Iowa Public Television


More Gain From Smarter Drain

posted on October 22, 2010

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BP informed a federal judge this week that the embattled company is waiving a $75 million cap on its liability for certain economic damage claims spawned by the April 20 explosion on the Deepwater Horizon rig and resulting oil spill.

Nevertheless, the impact of the tragedy on the environment -- and the Gulf Coast economy -- is unfathomable.

Scientists were already concerned about pollution in the Gulf of Mexico long before the BP debacle. Previously, the issue was an area commonly known as the "Dead Zone," thousands of square miles where oxygen levels are too low to support marine life

Environmentalists blame the hypoxic area primarily on nitrogen-based fertilizers used by farmers in the Mississippi watershed. And the EPA is calling for a 45 percent reduction in nitrogen loads in the Mississippi River by 2015.

But a Midwestern company is helping farmers reduce the amount of nitrates entering the Gulf. By deploying an innovative drainage management system the growers also hope to increase their yields. Andrew Batt explains.

Charlie Schafer, President of Agri Drain Corp: "Often times you'll be with a producer and you'll look at that corn crop curling up from drought stress and you look at the outlet pipe and it's running water and you ask them why they let that happen. Why they let the water go and you usually get one of two answers. Either one I never knew I had a choice. Or, they'll say well I always wondered about that."

Charlie Schafer is president of the Agri Drain Corporation. Over thirty years ago, Schafer and his brothers started the business as drainage contractors, installing tile and doing waterline work. Today they say that while they are not the largest, they are the most complete supplier of water management devices for agriculture.

Charlie Schafer, President of Agri Drain Corp:"It's always been our opinion that we could do a better job of designing and managing drainage systems. My gosh we're steering tractors with satellites and we unlock cars from anywhere in the world and so it seems ridiculous that we wouldn't manage outflow of sub-surface drainage systems."

Primitive tile drainage systems date back to as early as 200BC, but John Johnston is considered the "Father of American Tile Drainage." In 1838, Johnston tiled a marshy, low-lying 10-acre plot on his farm in New York and, with the help of manure for fertilizer, saw his wheat harvest increase from a meager 5 bushels per acre to 50. Today, estimates are that over 50 million acres in the Corn Belt are drained through subsurface tiling. The innovation has enabled an increase in both cropland and yields, but not without a price.

According to a 2008 U.S. Geological Survey report, agriculture in the Mississippi River Basin is 70 percent responsible for nitrogen and phosphorus entering the Gulf of Mexico. Research indicates that the two chemicals are the major contributors to an area of hypoxia in the Gulf known as the "Dead Zone."

Charlie Schafer, President of Agri Drain Corp: "In agriculture nobody wants to be to heavily regulated but again we all want to do the right things and if we can -- if we can truly generate a benefit from a practice that makes so much sense and we can improve water quality downstream than it seems like that's a concept that should move forward."

Schafer believes his business already manufactures a product that could be used to reduce nitrate and phosphorus pollution while increasing yields. It's called a water level control structure, which traditionally has been used to manage levels in surface water such as ponds and wetlands. While Agri Drain has been manufacturing water level control structures for 30 years, the structures have only recently been recognized in the Midwest as a possible means of controlling pollution from sub surface drainage.

The process is fairly simple. Subsurface water flows into the structure through underground tiles. Partitions which are referred to as logs, can be added or removed to increase or decrease the level of the water table behind the structure.

During winter, the water table is raised to store soil moisture and decrease the amount of nitrates and phosphorous being released. In the spring, logs are removed, lowering the water table to make spring fieldwork possible. Once the crop has been planted, logs are added to raise the water table for the growing crop. During the growing season, the water table can be raised or lowered depending on weather conditions. In the fall, the water table can be lowered further. Once the harvest and fieldwork are completed, logs are added and the water table is again raised to near the surface of the soil. The goal of the yearlong cycle is two fold. By increasing soil moisture, crops should do better during the summer when they need water and through a reduction in the amount of water drained there should be less nitrates and phosphorus entering rivers and streams.

Jeff Strock, University of Minnesota: "We've seen about a 50% reduction in water flow leaving the system so that is less water going into the rivers and streams. And we've also seen a reduction of annual loads of nitrogen and phosphorus. We've seen about a 40% reduction in nitrate loads leaving the system and we've seen about a 60% reduction in total phosphorus loads leaving the system."

Jeff Strock, a soil scientist with the University of Minnesota, measures the pollutants leaving farms with water level control structures. While tests showing reduction in nitrate and phosphate levels seem conclusive, measuring drainage management's impact on yields has been difficult. In order for the system work properly, spring rains are needed in order to raise the water table.

Jeff Strock, University of Minnesota: "When we look at the yield benefits in those areas we actually see a neutral to slightly positive increase in yield across these -- these sites at these five different states. We've been a little bit disappointed in those yield responses over that study period but one again needs to realize that, you know, we're at the mercy of mother nature and we've had across the northern corn belt a fairly dry stretch over the last three summers.

But studies conducted on Brian Hicks' farm in southwest Minnesota in 2009 did indicate increased yields are achievable through drainage management. Besides monitoring the effect of controlled drainage on water quality, Hicks has set aside a field for side-by-side yield comparisons.

Jeff Strock, University of Minnesota: "So, we have a side-by-side comparison where we have conventional free drainage and we have control drainage. The control drainage averaged about 223 bushels and the conventionally drained side of the field averaged about 203 bushels. So, we saw about that 10% increase in yield on that particular -- that particular practice in that field."

For Brian Hicks, whose farm has been in the family for four generations, it's a win-win situation: increasing yields while at the same time protecting resources important to farming.

Brian Hicks, Tracy, Minnesota: "As farmers we need to tell our story. We need to show the public that -- that what we're doing out here in Southwest Minnesota, Iowa, Wisconsin, what we're doing out here as producers isn't damaging the environment.

I think we as farmers are -- are probably the first environmentalists. It's in our best interest to make sure that the soil which I consider our factory is performing to the best that it can. So, managing our nutrients, managing our chemicals, it's all -- it's all in our best interest to -- to take care of those -- those assets that we have.

Matt Helmers is an Associate Professor and Extension Ag Engineer at Iowa State University. He's working to raise awareness of the importance of designing drainage systems that reduce or minimize nitrate loss. Helmers believes that while a water level control structure could be part of the solution, it‘s not "a silver bullet."

Matt Helmers, Iowa State University: "I think that, you know, right now we're -- we're working in a frame work of voluntary practices whether that changes into the future we'll probably be dictated by some policy -- potential policy. All of the technologies we have out there have some promise and probably work better in some areas of the landscape than other practices. I think that we need to look at all practices that maybe available to help us maintain economic vitality of our agricultural production but protect those downstream water supplies."

For Market to Market, I'm Andrew Batt.


Tags: agriculture BP disasters economy Energy/Environment Environmental Protection Agency Gulf of Mexico Iowa Mississippi River news oil oil spills pollution water quality