December 31, 2002
TIME TO CHECK RELATIVE CORN AND SOYBEAN YIELDS
Enactment of the 2002 Farm Bill, along with a recent change in
relative corn and soybean prices, has caused corn to be more profitable
when compared to soybeans. As a result, Illinois farmers may be
considering planting more corn acres and less soybean acres.
A key variable in this decision is relative corn and soybean yields
on a farm. A switch to corn likely will be more profitable when
corn yields are higher relative to soybean yields. In this Illinois
Farm Economics: Facts and Opinions, we examine corn yields relative
to soybean yields. We do this by calculating a corn-to-soybean yield
ratio. This ratio equals the corn yield divided by the soybean yield.
A higher corn-to-soybean yield ratio means that corn yield is higher
relative to soybean yield than for a situation with a lower ratio.
Table 1 shows corn-to-soybean yield ratios for farms enrolled in
Illinois Farm Business Farm Management (FBFM). To be included in
Table 1, a farm had to have yields for every year between 1996 through
2001. For all farms, corn yield averaged 150 bu. per acre between
1996 through 2001, soybean yield average 57 bu. per acre, and the
corn-to-soybean yield ratio was 3.16 (see Table 1).
Corn-to-soybean yield ratios vary across the state, as illustrated
by corn-to-soybean yield ratios by Crop Reporting District. The
West Southwest CRD has the highest ratio (3.27) while the southwest
CRD has the lowest ratio (2.96). This suggests that planting more
corn and less soybean in the west southwest CRD will likely be more
profitable than in the southwest CRD.
A more detailed geographical look at these ratios can be seen in
Figure 1. This figure shows corn-to-soybean yield ratios by county.
In constructing these ratios, county yields obtained through the
National Agricultural Statistics Service were averaged from 1997
Dispersion of high and low county corn-to-soybean ratios is geographically
related (see Figure 1). An area in south-central Illinois has high
corn-to-soybean ratios (Madison, Macoupin, Montgomery, Christian,
Macon, Shelby, and Moultrie counties). Also an area in southern
Illinois near the Mississippi, Ohio, and Wabash rivers has high
Counties with low corn-to-soybean ratios tend to be located in
the northwest part of the state (see Figure 1). A stretch of counties
from Jo Daviess and Stephenson in the north down to Henderson, Warren,
and Knox counties in the south have low corn-to-soybean yield ratios.
Williamson, Saline, and Johnson counties in southern Illinois also
have low ratios.
Areas where corn yields are higher relative to soybean acres are
areas in which more acres are likely to shift to corn. Areas in
the state where this is likely to be most profitable is in south-central
Illinois and some counties in southern Illinois near the Mississippi,
Ohio, and Wabash rivers.
Before deciding to switch to more corn, farmers should examine
their own yield histories. There is considerable variability in
corn-to-soybean ratios from farm to farm.
Issued by: Gary Schnitkey,
Department of Agricultural and Consumer Economics