P.L. 91-524 (November 30, 1970) initiated a significant change in commodity support policy. This 3-year farm bill replaced some of the more restrictive and mandatory features of acreage allotments, planting restrictions, and marketing quotas with voluntary annual cropland set-asides and marketing certificate payments to achieve parity prices (the precursor to target prices and deficiency payments). For the first time, the law adopted an annual payment limitation per producer (set at $55,000 per crop). The Act also amended and extended the authority of the Class I differential in federal milk marketing order areas.