Whenever prior to April 15 in any calendar year the Secretary determines that the total supply of wheat in the marketing year beginning in the next succeeding calendar year will, in the absence of a marketing quota program, likely be excessive, the Secretary shall proclaim that a national marketing quota for wheat shall be in effect for such marketing year and for either the following marketing year or the following two marketing years, if the Secretary determines and declares in such proclamation that a two- or three-year marketing quota program is necessary to effectuate the policy of the chapter.