2006 Annual Report: Effect of Crop Rotation on Soybean Cyst Nematode Egg Counts
Use crop rotations to demonstrate the effect of different rotations on reducing soybean cyst nematode egg count levels.
Methods and Materials
Twenty-nine point samples are taken within our plots each year to monitor the impact of crop rotation on cyst nematode egg counts. We plant our plots across these points. Combined with the different demonstrations conducted each year, these points give us different rotations so we can see any trends over time regarding impact of rotations.
The samples are point samples permanently marked in the plots. A composite sample of 10 cores per point sample is taken. Egg counts are conducted at MUís Nematology lab. In 2006, we increased the sampling by adding an additional six plots for a total of 35 plots sampled year to year.
There were 18 point samples which had the rotation of corn following corn, 3 plots of corn followed by soybean rotation and 4 plots of corn followed by winter wheat and over-seeded with sweet clover.
The chart shows only the average number of eggs from the point samples. Research indicates that rotations to corn slowly decrease egg numbers. Also, sweet clover is a host for cyst nematode. Growers planting corn following corn next year may consider fields that have high numbers of soybean cyst nematode. The initial impact will not be dramatic, but with such high numbers as we have at this site, growers need to rotate to a non-host crop then rotate with a resistant soybean variety.