The study develops a conceptual framework for analyzing the allocation of conservation funds via selectively offering incentive payments to farmers for enrolling in one of two mutually exclusive agricultural conservation programs: retiring land from production or changing farming practices on land that remains in production. We investigate how the existence of a pre-fixed budget allocation between the programs affects the amounts of environmental benefits obtainable under alternative policy implementation schemes. The framework is applied to a major agricultural production region using field-scale data in conjunction with empirical models of land retirement and conservation tillage adoption, and a biophysical process simulation model for the environmental benefits of carbon sequestration and reduction in soil erosion.