WHAT DO 2003 CORN AND SOYBEAN YIELDS INDICATE ABOUT FUTURE YIELDS?
Yields on many Illinois farms in 2003 can be summarized using six words: excellent corn yields, poor soybean yields. In this article, we compare 2003 corn and soybean yields to historical yields. This examination indicates that it is unusual to have an above average corn yield in the same year as a below average soybean yield. However, this examination does not suggest that the long-term relationship between corn and soybean yields has changed. State of Illinois Yields Figure 1 shows state-average corn yields for Illinois in the years between 1972 and 2003. Actual yields are shown by dots. Also shown by a line are trend-line yields. Trend-line yields increase each year by the average increase in yields between 1972 through 2002. The Illinois corn yield has increased 1.45 bu. per year. The projected yield for 2003 of 169 bu. per acre represents the highest corn yield that has ever occurred in Illinois. The 2003 yield is 21 bu. above the trend-line yield of 148 bu. per acre. The last tim
