Replant or Not? Consider these factors first.
Agronomy Bulletin 79 ─ Central Corn Belt Replanting
If your central Corn Belt fields have been damaged by heavy rain, hail, pests or poor emergence, you may consider replanting.
Factors to Consider
- Yield potential of existing stand
- replanting costs
- Yield potential of replanted corn
- Late-season crops
- Replanting date
- Crop insurance adjustments
- Calculate yield loss from less-than-optimum plant population. To estimate yield loss due to stand reduction, first determine the plant population of the existing stand. Then refer to Table 1 to determine the potential yield loss based on existing plant population. For example, in Table 1, assuming an optimum plant population of 30,000, a grower can expect a yield loss of 12 percent when plants per acre drop to 18,000.
- Factor in additional yield loss for nonuniform stands. Uniformly spaced plants produce more yield than unevenly spaced plants. Large gaps of 2 feet or more in the stand can reduce grain yield by about 5 percent in populations of 14,000 to 28,000 plants per acre. If plants are uneven, add another 5 percent to the estimated yield loss due to stand reduction.
- Estimate yield loss due to later replanting date. Using Table 2, determine the expected yield loss for a later-than-optimum planting date. For example, with a replant date of May 30, a grower could expect a yield reduction of 13 percent. Note that optimum planting dates vary by location.
- Compare yield potential to determine if replanting is worthwhile. Using the examples cited, a grower could expect a yield loss of 12 percent due to stand reduction and a loss of 13 percent due to delayed replanting. Therefore, the yield potential of the replanted corn does not outweigh the yield potential of the existing stand and the grower would probably choose not to replant.
- Other considerations. If corn is severely damaged, another option to consider is switching to a later-season crop. If you do choose to replant, a local crop consultant or agronomist can help select hybrids with shorter relative maturities appropriate for your area. Be sure to look into crop insurance adjustments when replanting or switching to a later-season crop.
When faced with a replant situation, analyze all factors to determine whether the yield potential of the replanted corn will offset the cost of replanting. For more information about replanting, contact your local Mycogen Seeds commercial agronomist or trusted agronomic adviser.