Farmer Rod Jorgenson loads up 25,000 bushels of corn on his trailer. He'll haul it to the Al-Corn ethanol cooperative 15 miles away. Over the year he'll sell the co-op 100,000 bushels of corn. When Jorgenson joined the co-op 10 years ago, he sent less than half that amount.
"Right now about 80 percent of our crop goes to the ethanol plant," Jorgenson says. "That's probably larger than a lot of growers in the area."
Jorgenson has a corn-soybean mix planted in his fields, but corn makes up two-thirds of his crop. Gas prices influence ethanol prices, so as a co-op member, Jorgenson is making a nice profit on ethanol. That's prompting him to consider planting more corn. It's a trend across the Midwest.
MORE CORN MEANS MORE FERTILIZER, MORE RUNOFF
Corn is a prima-donna plant. It needs good soil and heavy fertilizer. On average, farmers apply more than 140 pounds of nitrogen fertilizer over an acre of corn. Add 18 inches of rain and farmers are likely to have a good crop. Last year, one acre netted Minnesota farmers 174 bushels of corn.
Gyles Randall, soil scientist at the University of Minnesota's Southern Research and Outreach Center, says corn absorbs a lot of nutrients, but it also leaks about 30 pounds of nitrogen fertilizer per acre. That runs off into creeks through field drainage tiles. As Minnesota farmers plant more corn, they'll need to apply more fertilizer.
"And so if we have a corn, corn, soybean rotation that means we'll be applying fertilizer or nitrogen two out of three years," Randall says. "Or applying manure two out of three years. So there will be more nitrogen input into the system."
More nitrogen on the field means more runoff. When farmers plant corn year after year, the soil becomes clumpy and hard to manage. Randall says farmers will need to till their fields more often. More tilling means more erosion. And erosion increases runoff.
Some of that runoff ends up in Minnesota's rivers and lakes. But Randall says in the southeast, that runoff gets absorbed into the aquifers.
"We will see an upturn in the nitrate concentration in the groundwater, and then we sink our wells into that groundwater," says Randall. "That becomes the drinking water supply for many in this state."
High nitrogen levels cause health problems in children and pregnant women.
The University of Minnesota Department of Soil Water and Climate reports that precipitation in southern Minnesota has increased in some places by as much 25 percent since 1930. Much of that rain falls during thunderstorms, making it too hard and too fast for the soil to absorb. Randall says this also contributes to runoff.
Agriculture, like ethanol, has advanced technologically every year. Some scientists are concerned that despite the advances, a boom in corn and ethanol will mean a bust for the state's water resources.
MORE ETHANOL MEANS MORE WATER CONSUMPTION
Minnesota has 16 ethanol plants. Al-Corn in Claremont used 146 million gallons of water in 2005. That's about the same water used by a small city with 3,000 people, a few Dairy Queens and a movie theater.
Randy Doyal, the CEO of Al-Corn, is a burly man who smiles like a kid in a candy shop when he talks about ethanol. He started working in the ethanol industry in the middle of the 1970s' oil embargo. He says back then, people were just trying to see if they could make ethanol.
"At one time I was really starry-eyed and I thought ethanol would be the solution to everything," Doyal says. "We consume so stinking much oil, it's only going to be a stop-gap effort. But for 25 years it's been a constant learning experience. You get to do things every day to try and make it better, and that's way cool."
Doyal's plant is a co-op. Ten years ago it produced 10 million gallons of ethanol. Then it increased to 35 million gallons. Doyal says he's waiting for approval to increase again, this time to 45 million gallons. That's a four-fold increase, and the majority of its corn comes from less than an hour away.
In Minnesota, about half of all ethanol plants use municipal water for some or all of their water needs. The other half sink their own wells.
All plants are required to comply with the Minnesota DNR and the Minnesota Pollution Control Agency about water consumption and discharge. The MPCA regulates how much and how concentrated discharge water can be. The concentration levels are determined by the water quality of the creek or river being used.
We are watching the water table going down too fast. And we're saying [the ethanol plant is] not going to be sustainable.
Doyal's says Al-Corn uses its own wells to supply the plant, and it cleans and reuses all of its own water.
"This is a water treatment facility for wastewater. (It treats) everything but the sanitary sewer. But all the recovered drain and stuff through the plant we filter it, (reverse osmosis) it and that becomes our boiler feed water, so we use it to boil water in the plant," Doyal says.
For every gallon of ethanol Al-Corn produces, it uses four gallons of water. Most of that will stay at the plant. The water that is released only contains the nitrates, sulfates and other minerals found naturally in the groundwater.
Reusing water is common in ethanol plants, but discharging so little and so cleanly is unusual. When Al-Corn was built, it made an agreement with the MPCA to treat the surface water surrounding the plant as protected. That severely limits what the co-op can discharge.
GEOLOGY PLAYS A ROLE
When a plant is built or expands, operators do need to know where they'll draw their water and where they'll dump it. From a geologic perspective, there are good and not so good places to operate. In addition to Minnesota's 16 ethanol plants, eight more have been proposed and four, including Al-Corn, are hoping to expand.
Most of those new plants are hoping to build west of Mankato along the corn belt, but Dave Leuthe, regional hydrologist for Minnesota DNR Waters, says that portion of the state doesn't have much water. The region isn't a good fit for a high water demand industry like ethanol.
Leuthe pulls out several maps that show the geologic makeup of the state. He points to sandstone layers of aquifers.
"In south central Minnesota there's still some of that, but it's starting to be thinner layers and not as much," Leuthe says. "In southeast Minnesota there are a number of aquifers -- sandstone, limestone layers that hold water -- and there is much more water available in storage."
Leuthe says in the southwest, the aquifers are smaller and don't recharge as well as those in the east. That's because of geology.
Southwestern Minnesota is an ancient, clay sea bed. The region doesn't get a lot of rain, and it takes a long time for water to seep through the layers of clay and loam and recharge those aquifers.
DRAINING THE AQUIFER
That's become a problem for an ethanol plant in Granite Falls. Granite Falls Energy has drained its aquifer by nearly half in less than a year. Leuthe says it's pumping faster than the aquifer can refill.
"They want to expand their operation, and we are currently concerned because we are watching the water table going down, and it's going down too fast," Leuthe says. "And we're saying it's not going to be sustainable. You're taking too much for what's there, and it will put other people out of water and you will not have enough to run your operation."
The Minnesota Pollution Control Agency says Granite Falls has withdrawn its application to expand. It applied to draw water from the Minnesota River and discharge there as well. Company representatives would only say the board of directors is considering the plant's future.
According to DNR officials, unless Granite Falls finds a new water source it will eventually need to shut down. DNR Waters' Dave Leuthe says other plants have had to pipeline water from 10 miles away.
"There is a finite amount of water. So we're running on the edges of -- we have to make some difficult choices," says Leuthe. "So we either get more efficient technology, we get better at recycling dirty water, and using it and treating it, and paying the cost of it. There's still the same amount of water, but what the problem is that we don't have adequate supplies of good quality water left."
Leuthe also says the Granite Falls situation brings up the question of who should get the state's water. Ethanol advocates say the technology will find ways to be more efficient.
Leuthe says he can't say when the southwest's aquifers will go dry and collapse. Nor can he say how much nitrogen and sulfate will pollute waterways or creep into the state's deepest and cleanest aquifers. But he can say he's concerned that there will be a crisis before there is a solution.
Your support matters.
You make MPR News possible. Individual donations are behind the clarity in coverage from our reporters across the state, stories that connect us, and conversations that provide perspectives. Help ensure MPR remains a resource that brings Minnesotans together.