Iron plays an important role in soybean development. If there is not enough iron present in the soil, Iron Deficiency Chlorosis (IDC) can develop, affecting soybean coloration and even yields. Fields that are most susceptible to IDC are soils with a high pH (>7.3), poor drainage, compaction, higher soluble salts and/or higher carbonate (lime.)
When scouting your fields, here are symptoms that you should be on the lookout for:
- Interveinal chlorosis – yellowing of the leaf tissue between the veins beginning on the first trifoliate leaves and extending upward to new leaf tissue.
- Plant stunting – affected plants appear stunted compared to unaffected parts of the field.
- General yellowing of the plant – new growth is most affected as iron cannot move within the plant.
- High alkaline and calcareous soils – IDC is most likely to occur on soils with a pH greater than 7.3 that possess high levels of calcium carbonate.
While you cannot fully prevent IDC, there are steps you can take to help manage it in your fields:
- Start with the right variety for your field.
- Your soybean variety is the first line of defense against IDC, so selecting varieties with strong IDC tolerance is a must in fields with high pH or a history of IDC symptoms.
- Within our own soybean lineup, it is recommended to select varieties with an IDC rating of 1, 2 or 3. These varieties provide the necessary tolerance to overcome iron chlorosis related losses.
- Improve soil drainage and reduce soil compaction.
- Making drainage improvements aids in getting rid of excess moisture in high salt areas.
- Soil compaction causes plant stress and slows the release of carbon dioxide from the soil, thus increasing bicarbonate levels and IDC.
- Use an in-furrow iron chelate EDDHA product like Soygreen®1.
- Research has shown these in-furrow applications can be an efficient and cost effective means of getting iron to the soil for plant uptake.
- Test your soils.
- Taking a soil sample will help you begin to properly manage pH levels.
- Test for soluble salts and soybean cyst nematode (SCN). SCN causes plant stress and can mimic IDC symptoms so understanding SCN levels can help identify the real issue.
- Most soil is not low in iron. IDC shows up because available iron is tied up in the soil and plants cannot take up that iron.
- Reduce plant stress.
- Plant stress can cause problems with iron uptake, therefore, reducing that stress helps alleviate iron chlorosis. Examples of plant stress could include compaction, herbicide injury, disease and insect pressure.
- Use a cover crop.
- A cover crop such as oats seeded at 1 bu/A and then killed off with glyphosate at 12” height has been shown to reduce soil nitrate levels.
Contact your Golden Harvest Seed Advisor with questions or for additional agronomic insights.
1Soygreen® is a registered trademark of JAER and is distributed exclusively by West Central Inc.
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