Researchers at Iowa State University may have discovered a method that reduces the effect of a disease that the Iowa Soybean Association says has caused some farmers to lose as much as half of their crop. Sudden death syndrome or S-D-S is caused by a fungus that lurks in the soil, latches onto the roots of soybean plants and releases a toxin.
I.S.U. plant pathologist Leonor Leander says a university agronomist tried rotating the crops planted on soybean fields and he was able to drastically reduce the effect of S-D-S. Leander says there were pretty impressed, because the plots that had the corn/soy rotation had plants that basically lost all the leaves, but plots just beside those with a three or four- year rotation still showed signs of the disease, but she says the contrast in the plants was “tremendous.”
Agronomist Matt Liebman used a three-year rotation where he planted corn, then soybeans, then oats with a cover crop. Leandro says the effectiveness of the rotation shows the corn may actually be allowing –or even helping — the fungus to survive. She says when you go and put in oats/alfalfa, those are the years where there is no corn or no soybean, those plants may make not as favorable for the fungus to grow.
Both Leandro and Liebman will conduct additional testing to better understand why the crop rotation has been so successful at reducing S-D-S.