Corn plants that emerge from the soil within a few hours of each other tend to produce ears of uniform size and weight and that may be more important for good yields than singulation or uniform spacing, according to the results of a recent NDSU Extension project.
The NDSU Corn Emergence and Development project was conducted by Roger Ashley, NDSU area Extension agronomist at Dickinson Research Extension Center, and led by Lindsey Novak, NDSU Stutsman County Extension agent, and Joel Ransom NDSU Extension agronomist.
At Western Dakota Crops Day, hosted by the NDSU’s Hettinger Research Extension Center in Hettinger, Ashley said they wanted to demonstrate the importance of seed placement and its effect on yield.
Results showed if corn plants emerge from the soil at different times, the plants would not produce ears that are the same size at the end of the season.
“Even if some corn plants are one leaf behind the others at emergence, at the end of the year, there could be a reduction in grain produced by the late emerging plant of 25 to 60 percent,” Ashley said. “That translates to lower yields.”
Those corn plants emerging two leaves behind the other corn plants in the row end up with 15 to 60 percent of the grain produced by normally-emerged plants, which translates to significantly lower yields.
While some producers focus on singulation and having corn plant spacing looking like “a picket fence across the field,” Ashley said that may be the wrong thing to focus on.
“From what our southwestern North Dakota spacing project showed, spacing is not as critical as timing of emergence,” he said.
Of course, if there are several feet between corn plants, that is a different story, he added.
“We have to have reasonable spacing.”
According to the project findings, if producers are trying for spacing of 7-10 inches apart, and the producer has a skip within the row where some corn plants are 14 to 15 inches apart, it doesn’t change the yield outcome that much.
But uniform emergence does make a difference in yields.
The DREC project was conducted in a real production setting. Producers in the project fertilized for their own yield goals, planted their own seed, used their normal chemical package, not changing anything about their normal corn production practices.
“We asked producers if we could come in after they seeded and stake out 12 rows of corn plants in three different locations within the field to examine plants as they grew,” Ashley said, adding they were very grateful to the producers who volunteered to allow them to conduct the corn emergence and development project in their fields.
“Without the help of these producers, we would not be able to do research in a real field situation that gives other producers real results,” Ashley said.
The planting rates in the participating fields in southwestern North Dakota were 20,900 plants/acre to 24,000 plants/acre.
As the corn plants emerged, the late emerging plants were tagged, and at the end of the season, Ashley said they hand-harvested to maintain the identity of the ear with the plant that produced the ear.
Distance between plants was measured mid-season to identify “skips” and “doubles.” Individual ears were then hand-shelled, dried and the grain weighed at the end of the season.
Plants that had less than 2 inches between them, called “doubles,” should have had issues with competition. However, the scientists found if those corn plants emerged at the same time, even though they were closer together than the producer planned for, the amount of grain they produced was the same.
The plants that emerged at different times did not have the same amount of grain that the plants that emerged at the same time did.
The project also examined if residue made a difference.
Ashley found that if crop residue was distributed uniformly across the field then uniformity of plant emergence was not affected.
“We need uniform residue distribution and uniform planting depth to have uniform emergence in a no-till planting situation,” Ashley said.
When residue is not distributed evenly across the field, seed does not get placed at the same depth, and temperature variations in the soil can occur, resulting in emergence at different times.
How do producers get even residue across the field?
Most combines have straw choppers that chop the residue and spread the straw out the back, or producers chop it and spread the chaff with a chaff spreader. Chaff and straw running through the combine must be distributed evenly across the entire width of the header.
In no-till situations, using a stripper header is a good way to keep residue evenly distributed and intact.
The stripper header takes only the grain and some chaff into the combine, and keeps most of the straw or residue upright and attached to the ground.
“The stripper header leaves the straw even and there is a better distribution pattern of straw and residue,” Ashley said.
In some situations, draper headers are used to cut close to the ground and then all of that straw needs to be spread back across the width of the cut. But, Ashley noted, stripper headers do a better job of leaving residue in place where it is produced.
“Other guys use a fall strip-till or a spring strip-till to plant their corn crop depending on weather conditions,” Ashley said. “Both work well. If producers don’t want to no-till corn, they can strip-till corn.”
Another way to manage residue is with a row cleaner ahead of the planter openers, he said. Row cleaners clear a band of residue on either side of the disc openers, allowing for uniform soil warming, more consistent depth control and even crop emergence, according to Needham Ag Technologies, Inc.
“Guys with good equipment adjusted correctly can do no-till with row cleaners just fine, even in heavy residue,” Ashley said, adding he has seen it done in states like Illinois and Michigan.
Although the project has just one year of results, Ashley said it does show producers may want to spend more time on the uniformity of emergence rather than on the uniformity of spacing.
Source - http://www.theprairiestar.com/
