If we use Insurance prices for proxy for prices in general, what do we find, in terms of yield.

Relationship between Percent Change in U.S. Yield and Revenue

The relationship between percent change in U.S. yield per planted acre and U.S. revenue per planted acre over the crop insurance coverage period varies notably across the 6 crops analyzed. The correlation between these two variables ranges from +0.55 for sorghum to +0.01 for soybeans and 0.00 for corn (see Figure 1). Statistical confidence that the correlation differs from 0 is 99% for sorghum and upland cotton, 91% for wheat, 74% for rice, 4% for soybeans, and 1% for corn. Thus, at the conventional 90% confidence test level, only 3 crops (sorghum, cotton, and wheat) have a statistically significant relationship between percent change in yield and revenue per acre over the crop insurance coverage period.

To illustrate the difference in correlation values, a scatter chart of the percent change in revenue observed for a given percent change in yield of sorghum, soybeans, and corn are presented in Figures 2, 3, and 4. The figures also contain the linear line associated with the correlation value. Only the line for sorghum visually differs from a horizontal line. A horizontal line is associated with a correlation of 0.00.