Yield estimates could bring big news
The first yield corn and soybean yield estimates based on pod and kernel counts in the field will be coming out on August 10, said University of Illinois crop sciences professor Emerson Nafziger. Producers, buyers, and sellers will be examining these numbers closely.
In years such as this one, with the crops negatively affected by poor weather, people tend to think that the state or national yield estimates are too high. However, Nafziger says that, while the August 1 estimate and final estimate are usually not the same, there is no foolproof way to improve on the National Agricultural Statistics Service (NASS) numbers.
“NASS carefully chooses a sample of fields in which to make counts, and this sample should be representative,” he said. “In a year like this, with many fields having low or even no yield, it is possible for such random samples to miss the average. But it’s not clear that poor fields would be underrepresented.”
This year’s August corn yield estimate would normally be expected to be more accurate than usual due to this year’s early planting and rapid crop development. “Kernel numbers are more or less fixed, and there is at least some idea of how well the crop canopy is holding up, which indicates how well kernels will fill,” Nafziger said. “This makes it possible to get a little clearer idea of yield prospects.”
With the ongoing stress and the inability of the plants to produce enough sugars to both fill kernels and maintain stalks, standability is going to be an issue in the corn fields that will be harvested for grain. Nafziger said that signs point to this being one of the worst years for lodging seen recently.
“Fields under severe stress did not produce enough sugar to produce the lignin that gives stalks their strength,” he explained. “In fields under stress since kernel set, there may be more lignin, but sugars are moving to the kernels, leaving stalks depleted. Loss of leaf area before maturity will contribute to this.”
Even soybean plants may be subject to lodging this year in areas that have had more rainfall or where the crop was irrigated and the high temperatures have encouraged tall plants. Irrigated soybeans at Urbana are more than a foot taller than non-irrigated ones and are already leaning as pod filling gets underway. Modest lodging may not reduce yields if the leaf area remains exposed and the canopy remains full, but plants that move towards horizontal leaning risk compromising some leaf area and with it, yield potential.
The yield picture for the soybean crop is less clear than that of the corn crop. “In traveling through some of the driest areas of the state on August 2, I found better growth than I had expected based on what I saw in the same area in mid-July,” said Nafziger.