Structural Breaks or Continuous Adjustments in Grain Production and Prices 1961-2014? An Explorative Study
2019
Fretheim, Torun
This article analyses grain production and prices 1961-2014. We first describe the development in aggregated and relative allocation of land worldwide for wheat, corn and soybeans, and the growth in production volumes and yields. We then proceed by analyzing long-term price relationships. Finding that grain prices are strongly co-integrated, we estimate an Error Correction Model to see whether deviations from the long-run equilibrium are quickly adjusted. Furthermore, we investigate whether changes in land allocations for these principal field crops are best described as a continuous process or as a series of structural breaks, hypothesizing that events like the introduction of GM technologies and the “energizing” of corn after 2005 caused structural breaks in acreage shares and relative prices. Given the major and sometimes dramatic political events and technological changes during this period, one would expect to find significant structural breaks in grain production, yields and prices. However, our main conclusion is that grain markets generally adjust smoothly and continuously. Prices adjust quickly towards long-run equilibrium, and the results from a series of Chow tests indicate that the changes in relative land allocations have progressed as a relatively smooth process with few structural breaks.
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