Some pictures may be worth 1,000 words, as the old saying goes, but the one presented here needs some explanation. At first glance, this seems like an overwhelming conclusion. A plant spike emerging within a window nine to 14 days or more after the first plants emerge is a failure, with only a few kernels. But the next ear of a plant that also emerged very late weighed about 0.2 pounds.
“You have to know the background to understand what could have happened,” says Dave Nanda, director of genetics for Seed Genetics Direct, sponsor of Corn Watch ’21.
Related: Can You Pick The Heavier Ear?
The field was sown on April 25. Then three weeks of very cool weather – well below normal temperatures, with some freezing temperatures in the morning – lasted for the next three weeks. The first plants began to emerge about 11 days after planting, but emergence continued over the next two weeks.
“The goal is rapid and uniform emergence, but that’s not always what happens in the real world,” says Nanda. “There is a microenvironment around every plant, which includes things like seed spacing, seed depth, soil moisture level, etc. Several factors were at play in this area.
Here’s what this emergence plot project revealed:
Uniform emergence pays off. The average weight of the ears in 1/1000 acre in this row where emergence of plants was reported and cobs were harvested by hand was about 0.3 pounds including the cob. Plants that emerged on the first day weighed an average of 0.39 pounds, with one day, two to three days, seven to eight days, and nine to over 14 days late averaging 0.28, 0.33, 0 , 28 and 0.2 pounds per ear, respectively. In this row, 10 of the 32 plants, or nearly a third, emerged nine to 14 days after the first plants. Two of the 10 did not produce an ear.
Obviously, the tendency was for larger spikes if the plants emerged in time.
Early emergence does not guarantee success. Early emergence on day one increased the chances of better performance, but it did not guarantee it. An ear from a plant that emerged on the first day produced a lower than average weight for the row. Two plants emerging in the last window weighed above average.
“We are seeing trends towards better performance with early emergence, but it’s not quite cut off,” says Nanda. “Maize is a complex crop, and many factors affect the performance of a plant.”
The loss of nitrogen harms all plants. This row was in the area of the field most affected by nitrogen loss due to wet soils in May and early June. The land was not tiled. The yield level was about 130 bushels per acre in this row, while it was 215 bushels per acre in other rows that were marked and weighed.
“We don’t know how the early nitrogen deficiency that we observed here may have interacted with late emergence,” says Nanda. “We cannot separate one from the other.