For a period of three years from May 28, 1956, no agricultural commodity determined by the Secretary of Agriculture in accordance with subsection (c) to be in surplus supply shall receive any crop loans or Federal farm payments or benefits if grown on any newly irrigated or drained lands within any Federal irrigation or drainage project hereafter authorized unless such lands were used for the production of such commodity prior to May 28, 1956.

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.

On or before October 1 of each year, the Secretary of Agriculture shall determine and proclaim the agricultural commodities the supplies of which are in excess of estimated requirements for domestic consumption and export plus adequate reserves for emergencies. The commodities so proclaimed shall be considered to be in surplus supply for the purposes of this section during the succeeding crop year.

For the purposes of this section the term “Federal irrigation or drainage project” means any irrigation or drainage project subject to the Federal reclamation laws (Act of June 17, 1902, 32 Stat. 388, and Acts amendatory thereof or supplementary thereto) in effect at the date of the adoption of this amendment and any irrigation or drainage project subject to the laws relating to irrigation and drainage administered by the Department of Agriculture or the Secretary of Agriculture.