Adding up potential corn frost damage
If you were late planting corn and your crop's still got some work left to do before it's in the homestretch, a frost this week could be bad news for you.
But, if you're using recent crop data to determine where yours stands, don't be fooled by some common language in reports like USDA's Crop Progress report, says Purdue University Extension field agronomy specialist Bob Nielsen. There's a key addition to each progress category that can lead to some false assumptions.
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"The current USDA-NASS estimates of the kernel development progress of the 2011 Indiana corn crop indicates that 96% of the crop is at the dough stage of development or beyond, 72% of the crop is at the dent stage of development or beyond and only 22% of the crop is physiologically mature," Nielsen says. "Those numbers can be misleading because they represent the percentage of the crop at a given stage OR BEYOND. For example, when 72% of the crop is at the dent stage OR BEYOND and 22% of the crop is mature, then 50% of the crop is actually in the dent stage of development."
Nielsen recommends carrying out "reverse calculations" to get a clearer picture of where your corn stands developmentally. For example, he says it's more accurate to take the amount of the crop shown in USDA's Crop Progress report to be at dent stage (72%) and subtract the amount that's mature. Taking into account such a calculation removes the "or beyond" variability from the equation, leading to a figure of 50% for corn in dent stage, according to this week's Crop Progress numbers, Nielsen says.
That means a potential frost this week could really be painful for a lot of corn fields in his state, Nielsen says.
"Given the estimated percentage of the state's corn crop yet in the dent stage of development or younger, the significance of an early-occurring fall frost or freeze event in the next few weeks should not be underestimated. Keep your fingers crossed!" he says.