Science, economics and the design of agricultural conservation programmes in the US.

Conservation programmes in the US have emphasised retirement of land from crop production as a mechanism for achieving multiple environmental benefits. Several features of these programmes, such as their eligibility criteria, participation incentives and length of contract, influence the performance of these programmes and their ease of implementation. The design of these programmes has evolved over time in an effort to increase environmental benefits while lowering costs. This paper reviews the key features of land retirement programmes in the US and their implications for programme effectiveness. In particular, it examines the potential benefits from spatial targeting of programme participants, linking contract length to the ecological services being targeted and relying more on science-based models for improving programme outcomes. Targeted land management focuses conservation practices on those portions of the landscape where they will achieve the greatest gains in environmental quality using limited programme budgets. The scientific basis for targeting conservation efforts is improving through better understanding of ecological and hydrological processes; however, better guidelines need to be developed to incorporate this understanding in developing decision support tools that local programme administrators can use effectively. [ABSTRACT FROM AUTHOR]