Dr. Spiegal is working to compare the outcomes of agricultural production systems, to understand how they promote or detract from the sustainable intensification of US agriculture. Connections among the distant links of the US beef supply chain are a primary focus, from ranching in the Southwest to beef cattle finishing on grains and grass in the Southern Plains and Northern Plains, to marketing strategies in all locations. With an eye toward recycling as a basic component of sustainability, she is also investigating viable strategies for recycling manure nutrients from confined livestock operations in the lands surrounding the operations - to meet environmental, production, and human wellbeing goals of animal and crop producers alike.