The 1985 farm bill directs the USDA to establish an acreage conservation reserve program (CRP). The purpose of this program is to transfer cropland which is highly susceptible to soil erosion to permanent vegetative cover. Reduced soil loss caused by rainfall and wind can help maintain the productivity of the Nation's cropland resources and improve surface water quality in some cases. Removing cropland from active crop production can also help stabilize the incomes of producers and help adjust the production of some surplus commodities. Proposals for such programs as a means for curtailing soil erosion date to the 1930s. Nearly 30 years ago, the Congress authorized a conservation reserve (later known as the Soil Bank). Although implementation was focused on production adjustment and was not closely tied to soil erosion problems, the Soil Bank program removed nearly 30 million acres of the Nation's cropland from production during the late 1950s. Title XII of the 1985 Food Security Act once again makes cropland retirement a feature of U.S. agricultural policy and authorizes a reserve which could range up to 45 million acres in size. The USDA has the option of implementing the CRP in phases by enrolling acreage over the 1986-1990 crop years.