Farmers in the Dakotas’ banana belt – southwest and south central South Dakota -- have already planted a lot of small grains, reports Ruth Beck, South Dakota State University Extension agronomist, Pierre, S.D.
But is it too early to plant small grains elsewhere in the Dakotas?
“I encourage planting small grains early, since they tend to have higher yield potential when vegetative development occurs during the cool days of spring,” says Joel Ransom, North Dakota State University Extension agronomist. “There is a risk of planting too early, however. Small grains tend to be tolerant to cold weather and the growing point remains below the surface of the soil for several weeks after planting and is therefore buffered from freezing air temperatures. Nevertheless, when air temps dip below 22 degrees F for a prolonged period of time, plant stands can be damaged. Therefore, I would encourage growers who are anxious to get started with planting to consider the risk of a serious cold spell (below 22 degrees F) in April and early May.”
When soil temperatures are cold, emergence is also delayed., Ransom says.
“Having a good seed bed with adequate moisture can help in establishing a uniform stand when soil temperatures are still marginal for rapid germination and emergence,” he says.
Here are some facts about spring wheat, barley and oat germination from Jochum Wiersma, University of Minnesota Extension small grain specialist, Crookston,
Small grain seed will start germinating in earnest when soil temperature reach 40 degrees F..
Once the imbibition phase starts there is no return to dormancy and the germination/emergence should be as quick as possible to establish a healthy, vigorous seedling.
Protracted emergence will predispose the seeding to attacks of soilborne fungi like Pythium damping off or common root rot, ultimately reducing stands.
Daytime highs in the 60s and night temperatures around 40 degrees F are best and will allow the crop to emerge in 8 to 10 days and make for a robust stand.
During the germination and seedling emergence, and up to the 5-leaf stage, the growing point will be at about the 1-inch depth. At this depth it is protected from the ambient temperatures. The crown can sustain temperatures down to 28 degrees F and probably even handle short periods of temperatures as low as 22 degrees F. Even if above ground leaves freeze, the plant will survive and continue its development as long as the crown does not suffer any freezing injury.
Wiersma took a look at the risk of winter returning in April and the first half of May in the northern Red River Valley. He studied the weather records from the U of M Northwest Research and Outreach Center in Crookston dating back to 1890.
“If we take the latest 30-year climate normal (1981 through 2010), winter can still return in April and when it does, the number of days the minimum temperatures go below 22 degree F between April 1 and May 15 is relatively small at 9%,” he says. The number of days the nighttime temperatures dips below 28 degree F is much greater at 25%.
“If, however, the warmer weather we have had lately continues and we look at the 30 warmest Aprils on record, these percentages are cut in half,” Wiersma says. Taking the warmest five April months on record, cuts those percentages in half again.
This is somewhat of a roughshod approach, Wiersma notes, as each individual day has its own probability function, meaning that it has its own mean and distribution around that mean. To do these calculations statistically correct you would have to calculate the probability that temperatures dropped below 22, 28 and 32 degrees F for each individual day and then average them out over the same time period. Intuitively you would understand that the risk is greatest in early April and diminishes with each day the season progresses.
“Bottom line: there is a risk of cold weather returning,” Wiersma says. “Frost is likely to return to the region but the odds of really cold temperatures that could damage the crown appear to be relatively small. Of course, if any snow accompanies the cold weather, the snow will act as insulation and reduce the risk of the crowns freezing.”
This year’s tighter profit margins may be worth considering, too.
Scott Johnson, Grand Forks, N.D., isn’t in a rush to start planting.
Margins are so tight this year that the last he wants to do is replant field. He plans to wait a while before seeding small grains.