A regional analysis of corn yield models: comparing quadratic versus cubic trends

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