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Mississippi's Battle to Keep Nutrients in Place

This Business of Farming

Recycling irrigation water is one of many strategies in Delta Farming conservation strategies

Published on: May 31, 2012

Chasing down farmers leads me to some fascinating places. This week I got to visit the place where Muddy Waters, one of God's gifts to music and a cherished American blues icon, cut his teeth.

Stovall Plantation, near Clarksdale, Mississippi, happens to be where Waters grew up.Two of his recordings, "Burr Clover Farm Blues" and "Burr Clover Blues," were recorded here. The songs paid tribute to plantation owner Colonel William Howard Stovall (1895-1970) and his crop.

Stovall plantation was also the starting point for this year's Conservation Technology Information Center (CTIC) "Conservation in Action" tour. About 250 farmers, academics and agribusiness folks got together in the heart of the Mississippi Delta to find out what farmers and conservationists are doing to protect soil and water here.

Soil conservation is important everywhere but we quickly learned there's a lot at stake here in the Delta. For one, it's the front line of defense in the growing hypoxia problem in the northern Gulf of Mexico. There's a lot of worry that nutrients from farm fertilizer applications are slipping into the Mississippi River and causing this hypoxic 'dead zone' area to grow.

Starting the tour at Stovall Plantation was a fitting move for CTIC. It seems every tour provides a fantastic historical background. Two years ago we began the CTIC tour at Jamestown,Virginia, site of the first colonial settlers. It's great to think about the history of a place in the context of conserving it for the future.

Stovall plantation has been owned by the same family since the early 1800s, explained Pete Hunter who grows corn, soybeans and wheat and is part owner. This farm had planted cotton for 154 years before switching to other crops six years ago. It was also no-till until multiple weed resistance, led by the dreaded palmer pigweed, start forcing local farmers to rethink tillage and weed control options.

The Delta, comprised of about 3 million acres, is focusing on adopting best management practices to keep soil in place, and none of them, strangely, have anything to do with no-till or cover crops. But that was just the beginning of my southern education.

This part of the world has some of the best topsoil and gets plenty of rainfall – as much as 50 inches a year. The problem is timing. "Most of the rains come in January and February," says local farmer Travis Satterfield. "That's good for ducks, not so much for corn."

Dependent on irrigation

In 1974 the state passed a law that promoted more rice production, ideally suited to the region. "We went from 60,000 acres to 380,000 acres and it all required irrigation," says Satterfield. In that time irrigation went from zero to 80% of the acreage today, and it's still growing. As a result, the alluvial aquifer serving this region is under increasing pressure. "It's scary to say, but now we are totally dependent on irrigation, and we don't want to hear that we will have limits put on how much we can use, so we are attempting to use less through conservation," says Satterfield.

Farmers here are adopting three key practices. First, they level land to slow speed at which runoff escapes fields. They install pads and pipes to channel water through a fixed-elevation conveyance device, which prevents head cutting and cuts sediment losses by 60%. The practices can more precisely control water elevations for crop flooding, if needed for rice, for example; and can store winter water to help wildlife habitat. Permanent pads and pipes can result in highly efficient irrigation and save 0.25 acre-feet of ground water annually.

Many fields also have drainage ditches. "They're not charismatic, you just have to learn how to play with them," says Robbie Kroger, a wildlife and aquaculture professor at Mississippi State University. Kroger says low-grade wiers – a simple batch of small stones placed strategically in the drainage ditches – help filter sediment and nutrients out of runoff. They are looked at as an innovative, yet cost effective, management practice that decreases nutrient concentrations and loads by increasing the water volume and hydraulic residence time of the ditch.

Farmers here are also trying something innovative called "tailwater recovery system," which captures runoff from fields and returns it to be used again. The system requires a series of underground pipes and pumps that move the water back to the fields. While it may not be cheap to install, research shows a 10% improvement in nutrient runoff and 20% reduction in groundwater use from this system.

More and more Delta farmers appear willing to try these practices as they look at increasing concerns over water.

Stovall Plantation has a 7-acre reservoir that can store recovered tailwater. The pond was designed (and partially paid for with NRCS cost-share funds) to provide irrigation water for approximately 133 acres.

"This reservoir will save 50% of the runoff over 10 years," says Paul Rodrique, an area NRCS irrigation engineer. He believes the energy savings from these reservoirs make them a good long term investment. "It's cheaper to pump water 15-feet instead of from a 75-feet deep groundwater well," he explains.  Adds Pete Hunter: "The tailwater recovery and reservoir system has led to better water quality and better water efficiencies."

More important, it can keep those nutrients from slipping downstream in the watershed. "Anything we can do here to reduce the amount of nutrients that go down the river is going to help save the Gulf," adds Hunter.  "One of these days we're going to be limited in how much water we can pump, and a lot of farmers are going to find innovative ways to store water on the farm."

Delta farmers could be singing the blues if they don't adopt practices fast enough for regulators. The dead zone is a constant reminder why these practices must work.