US – While recent heavy rains and flooding have caused some corn growers to consider replanting, before doing so, growers should first consider the potential yield at the new planting date and seed and pest control costs, writes Tracy Turner.
In fact, several factors must be considered before growers can make the best decision on whether or not to replant, according to Peter Thomison, an Ohio State University Extension agronomist. OSU Extension is the statewide outreach arm of the university’s College of Food, Agricultural, and Environmental Sciences.
Many growers may be weighing this decision thanks to heavy rains that have caused soil crusting leading to reduced emergence, Thomison said. That has led producers who are seeing poor stands as a result of these problems to consider replanting their fields.
The issue is of concern to growers statewide, particularly in areas with poorly drained soils or in river bottoms, which are more prone to flooding conditions, he said.
“But before growers replant, they need to have strong evidence that the returns from replanting will cover both the replanting costs and net enough of a profit to make replanting worth the time, costs, energy and effort,” Thomison said. “The complicating factor is the quality of the stand.
“Corn may now look pretty mediocre or questionable. But more often than not, the quality of the stand improves as crops warm up and nitrogen becomes available to the stand. That helps to make replanting decisions difficult for growers.”
Thomison said that if growers decide, after completing a crop damage assessment, that they need to replant, they should consider the following:
- Original target plant population/intended plant stand.
- Plant stand after damage.
- Uniformity of plant stand after damage.
- Original planting date.
- Possible replanting date.
- Likely replanting pest control and seed costs.
Other key considerations include herbicide and insecticide programs under late-planting conditions; the cost of replanting, which will vary depending on the need for tillage and chemical application; and the cost and availability of acceptable seed.
“These factors must be weighed against expected replanting yield gains,” Thomison said. “If after considering all the factors there is still doubt as to whether or not a field should be replanted, you will perhaps be correct more often if the field is left as is.
“Sometimes it becomes a trade-off between a poor stand with early planting or a good stand with late planting. Some grower may achieve a higher yield with a late-planted stand.
As of the week ending May 25, 69 percent of corn was planted in Ohio, according to the U.S. Department of Agriculture’s National Agricultural Statistics Service. That compares to 87 percent that had been planted by the same time last year and 74 percent that had been planted on average during the same time period over the past five years, the agency said.
There were 3.2 days suitable for field work in Ohio during the week ending May 25, the federal agriculture agency said.
“In some areas, the low-lying areas are still underwater and may need to be replanted,” it said in a statement. “While producers planted corn and soybeans when the weather allowed, both corn and soybeans planted are behind the five-year average.”
Historically, the optimal time to get corn planted in southern Ohio is between April 10 and May 10 and in northern Ohio between April 15 and May 10. Growers who follow those planting dates generally see optimal yields, Thomison said. Planting later than these times historically has resulted in yield loss -- in some cases, a 30-bushel-per-acre reduction in yield, he said.
Wet weather conditions caused planting delays for many growers in 2011. However, many growers were still able to produce crops with good yields and, in some cases, better yields than average, Thomison said.
Growers can use the chart at agry.purdue.edu/ext/corn/news/articles.08/delayedpltupdate-0523.html to see the effects of planting date and plant population on final grain yield for the central Corn Belt. The chart was developed by Emerson Nafziger at the University of Illinois and modified by Bob Nielsen of Purdue University to provide estimates of potential yield losses for planting dates in early June, Thomison said.