Will frosted corn recover
U of I's Emerson Nafziger says dry soils and cold temps didn't help the freeze situation last week.
Published: Apr 18, 2012
Temperatures fell into the upper 20s on one or more days during the week of April 16 over most of central and northern Illinois. Officially, the low temperatures at Urbana were 29 on April 11 and 31 on April 12, but temperatures lower than this were reported by other observers.
According to official records, 1 percent of the Illinois corn crop was planted by March 25 and 5 percent by April 1. The corn that we planted at Urbana on March 16 was approaching the V3 stage by April 11, and the corn planted on March 29 was up and approaching the V1 stage. Based on this, we can safely conclude that nearly all of the corn planted before April 1 was emerged when frost occurred, and the earliest-planted corn was 5 to 6 inches tall with 3 leaves fully emerged.
By Friday April 13, severe damage was visible on the early-planted corn, with most or all of the above-ground leaf area dead. As we have seen before following frost on corn plants this size, plants with severe leaf loss often were randomly spread down the row, singly or in groups of two or three plants, alternating with plants that appeared to have little injury.
Plants near the grass border were all damaged, and out into the field, 20 to 30 percent of the plants were damaged.
This situation is similar to what we saw in 2005, when temperatures reached the upper 20s during the first few days of May. Corn planted in early April in 2005 was in the V2-V3 stage, and just as we saw this year, plants were randomly damaged or killed down the row. In that event, about a third of the plants died, and the rest regrew slowly as it stayed cool and dry for some time after the frost.
It’s risky to draw parallels between that event and this one, but if this crop responds like that one did, the damaged plants may fail to recover fully, and yields may suffer even if plants stay alive. In 2005, the frost-damaged crop was part of a planting date study with different plant populations. In that dry year, 25,000 plants per acre produced more grain than did higher populations. Thinning to 25,000 plants removed some of the damaged plants, but even so, the yield from the March 31 planting was only 58 bushels per acre, compared to 130 bushels from the April 19 planting and 140 bushels from the May 9 planting. In other words, plants that survived the frost yielded less than half as much as undamaged plants from later plantings.
While we hope that the recovery of the crop in 2012 is better than that of the 2005 crop, there’s no way to predict that. We do have the advantage that it’s still early enough to allow us to watch the crop for another week or so before we need to make the decision to replant. The first task as we wait is to count the remaining plants. If by April 20 or so there is little green leaf area on a plant, it’s probably best not to count that plant.
The article and related photos were provided by U of I 's Emerson Nafziger.
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