Farming after a flood
Gene Stevens stood on the front line to help farmers after the floods of 2011 inundated hundreds of farms and hundreds of thousands of acres of cropland up and down the major Midwest waterways. He's a crop specialist with the University of Missouri Commercial Agriculture Program at the Fisher Delta Center in Missouri's far southeast bootheel.
As the water piled up around Cairo, Illinois, the Army Corps of Engineers regretfully blew sections of the levees at the Bird's Point-New Madrid Floodway to pour river water onto 130,000 acres of farmland in this fertile region to save bigger population areas.
Stevens lives and works in the area. Like many other Missouri Bootheel residents, for awhile he feared for the safety of his own home and family. “When they blew holes in the levee at about 10 o'clock one evening, the windows of my house shook like an earthquake had hit,” he remembers.
Fortunately for farmers in that area, the floodwaters also drained off fairly quickly. By late May and early June, farmers in the northern end of the floodway got into fields, assessed damage, and began to think about planting a crop.
That's when Stevens' phone started ringing and callers wanted to know what to do to bring waterlogged fields back into production.
Stevens went to work to find answers to the soil problems. He called upon his expertise in soil chemistry with rice production and on his contacts in that industry, where fields are intentionally flooded three to four months each year.
“The most noticeable issues to fields in the Bird's Point Floodway were rapidly moving water causing gully erosion, sand depositions, road gravel carried into fields, damaged and toppled irrigation pivots, and stray metal in fields,” he says.
Possibly the most severe issue on these fields is sand deposition that can pile up like drifts on top of the soil. “In our area, it was a huge volume of moving water, like the whole Mississippi River coming over the fields,” he says. “It left behind these huge sand deposits. Some of them were as much as 6 feet deep, but most were less than 1 foot.”
The Corps moved some of that sand and used it to fill in holes near the levee breaks. But there's really no way to move and use the volume of sand left behind. So where it is possible, farmers will have to move in with plows and earthmovers to level out the biggest piles and blend it in with the soil underneath. “You have to mix it in; you can't plant a crop in pure sand,” says Stevens.
Of course, while that may make a field plantable, one of the problems in this altered soil is higher sand content with less water-holding capacity. Where the crops are irrigated, it likely will shorten irrigation intervals to only three days, or half of normal on typical silt loam soils.
Plowing may also be needed on these fields to fix another problem – erosion that stripped some soils to the compacted plow pan layer, 6 to 8 inches down.
“Farmers did a lot of fall tillage the previous fall because it was dry, so the loose topsoil was easily stripped away,” says Stevens. “No one anticipated that a major flood was coming.”