The objective of this study was to reach a judgment of the amount of U.S. cropland likely to be in some form of conservation tillage in 2010. The future spread of conservation tillage will be conditioned primarily by farmers' perceptions of its economic advantages relative to conventional tillage and by society's perceptions of its advantages and disadvantages with respect to the environment. Accordingly, the study first considers the economics of conservation tillage relative to conventional tillage, examining differences between the two technologies in the quantities of resources used and in yields. The conclusion is that conservation tillage typically uses less of certain resources and more of others, but that on balance it requires 5 to 10 percent less expenditure per acre than conventional tillage. Yield differences vary widely, depending fundamentally on soil characteristics and climate, but on well-drained soils in the Corn Belt, Southeast, and much of the Northern and Southern Plains where weeds can be controlled by herbicides, yields with conservation tillage are fully competitive with yields of conventional tillage. The conclusion is that the economic advantages of conservation tillage could induce farmers to adopt it on 50 to 60 percent of the Nation's cropland by 2010. A little less than 25 percent of cropland was in conservation tillage in 1979.