2016 was a year of extremes in our region. Too dry, too wet, too cold! Take your pick! As a result of these conditions, there has been quite a bit of IDC symptoms (iron deficiency chlorosis) in soybeans across the region this year.
This summer, we did a demonstration project to determine which soil properties were different between areas in fields with yellow soybeans (IDC) and adjacent green soybeans in the same field. We did a similar project to this in 2001. We collected soil samples from 41 sites covering eastern ND, NW MN, SW MN and eastern SD. When we summarized the differences in the soil properties between areas with yellow and green soybeans, we found there were differences in carbonates (CCE), salinity (E.C.) or nitrate-nitrogen. Research has shown that as each of these soil properties tests higher, the risk and severity of IDC symptoms increases. Some sites had all three of these factors contributing to the severity of the IDC and others sites had only one or two factors. (See table to right.) There were a few sites where the soil properties were not different between the area with yellow soybeans and green soybeans, which was a little surprising. We did SCN analysis to see if that was a contributing factor to IDC, but did not see a strong relationship.