Technical Abstract: Forage, grasslands, and grazing lands constitute more than two-thirds of all agricultural land in the U.S. and provide several ecosystem goods and services. Sustaining these ecosystem goods and services sometimes requires the investment of public resources to conserve and protect soil, water, and air resources. Government agencies increasingly are tasked to account for money spent on conservation policies, programs, and practices in terms of environmental outcomes (e.g., how much has water quality or soil quality improved) rather than simple numeric metrics (e.g., km of fence installed, ha of land treated). The Conservation Effects Assessment Project (CEAP) is a multiagency effort to quantify scientifically the environmental outcomes of conservation practices used by private landowners that are supported by U.S. Department of Agriculture (USDA) and other conservation programs. CEAP will inform scientists and practitioners of policy needs and expectations of policy makers to account for the environmental outcomes intended by specific conservation practices. Lastly, CEAP will shed light on gaps in scientific knowledge of conservation outcomes and provide insight as to how to attack researchable problems regarding these practices. The CEAP grazing lands assessment began in 2006. The effort was partitioned into two regions or land resources of rangelands, primarily in the west, and pasture/hayland, primarily in the east. As a first step in the pasture and hayland assessment process, a bibliography of relevant literature was compiled and a synthesis of the scientific literature regarding conservation practices was commissioned and funded by the USDA-Natural Resources Conservation Service (USDA-NRCS) through the USDA-Agricultural Research Service (USDA-ARS) and the American Forage and Grassland Council (AFGC). The current literature synthesis is the result of a two-year effort of pasture, forage, soil, animal, and watershed scientists from across the U.S. who thoroughly searched, compiled, interpreted, and synthesized the scientific literature regarding environmental outcomes from conservation practices on pasture and hayland. In this chapter, we introduce key conservation challenges on pastureland and hayland and describe the process involved in developing this comprehensive literature synthesis.