Includes bibliographical references (p. [77]-83) and index.

Introduction -- Results in brief -- Background -- Available data show conversion of native grassland to cropland continues, and these conversions add to farm program costs -- Farm program payments, rising crop prices, and the adoption of new farming technologies provide incentives to expand crop production on native grasslands -- Sodbuster has had little impact on native grassland conversions -- Conclusions -- Appendix I: Objectives, scope, and methodology -- Appendix II: National resources inventory data on net changes in U.S. land use, 1982-2003 -- Appendix III: Census of agriculture data on net changes in uses of land in farms for the United States and selected states -- Appendix IV: Partial budget analysis for a proposed conversion of native grassland to cropland in central South Dakota, 2003-2007 -- Appendix V: Summaries of economic studies examining the impact of farm program payments.