Source: farmdoc daily (15):84, Department of Agricultural and Consumer Economics, University of Illinois at Urbana-Champaign.
Summary
While corn and soybean yields have increased over time, corn-to-soybean yield ratios generally have not trended up or down at the national or state levels in the 21st Century. However, there does exist variation in relative yields across states. States in the central Corn Belt region (Illinois, Iowa, Indiana) tend to have higher corn and soybean yields than states in the western Corn Belt and Great Plains (Kansas, North Dakota). In relative terms, as measured by the corn-soybean yield ratio, corn is relatively more productive (higher yield ratios) in the states with lower average corn and soybean yields.
Both corn and soybean yields have trended up over time at the national and state levels. Relative yields, as measured by the corn-to-soybean yield ratios, have not trended up or down at the national or state levels over the last 25 years. Differences in yield levels and relative yields exist across states. States with higher corn yields also tend to have higher soybean yields. States with lower yields tend to have higher corn-to-soybean yield ratios.
U.S. Corn-to-Soybean Yield Ratios
Relative yields of corn and soybeans are often evaluated using a corn-to-soybean yield ratio. We used yields reported by the National Agriculture Statistics Service (NASS) for harvested acres. In 2024, the U.S. yield for corn was 179.3 bushels per acre, while the U.S. yield for soybeans was 50.7 bushels per acre. The 2024 corn-to-soybean yield ratio was 3.54, which equals the 179.3 corn yield divided by the 50.7 soybean yield. This ratio means that one acre yields 3.54 times more bushels of corn than of soybeans.
Since 2000, the U.S. corn-to-soybean ratio has averaged 3.49, with much variation around that average. The highest U.S. ratio of 4.19 occurred in 2003 when soybeans were particularly hard hit by aphids and other pest infestations. The lowest ratio of 3.08 occurred in the 2012 drought year. The extremely dry weather in 2012 had larger adverse impacts on corn, with rain occurring in August helping soybean yields. Statistical tests suggest that the corn-to-soybean ratio has not been trending up or down since 2000. Continue reading Corn-to-Soybean Yield Ratios Across Midwestern States