Crop year has been a challenge
WORTHINGTON -- The rain seemed as though it wouldn't stop in the early part of the growing season, and now portions of southern Minnesota are thirsting for moisture.
According to the U.S. Department of Agriculture's crop and weather report issued Monday for Minnesota, topsoil in the state ranked at 7 percent very short, 22 percent short, 64 percent adequate and 7 percent surplus.
Rains on Sunday and Tuesday mornings will certainly help, but more is needed to advance both the corn and soybean crops as they complete their last stages of the growing season.
"We've certainly been lacking in rainfall for some time, and we've had higher temperatures," Liz Stahl, University of Minnesota Extension crops specialist at the Worthington Regional Center. "That higher temperature and lack of moisture really puts stress on the crop."
While those early season rains caused both planting delays and drown-outs, Stahl said they helped to keep moisture in the topsoil for an extended period.
Plants drew on those reserves during the pollination stage, but with shallow root systems in both corn and soybeans, the reserves ran out at a critical time in kernel and seed development.
Soybeans have now reached the R-6 stage, which is when the plants are filling their pods with seed, said Stahl.
"A lot of moisture is used by the crop, so if we're under stress during this time, we could end up with small seed, or the plants could abort the seed, and that has an effect on yield," she added.
As for corn, the ears are filled with kernels that are now starting to dent.
Stahl said kernel depth will be an issue this year because the high heat and lack of rain in July came just as ears were starting to fill.
"We're going to have a lot of areas of shorter (kernel) depth," she added. "There could be some kernels under moisture stress that didn't fill properly or aborted."
Moisture stress is also causing some corn and soybean fields to prematurely turn brown, which Stahl said can also have an impact on yield.
"It takes off that top-end yield," she said, adding that rains earlier this week, in addition to milder temperatures, will help keep many plants from prematurely browning.
As for pests and diseases this year, Stahl said soybean aphid numbers appeared to be lower this year, with not every field reaching the threshold levels where spraying was necessary.
"Compared to other outbreak years, from what I've heard, this was lower than usual," she said, adding that treatment for the yield-robbing bugs has wrapped up for this growing season.
In corn, Stahl received reports of corn root worm in fields where resistant hybrids were planted.
Resistant hybrids also appeared to be no match for water hemp this year, with numerous farmers reporting problems controlling the weed.
Stahl encourages farmers to consider application of a pre-emergence herbicide next year to ward off such weeds.
This year, the real problem came in getting the post-emergence herbicides on to attack weed growth because of the wet weather early in the season.
"Pre-emergence (herbicides) give you a bigger window to get out there," she said.
Goss's Wilt was also found to impact some corn fields in southern Minnesota this year. A relatively new disease -- it was first detected in southern Minnesota in 2009 -- Goss's Wilt is a foliar disease caused by bacteria that produces lesions on leaves.
"It can have a pretty significant impact on yield," Stahl said, adding that not all hybrids are rated for resistance at this point.
Farmers interested in more information about the disease, as well as others affecting their fields, may find more information at www.extension.umn.edu/cropdiseases.
The website also includes information for submitting samples to the University's plant disease clinic.
"It's been a challenging year, I think, overall," Stahl of this year's crop outlook. "We're going to notice that we didn't get the moisture when we all needed it. Even though warm temps moved the crop along, planting date is so key for us -- that's going to play a role for us this year.
"We've had a real extreme of moisture, both excess moisture and not enough moisture later on in the season," she added.