“Payment for ecosystem services” (PES) is a market-based approach to protecting and restoring the environment. The growing attention to PES from scholars, practitioners, and the conservation community is not just for its potential to enhance the services nature provides for society, but also for its potential to enhance the economic prosperity of the suppliers of those services, including agricultural landowners. However, a number of challenges persist on the demand side of the equation. In particular, who will pay landowners for their stewardship?