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Resilient Ag Landscapes: When the floodwaters recede, what's the next step in getting your soil back up to snuff?

Tyler Harris, Editor

April 5, 2019

4 Min Read
flooded farm land
AFTERMATH: When dealing with fields affected by flooding, one of the first steps is assessing what you have in terms of sand and silt deposition and removing any excess material.

The toll from this spring's major flood event in Nebraska has been high: Homes flooded. Grain storage facilities destroyed. Livestock lost. Roads and highways washed out. Then there's sand and sediment — and a lot of it.

It's something most landowners or farmers hope they never see in their lifetime, and while the cost may not be as devastating as losing a home or livestock, the road to recovery still is a long one for those dealing with sand and sediment deposition and sheet and rill erosion.

For many, the question is: Where do you start?

"What we're seeing is a lot of erosion in the uplands where water has come off of frozen soil or snowmelt," says Aaron Hird, Nebraska Natural Resources Conservation Service state soil health specialist. “Producers will want to check all those areas out. They're going to need to do some repair work before they can get in the field this spring. A lot of the major flooding damage was isolated to the floodplains. A large percentage have experienced either massive erosion or deposition of debris, sediment and sand."

Dealing with excess

With that in mind, federal funding is available to help Nebraska landowners affected by flooding through the Emergency Conservation Program administered by the USDA's Farm Service Agency.

The ECP program provides federal assistance to help with the removal of sand, sediment or debris, as well as shaping and leveling the land to fix erosion issues and repairing damaged conservation structures as a result of recent floods.

Producers using this program need to have their ECP application approved before starting repairs and keep any bills, receipts and invoices associated with the repairs to validate the cost-share reimbursement. As of late March, 45 Nebraska counties have been approved for the program.

Deadlines vary by county, so producers should check with their county FSA office for information on application deadlines.

Additional sediment isn't always a bad thing. Hird notes it can be a key part of floodplain stratification, with layers of silt, sand and loam. However, it's important to remove excess material first and even out the deposited material so it's uniform across the field. The ECP program can help with this kind of reclamation.

"A farmer would want to decide what sort of material they gained from flooding — is it soil-like, or is it sand?” Hird says. “The addition of sediment over the top of topsoil is actually what makes a floodplain so productive. If it's a kind of black deposit, then it's sediment or organic material or silt. If it's sand material, keep in mind that sand in the seed zone can be detrimental if it's a dry year, especially when irrigation isn't possible, but can be productive if irrigation is available. Sand over the top of clay or a silty loam can actually allow water to infiltrate quickly in the top before infiltrating more slowly into heavier soil below to store water long term."

However, when it comes to redistributing the material evenly across the field, Hird encourages doing so with the least amount of disturbance possible. However, some tillage may be needed for treating critical areas, such as gullies or sand dunes, and for spreading sediment or sand across the field

Keep it covered

If tillage is needed, Hird advises planting a cover crop immediately after to keep the soil covered, especially if the field won't be planted this spring.

Hird notes NRCS can assist in creating cover crop mixes, and cost-share funding is available each year through the Environmental Quality Incentives Program. However, there may be future opportunities for cost-share for cover crops on prevented planting acres where an insured crop couldn't be planted because of flooding.

For farmers planning on seeding cover crops to keep these acres covered, Dan Gillespie, a NRCS no-till specialist who farms near Battle Creek, Neb., says the sooner, the better. In many cases, fields that have been saturated for an extended period have an anaerobic environment where certain soil biology can't thrive. And, cover crops can give soil biology a jump-start.

"Bacteria and protozoa are animals, too," Gillespie says. "They need air to live in the soil. When you have saturated conditions, you have no air for an extended period of time and they begin to die off."

In prevented planting situations, Gillespie notes, cover crops are a no-brainer: When nothing is growing, the soil is exposed to erosion and weed growth. However, for those who want to plant a cover before a cash crop, it's worth considering planting green — or planting a cash crop directly into a standing cover crop — to keep living roots in the ground longer.

"Once you get the cover crop planted and those sugars are exuded from the plant root, the result would be immediate," he adds. "It would start rebuilding the soil biology immediately. It's just a question of how much time the cover crop has had to rebuild the biology before you terminate it."

About the Author(s)

Tyler Harris

Editor, Wallaces Farmer

Tyler Harris is the editor for Wallaces Farmer. He started at Farm Progress as a field editor, covering Missouri, Kansas and Iowa. Before joining Farm Progress, Tyler got his feet wet covering agriculture and rural issues while attending the University of Iowa, taking any chance he could to get outside the city limits and get on to the farm. This included working for Kalona News, south of Iowa City in the town of Kalona, followed by an internship at Wallaces Farmer in Des Moines after graduation.

Coming from a farm family in southwest Iowa, Tyler is largely interested in how issues impact people at the producer level. True to the reason he started reporting, he loves getting out of town and meeting with producers on the farm, which also gives him a firsthand look at how agriculture and urban interact.

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