Abstract:
This study investigates county-level corn yield trend models using quadratic and cubic trend
estimations. The study empirically revealed that the cubic trend is more appropriate for yield data from the
West, Midwest and South regions. The linear and the quadratic trend models were respectively found to be
more appropriate for yield data from the Plains and Atlantic regions. Results suggest that the data should be
allowed to determine the appropriate trend relationships to avoid trend misspecification. Additionally, the
yield trends are found to be inconsistent across all the regions. Different locations tend to exhibit different
yield trends. It is therefore recommended that differences between regions be recognized when we conduct
yield trend tests and not to generalize our results to other regions
