Nationally, both science and agricultural education professional organizations have identified agriculture as a fundamental technology to be studied by students, with the goal of achieving an understanding of the agri-food system necessary for democratic participation. Benchmarks representing the content that K-12 children need to understand about the scientific and technological underpinnings of the agri-food system have been developed by agricultural and science educators. However, the benchmarks were developed without empirically based evidence on what existing agri-food system knowledge students held. This study examines students' understandings about science and technology concepts underpinning benchmarks for agricultural literacy. Urban upper elementary student concepts of the origins of food, the selection of plants and animals used for production, how people living in harsh environments obtain crops, and the prevention of food spoilage were probed. Using Piaget's theory of schema development, students' understanding of agricultural technology were compared to grade-specific benchmarks for agricultural literacy and examined for relationship to students' backgrounds and experiences. In comparison to the benchmark goals for the age group, informants' schema for the role that science and technology plays in the agri-food industry was nearly nonexistent. This study suggests that existing agricultural literacy benchmarks, as designed, may not be age and/or developmentally appropriate. Additional suggestions indicate that underlying sub-concepts needed for learner understanding may only be loosely connected to any meaningful experience of urban elementary students. (Contains 6 tables.)