By Barb Baylor Anderson
The hint of an early spring may have farmers itching to get into the field, but crop specialists warn farmers to be patient. The calendar remains a key part of ideal planting strategies.
“We don’t have any snow cover. It is warmer than usual, but it is still March,” says David Kee, Minnesota Soybean director of research. “Optimal planting time for soybeans is still the first two weeks of May. Don’t plant too early, and don’t plant until you have insurance coverage.”
For corn, the University of Minnesota recommends maximum yield comes with planting in late April or early May, although a freeze in May can still damage young corn.
And as long as a late freeze is possible, the risk to seed is still greater than the reward, says Kee. When soil temperatures are below 50 degrees, the crop is not likely to gain a couple of weeks. Over 50 degrees, and chances improve, but Kee suggests farmers still exercise caution.
He says time is better spent now confirming varieties chosen will address problems from 2016. “Plant the right variety from the right maturity group for the right field. Each field is a different entity that requires a unique approach,” he says. “There are no silver bullets, only optimal solutions. With current crop production margins, there is not much wiggle room for mistakes.”
University of Minnesota Extension specialists remind farmers not all soybeans are equal. Soybean seed can have a wide range in yield potential, with the best-yielding varieties producing as much as 20-40 percent more bushels than lower-performance varieties.
Farmers must also determine the best planting population, rate, and depth for each field. In the Upper Midwest, seeding rates will vary by soybean maturity group planted. For example, Group 00s generally perform better at higher populations than Group IIs need.
“Optimize your populations so you can anticipate a uniform harvest with few green soybeans,” says Kee. “Put a pencil to possible seeding rates and choose a rate that works out profitably.”
Generally, seed should be in the band of soil that optimizes soil temperature and moisture, but not so deep that it inhibits seedling emergence. Kee says, on the average that is one to two inches deep with 1.25-1.5 inches being the most commonly recommended soybean seeding depth. He adds when planting late in warm soils, plant to moisture or two inches, whichever comes first. A planting depth of two inches is optimal for corn in most situations in Minnesota, as well.
Research conducted at University of Minnesota Research and Outreach Centers in Lamberton and Waseca finds for corn, “Optimum plant population does not change with planting date or row width, but early-maturing hybrids may require a higher plant population than full-season hybrids. Yield increases resulting from higher plant populations are primarily the result of increased light interception during grain-fill by the crop canopy. The economically optimum plant population will vary according to seed costs and corn prices.”
One economic consideration for soybean farmers is to plant in 15-inch rather than 30-inch rows. University of Minnesota data show soybeans planted in narrow rows out-yield those in 30-inch rows with as much as a five percent yield advantage for every 10 inches of narrowing.
Seed treatments also may protect early-season production potential. Kee says be aware of any potential for seedling diseases and be sure the nutrition package matches soil test deficiencies.
“Make certain your planting equipment is in good working order. Walk your fields. Farmers haave an increasing need to watch their fencelines for drift problems, resistant weeds, and insects,” says Kee. “Finally, manage your optimism like everything else in 2017. Spend your time wisely.”