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Have your young corn stands reached their tipping point?

Agronomy Bulletin 86 ─ Rootless Corn Syndrome

Situation

Like a house with a poorly prepared foundation, corn plants with rootless corn syndrome (or floppy corn syndrome) between the V3 and V8 growth stage can topple at any moment, leading to stunted growth and even plant death. What causes this phenomenon and how can plants survive?

Factors to Consider

  • Seminal roots
  • Planting
  • Nodal roots
  • Rain
  • Drought conditions
  • Cultivation
Nodal roots unequipped to handle the heavy nutrient demands of young plants cause stalk lodging.

Action Plan

  1. Understand root systems. Corn plants produce two distinct root systems: seminal and nodal roots. Seminal roots anchor and nourish seedlings through coleoptile emergence. Between the V2 and V4 growth stage, the nodal roots take over for the balance of the season, supporting the plant’s developing structure, and providing for water and nutrient uptake. A strong nodal root system reduces the risk of early season lodging and helps plant performance under drought stress conditions.
  2. Study drought damage. Available moisture is critical during the transition from the seminal root support to nodal root support, as well as for subsequent nodal root development. Severe droughts can end the development of nodal roots altogether. In this circumstance, seminal roots will provide a limited amount of nutrients, but not nearly enough to keep up with the growing plant’s demands.
  3. Watch for wilting corn. On hot and dry afternoons, this can be viewed as a potential alert to rootless corn syndrome.
  4. Plant in the right soil conditions and at the right depth. This is the best management mechanism. Planting into fields with wet soil conditions can lead to restricted nodal root growth from sidewall compaction. Also, hot and dry weather following wet planting conditions can fracture soil furrows, leading to a loss of available soil moisture supply. Most universities recommend a seeding depth for corn of 1½ to 2 inches for two reasons. One, this optimizes seed-to-soil contact for proper germination. Two, this depth promotes nodal root system development and maturation to support the growing plant. Ideally, nodal roots begin development between 1 to 1½ inches of soil depth. If planted too shallow, nodal roots are more likely to encounter dry soil challenges.
  5. Welcome the rain. Dry soil conditions can limit the ability of plants with rootless corn syndrome to develop and can severely hamper recovery or even kill plants if conditions are severe enough. But if your plants are leaning over, rainfall can help. Rain that moistens the soil encourages root growth and establishment. Cultivation may help by ridging soil around the base of plants, yet this is extremely difficult in no-till fields and in other fields with leaning plants. Further, moving soil around causes the soil to lose moisture, leading to drier conditions in the upper soil profile in severe drought conditions.

Summary

Yield potential can be at risk during crucial early corn growth stages, which emphasizes the need for a healthy root system. If your corn crop is suffering from rootless corn syndrome, timely and consistent rains can help minimize potential damage and yield loss. For more information, contact your local Mycogen Seeds customer agronomist or trusted agronomic adviser.

Published on Saturday, December 20, 2014