WASECA, Minn. – Minnesota crops are moving into the final stretch of the season – a little later than normal. The wheat and oat harvests have had a slow start, corn and soybeans are just getting into the final reproductive stages, and potato harvest is just beginning.
“Both corn and soybeans are a little behind what I'd expect, partly due to we certainly had a troubled planting season,” said Tom Hoverstad, scientist with the University of Minnesota Southern Research and Outreach Center, on Aug. 19. “We're just a little bit short on growing degree units, but I don't think those fields are in any kind of trouble.”
According the Southwest Research and Outreach Center, as of Aug. 19, there had been 1,840 growing degree days since May 1. Historically, there are 1,927 GDDs by this time.
“We're about 4 percent short on growing degree units, which in the grand scheme of things isn't a lot,” said Hoverstad. “Even the later planted crops are probably only about 10 percent short on heat units, but an early frost would not be what we're looking for.”
USDA’s most recent Crop Progress and Conditions Report for Minnesota, for the week ending Aug. 16, the corn crop is rated at 55 percent good-to-excellent and the bean crop at 60 percent good-to-excellent.
There are a few scattered reports of corn starting to dent, but the majority of the crop – 55 percent – is entering the dough stage. That is 10 days behind last year and eight days behind the average.
The majority of the soybean crop is done blooming with 87 percent setting pods, five days behind the average.
August has been slightly cooler than normal by a few tenths of a degree.
“July was just a little bit warmer than normal, so if you take July and August combined at this point in time, it adds up to about normal,” he said.
The real lack of growing degree days goes back to May.
“We ended May about a hundred growing degree units behind and we've never got back to normal,” he said. “What we're in now is a grain fill period. Corn is doing what it can to realize that yield potential.”
It is also a time when it is really up to the plants and the weather. All growers can do is wait and watch.
Things to look out for is stalk and root quality.
USDA is reporting 81 percent of topsoil having adequate moisture, with 7 percent in surplus. Subsoil moisture is estimated at 83 percent adequate and a 9 percent surplus.
“We'd like to see a nice, long grain filling period with daytime highs at about 80-85 degrees and nighttime lows around 55-60 degrees,” he said. “That's when corn really does its best, when it has a good day to get some work done and a little bit cooler night to kind of rest.”
The same is true for soybeans as they move through the pod filling stage.
The looming question over everything is when will that first killing frost hit and if the crops will have had enough time before then.
“Usually, we look at about Oct. 1 as our first frost date. That’s kind of our normal,” said Hoverstad. “I would say if that came Sept. 15, that would be problematic, so we'd like to get to the first of October this year if we could and we should expect that.”