall cause to be included, in all irrigation, drainage, or flood-control contracts entered into with respect to Federal irrigation, drainage, or flood-control projects hereafter authorized, such provisions as they may deem necessary to provide for the enforcement of the provisions of this section. For a period of three years from May 28, 1956, surplus crops grown on lands reclaimed by flood-control projects hereafter authorized and the lands so reclaimed shall be ineligible for any benefits under the soil-bank provisions of this Act and under price support legislation.