Hot weather stresses crops
By Janet Kubat Willette
Date Modified: 09/25/2013 11:14 AM
POTSDAM, Minn. — In southeast Minnesota, the planting season stretched from May into June, delayed by snow and rain.
Now, too much heat and not enough rain are killing the crop before it's mature.
"The weather is throwing us another surprise," said regional Extension educator Lisa Behnken, speaking at the Olmsted South Wabasha Annual Plot Day on Sept. 10. Slightly more than 100 people attended.
It's disheartening to see soybeans and corn dying, Behnken said. Soybeans are filling pods and she walked into a field adjacent to the picnic tables set up for the plot day to show plants with aborted pods.
All the soybeans in southeast Minnesota were planted in June and they will need September to mature.
For some fields or some field portions, rain now will be too late.
On the corn field on the other side of the picnic tables, Behnken said there was some tipback. A lot of corn in the region was planted after June 1. While growing degree units are ahead of schedule from June through Sept. 9, a good September is needed to finish the bulk of the crop, she said.
They planted 94 to 100 day hybrids May 15 on her farm. The corn isn't done, unless it droughted out, she said. The hot weather cost yield every day.
In Extension plots at Rochester and Rock Dell, 82-day to 102-day hybrids were planted in June. The 99-day variety and later aren't dented yet, but the earlier hybrids are. Once corn reaches dent stage, it will achieve 77 percent of its yield if frost comes. In general, corn needs 30 days after denting without frost to mature. If frost hits corn before it's dented, farmers can generally expect to harvest 40 percent of the corn's potential yield. The corn also will have low test weight.
Behnken expects harvest to be stretched out. Some farmers have started harvesting corn for silage.
Behnken highlighted some of the Extension research happening in the southeastern part of the state. Acorn rootworm plot is on the Sheehan farm south of Rochester and herbicide trials are across from the college in Rochester.
They're seeing a lot of waterhemp escapes and ragweed resistance to glysophate and ALS herbicides. On a site with resistance the products Extension researchers expected to work good didn't. Instead, they saw a flip-flop with herbicide because of the weather.
"You never farm on what was last year," Behnken said.
Weed resistance is an issue. Weeds to watch include not only ragweed and waterhemp, but also Palmer amaranth. Palmer amaranth makes waterhemp look like a pee-wee plant and makes giant ragweed look not that bad, Behnken said.
"You want to destroy that weed," she said.
Palmer amaranth is aggressive and has a much larger seedhead than waterhemp. It has been found in Iowa and Wisconsin and it's epidemic in many southern states.
The weed could come into Minnesota on cottonseed and then infect fields when manure is applied.
There were about 901,600 acres of prevented plant in Minnesota this year, according to the Minnesota Farm Service Agency.
Not only did prevented plant force change in rotations, it also introduced cover crops into fields where cover crops haven't typically been planted.
Behnken said the change in rotations will work in producers' favor for control of corn rootworm.
She's recently noticed that some prevented plant cover crops are being terminated by glysophate. She tried to get a discussion started about why. One farmer volunteered that he's concerned about residue management.
Jill Sackett, an Extension educator and conservation agronomist who works with cover crops, said that in order to get the most out of the money spent on cover crop seed, farmers should leave the crops alone until spring.
"I don't feel there's a reason at all (to terminate now), it defeats the purpose of what a cover crop is doing," Sackett said.
Oats, which were planted in many fields, will be killed by spring tillage or spring-applied herbicides. They will stay green until November, Sackett said. They die off when it's good and cold; they don't survive winter.
There will be less stover from oats than from a corn-on-corn crop, she said. Leaving the cover crop growing into fall benefits soil microbes.
The last two weeks of August into early September is a common time to plant cover crops on non-prevented plant acres.
The issue may be cover crops planted on prevented plant acres are outside a farmers normal rotation and farmers are unfamiliar with how to handle the crops to benefit their soil and other crops, she said.
Rich Bauer, Farm Service Agency county executive director in Dodge and Olmsted counties, said direct and counter-cyclical payments and Conservation Reserve Program payments will be issued in October. Expect a 5 percent reduction in DCP because of the sequester, Bauer said.
If farmers don't get their check by the end of October, they should call the office, he said.
The office is unable to mail things because of budget cuts and requested that farmers give the office their email address so they can receive updates.
He thanked farmers for their patience with the FSA during the busy spring season and reminded them that Nov. 15 is the deadline for certifying hay and fall seeded crops. The late certification fee is $46.