One fine spring day, you drive by your soybean fields and they look green and beautiful and you think to yourself, "Man, I am good at growing beans!" The next week, you drive by and see a nasty yellow color starting to cast a pall over your beautiful beans and you say to yourself, “What’s going on?" Such is the story virtually every spring for growers in the Red River growing areas of the North. The culprit: iron deficiency chlorosis (IDC), caused by a deficiency in iron (Fe) (Figure 1). If Fe deficiency is severe, plants can die because of the loss of photosynthetic energy after leaf and growing point death.
Primary factors to help manage IDC include:
Soybean Product Selection: The most important practice is selecting soybean products with tolerance to IDC. Product selection is particularly important for fields with a history of IDC or soils with high levels of salts and calcium carbonate. Your Channel Seedsman or agronomist can assist you in understanding the IDC ratings of the soybean products available for your area and determining the appropriate product(s) for your fields. North Dakota State University conducts field trials that compare IDC ratings among products each year, so look for their publication as well.1
Fe Chelate Products: Consider using a seed placement method of an Fe chelate product that is in the ortho-ortho form. University research has found yield benefits of ortho-ortho chelated Fe applied at planting in the seed furrow. Maximum return on investment has been found to occur when these products are used in areas moderately to severely affected by IDC.2 Always consult the product label for rates and application information.
Additional Considerations: Other management considerations include minimizing nitrate carryover from year to year, targeting fields testing low in residual nitrate and planting a companion crop such as oats. The companion crop may absorb excess nitrate nitrogen and soil moisture to reduce bicarbonate buildup, possibly keeping soil Fe available for the soybean crop.2 Research has also found that a higher seeding rate may result in less severe chlorosis and higher yield potential when targeted to the most IDC-prone areas of a field. Looking at field yield history and satellite imagery with a tool like the Climate FieldView™ platform will help you to focus on those problem areas as you strive to incorporate solutions to keep your soybeans green all spring.
1Kandel, H. and Goos, J. 2011. Iron deficiency chlorosis in soybean. Crop & Pest Report. North Dakota State University.
2Kaiser, D.E., Lamb, J.A., and Bloom, P.R. 2011. Managing iron deficiency chlorosis in soybean. University of Minnesota Extension. http://www.extension.umn.edu/