This paper studies the spatial price linkages in U.S. grain and transportation markets using cointegration analysis and algorithms of inductive causation on directed acyclic graphs. Transport costs and prices from alternative transportation modes are considered to provide a relatively comprehensive view of the interaction between grain and freight markets over time. Dynamic relationship among corn prices in selected U.S. markets and freight rates, extending from January 1990 to December 2002, are explored. Results suggest the Mississippi Gulf (lower Mississippi River port area) is the most dominant corn market among evaluated export and domestic markets. Also, grain barge rates on the upper Mississippi/Illinois Rivers influence domestic corn markets in contemporaneous time. In the longer-run, significant dynamic relationships among prices in domestic and export corn markets and freight rates are observed; perturbations in transportation rates affect the variation in corn prices considerably. 2007 Canadian Agricultural Economics Society.
