Farmers definitely don’t want to replant a corn field unless absolutely necessary to assure an economical crop to harvest, and, therefore, retailer agronomists and crop consultants are often expected to help farmers make the nay or yea decision.
Pioneer Hi-Bred provided some basic guidelines with the very first decision being completely based on the cost of replanting. “When corn stand loss occurs, replanting should be considered if the resulting yield increase will more than cover the cost,” the seed company notes.
The yield increase must be sufficient to pay for all of the costs associated with replanting such as extra herbicide or tillage costs, planting costs and increased grain drying costs.
- Plant density of the current stand
- Uniformity and health of the current stand
- Date of original planting and potential replanting
- Costs associated with replanting
- Crop insurance provisions
- In situations such as flooding damage, only a portion of the field may need to be considered for replant
- Frost or hail can damage a wide area. In this case plant density and health should be assessed across the entire field
- Probability of an autumn freeze prior to physiological maturity of replanted corn
- Increased susceptibility of late-planted corn to summer drought or disease and insect pests such as gray leaf spot and European corn borer
Additionally replant yield potential has to be considered. “The expected yield from the current stand should be compared to expected replant yield,” Pioneer stresses. The table shows yield potential for a range of planting dates and final plant populations for the major portion of the Corn Belt.
The maturity of the hybrid being used in replanting is also extremely key. Pioneer says 17 years of research in 29 north-central Corn Belt environments shows the best results using a mid-maturity hybrid if replanting after May 17 and an early maturity hybrid if replanting after June 5.
Additionally Pioneer suggests “replanting to soybeans may be preferable after mid-June, but this will depend on soil-applied corn herbicides that were used.”