Cool, wet, muddy conditions in May slowed planting and crop growth for soybeans in much of Ohio, while hot, dry soil conditions this month have contributed to uneven soybean emergence, said a field crops expert with Ohio State University's College of Food, Agricultural, and Environmental Sciences.
But unless growers with uneven soybean emergence are able to determine that their seedlings are dead, they may want to hold off on replanting decisions as forecasted rainfall could help more soybeans begin to break through, said Laura Lindsey, a soybean and small grains specialist with the college's outreach arm, Ohio State University Extension.
"When considering replanting soybeans, make sure to take into account the existing stand, yield loss due to late planting, and the cost of additional seed," Lindsey said. "Soybean yield is decreased by approximately half a bushel per acre every day when planting later than mid-May."
Statewide, soybeans are 89 percent planted and 58 percent emerged, according to the June 3 U.S. Department of Agriculture crop progress report. That compares to soybeans at 98 percent planted at the same time last year, with 78 percent emerged during that same period, the USDA said.
Topsoil moisture is 78 percent adequate to surplus in Ohio, with subsoil moisture at 89 percent adequate to surplus statewide, USDA said.
"While soil moisture remains in good condition, there were reports that crops still need more rainfall," the report said. "There were also several reports of a frost in eastern parts of the state that damaged corn, soybeans and vegetables.
"Some corn and soybeans may need to be replanted."
However, Lindsey said, before growers consider replanting due to uneven stand, they should dig around in areas of their fields where there are no plants. Growers who find healthy, germinated seeds that simply haven't broken through the soil yet can wait because the plants could still pop up, she said.
"The soil temperatures have finally reached optimum germination conditions. With a little bit of moisture they will continue to emerge," Lindsey said. "We saw this last year, when soybeans sat in the ground for a full six weeks before they received enough moisture to germinate."
Growers who find dead seedlings, or no seeds or seedlings, should take a stand count to see how many plants are remaining, she said.
One way to estimate stand is to count the number of plants in 35 foot of row for 15-inch row spacing. This represents one-thousandth of an acre, so 120 plants in 35 foot of row grown at 15-inch row spacing represents a stand of 120,000 plants per acre.
"Soybean populations of 50,000 plants per acre yield approximately 15 percent lower than soybean populations of 175,000 plants per acre, according to research by the Ohio State's Agronomics Team," she said. "But they still yield."
Estimates can also be used with 70 foot of row for 7.5-inch row spacing, or 17.5 foot of row for 30-inch row spacing, she said.
Source : purdue.edu