There is hereby authorized to be appropriated for each fiscal year, beginning with the fiscal year ending , the sum of $500,000,000 to enable the Secretary of Agriculture to further carry out the provisions of , subject to all provisions of law relating to the expenditure of funds appropriated by such section, except that up to 50 per centum of such $500,000,000 may be devoted during any fiscal year to any one agricultural commodity or the products thereof.