From the most recent Corn & Soybean Classic, Dr. Emerson Nafziger presented the following data.
Table 1 Corn Grain Yields in Various Rotations in Northern Illinois____
Year___________ Ave % of
2008 2009 2010 2011 Yield SC
Rotation —————————–Bu/A———————-
Continuous Corn* 202 184 159 170 180 87
Corn-Soybean 220 214 197 186 205 100
1st Yr Corn in C-C-SB 216 211 191 186 202 98
2nd Yr Corn in C-C-SB 211 196 177 175 191 93______
*4th Yr Continuous Corn Plus
At our Agronology 10 Research Center at Walcott, we are measuring an 11% yield difference on corn following soybeans vs. a long term continuous corn rotation. Another item to note from the Illinois work is that soybean yields have increased 5% in C-C-SB vs. C-SB rotation.

Table 1 Corn Grain Yields in Various Rotations in Northern Illinois____
Year___________ Ave % of
2008 2009 2010 2011 Yield SC
Rotation —————————–Bu/A———————-
Continuous Corn* 202 184 159 170 180 87
Corn-Soybean 220 214 197 186 205 100
1st Yr Corn in C-C-SB 216 211 191 186 202 98
2nd Yr Corn in C-C-SB 211 196 177 175 191 93______
*4th Yr Continuous Corn Plus
At our Agronology 10 Research Center at Walcott, we are measuring an 11% yield difference on corn following soybeans vs. a long term continuous corn rotation. Another item to note from the Illinois work is that soybean yields have increased 5% in C-C-SB vs. C-SB rotation.
