MINNEAPOLIS, Minn. – Wet growing conditions this year may cause corn stalks to lose their structural integrity and corncobs to drop to the ground before the combines arrive.
Wet soil caused many corn fields to run out of nutrients before the end of the growing season. Those crops can dry down quickly even though the roots are still mired in mud, according to Mosaic chief agronomist Dan Froehlich.
“Stalk quality could be a big issue this fall right across the wet areas of the northern Great Plains and Canadian Prairies,” he said.
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“The crop may be so far along by now that we need to harvest it soon, especially if the stalks are weak. It may seem early to your way of thinking if you only look at the calendar, but it’s not early to the crop’s way of thinking.”
Froehlich said corn might lose a half point of moisture per day in a normal year, depending on weather conditions.
However, severe nutrient shortages caused by this year’s wet summer caused the plants to shut down early. That means they need to be combined early.
Corn can lose up to a point and a half of moisture per day when it is under severe stress at this time of year, even when the roots are standing in mud.
“Yields may not be all that high this year, so if you’ve got a mediocre crop, the last thing you want is to leave a lot of cobs lying in the field,” Froehlich said.
“Ear shanks shrivel up and they’re more susceptible to ear drop. Most hybrids have that resistance built in, but with this much moisture stress, all bets are off.
“The first thing to look for is the fir- ing from the bottom leaves. You get that classic V in the middle of the leaves.”
Froehlich said saturated soil allows secondary pathogens to invade the stalks.
He advised growers to cut some stalks open or pinch them to check for stalk rot. The stalk is hollow if the two sides come together when pinched, and a hollow stalk will fall over in the wind.
“This is the point where you need to apply some of that risk management strategy. You may need to take the crop off a lot sooner, get it in the bin before you lose it and then run it through the dryer.”
He said most growers prefer to wait until corn is down to 21 or 22 percent moisture levels, but that’s a luxury some growers can’t afford this year.
Harvest might have to start when moisture levels are higher than 25 or 26 percent if the crop is losing more than one percent moisture per day.
“You might need to combine corn in October instead of November or December. The alternative is you may end up leaving a lot of corn on the ground,” he said.
“Maybe you’ll have to skip the deer hunting just this one year. I know in some areas like Wisconsin, you don’t dare even mention that option, but you have to decide if that deer is more important than your corn crop.”
Froehlich said the impact of wet soil is also critical in other crops. Roots need the oxygen they find in air spaces to access nutrients. When soil is saturated, roots cannot do their work.
“Rice is the only (cereal) crop I know of that likes wet feet.”
This year’s wet weather has major implications for nutrient inputs next year. He said no one knows for sure how much nutrient is still in the ground, but farmers can measure their yields and do a careful nutrient removal calculation.
“That lets you replace what you know for sure has been removed by the crop. You probably didn’t lose much P and K, and you can probably assume your N is gone, but you can’t be sure of any of that in a year like this. So you need to do soil tests. Even if you tested after the 2009 crop was off, the water changed everything. You need to soil sample again.
“In situations like this, the surprises go both ways. You may have more than you think of some elements and less than you think of others.”
