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Build a soybean defense strategy against IDC.

Agronomy Bulletin 74 ─ Iron Deficiency Chlorosis

Situation

Iron deficiency chlorosis (IDC) of soybeans is a physiological disease caused by iron deficiency capable of sizable reductions in yield potential. Know and understand how to mitigate your risks.

Factors to Consider

  • Favorable conditions
  • Variety selection
  • Nitrate carryover
  • Applying iron chelates
Soybean varieties differ in IDC tolerance.

Action Plan

  1. Understand conditions that lead to IDC. Iron is an essential nutrient for soybean plants. It is required for energy and chlorophyll development; hence, the yellow leaves of an IDC-infected plant. Though the nutrient is usually abundant in soil, soybeans take in iron inefficiently, particularly in high-pH soils. However, pH levels do not directly correlate to IDC. Instead, test for high concentrations of calcium carbonate and soluble salts, which both intensify IDC, particularly in wetter and cooler seasons.
  2. Minimize nitrate carryover. Limit nitrogen fertilizer applications to the crop preceding soybeans in the rotation. Excess soil nitrates can worsen IDC by further inhibiting iron intake.
  3. Select tolerant seed varieties. Most important, select soybean varieties with tolerance to IDC. Over time, soybean varieties have improved, with many becoming increasingly tolerant of IDC-generating conditions. Click on a product to review its rating.
  4. Consider fertilizer with EDDHA Iron chelates at planting. This infuses iron into the seed. While the EDDHA formula is more expensive, it’s the most effective in keeping iron available in the plant long enough to prevent IDC from developing. Foliar application of iron chelate may work, although forecasting timelines and quantities is difficult, as research is ongoing. Simply adding iron fertilizer to soil will not correct IDC.

Summary

Avoiding IDC in soybeans begins with preparation. If your crop is especially vulnerable, select IDC-tolerant varieties and apply iron chelate fertilizer at planting. Your local Mycogen Seeds customer agronomist or trusted agronomic adviser can help assess your risk level and defense options.

Resources

Published on Monday, August 05, 2013