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Study: Meeting RFS Goals for Corn Ethanol Production Will Worsen “Dead Zone” in Gulf of Mexico

11 March 2008

Ramping up the production of corn ethanol to meet the targets set by the new US Renewable Fuel Standard (RFS) will worsen pollution in the Gulf of Mexico, increasing the “Dead Zone”—a growing hypoxic region in the Northern Gulf of Mexico (NGOM)—that kills fish and aquatic life, according to a Canadian-American research team.

Simon Donner of the University of British Columbia and Chris Kucharik of the University of Wisconsin quantified the effect of projected biofuel production on the problem of nutrient pollution in a waterway. Their findings are published in the Early Edition of the Proceedings of the National Journal of Sciences.

The researchers looked at the estimated land and fertilizer required to meet proposed corn-based ethanol production goals. The US Energy Independence and Security Act of 2007 (EISA) mandates, among its many components, an aggressive ramp-up in the use of renewable fuels, culminating in a 36 billion gallon RFS by 2022. Of that, corn ethanol production is capped at 15 billion gallons per year starting in 2015; the remainder is expected to be provided by “advanced biofuels”, the majority of which are cellulosic biofuels. (Earlier post.)

The corn-ethanol goal represents more than three times than triple the production in 2006.

Nitrogen and phosphorus from agricultural fertilizer have been found to promote excess growth of algae in water bodies—a problem that’s common across North America and in many areas of the world. In some cases, decomposition of algae consumes much of the oxygen in the water. Fertilizer applied to cornfields in the central US—including states such as Illinois, Iowa, Nebraska and Wisconsin—is the primary source of nitrogen pollution in the Mississippi River system, which drains into the Gulf of Mexico.

Each summer, the export of nitrogen creates a large “Dead Zone” in the Gulf of Mexico, a region of oxygen-deprived waters that are unable to support aquatic life. Marine species either die or flee the hypoxic zone, so the spread of hypoxia reduces the available habitat for marine species which are important for the ecosystem as well as commercial and recreational fishing in the Gulf. In recent years, it has reached more than 20,000 km2 in size, which is equivalent to the area of New Jersey.

Donner and Kucharik’s findings suggest that if the US were to meet its proposed ethanol production goals, nitrogen loading by the Mississippi and Atchafalaya Rivers to the Gulf of Mexico would increase by 10-34%. Generating 15 billion gallons of corn-based ethanol by the year 2022 will increase the odds that annual dissolved inorganic nitrogen (DIN) export exceeds the target set for reducing hypoxia in the Gulf of Mexico to >95%. To arrive at these figures, Donner and Kucharik combined the agricultural land use scenarios with models of terrestrial and aquatic nitrogen cycling.

The nitrogen levels in the Mississippi will be more than twice the recommendation for the Gulf. It will overwhelm all the suggested mitigation options. This rush to expand corn production is a disaster for the Gulf of Mexico. The US energy policy will make it virtually impossible to solve the problem of the Dead Zone.

—Simon Donner

The results of the study call into question the assumption that enough land exists to fulfill current feed crop demand and expand corn and other crop production for ethanol. The study concludes that increasing ethanol production from US croplands without endangering water quality and aquatic ecosystems will require a substantial reduction in meat consumption.

In October 2007, draft report from the Science Advisory Board (SAB) to the US Environmental Protection Agency (EPA) suggested that changes to the current structure of economic incentives favoring corn-based ethanol may be necessary to prevent a dramatic increase in nutrient loadings in the Mississippi and Atchafalaya River Basin (MARB) that would lead to an expansion of the annual Dead Zone. (Earlier post.)

In October 2007, the US National Oceanic and Atmospheric Administration (NOAA) awarded first-year funding of $284,000 to researchers at the University of Texas at Austin Marine Science Institute (UTMSI) as part of a three-year $781,000 project to develop a better understanding of how nutrient pollution from the Mississippi River affects the Dead Zone in the Gulf of Mexico. (Earlier post.)


March 11, 2008 in Ethanol, Policy | Permalink | Comments (23) | TrackBack (0)


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Corn ethanol politics aside, is it naive to demand that farmers in the corn belt should only use as much fertilizer - preferably from biogas production - as is required and no more?

I read that modern agricultural machinery outfitted with GPS and a GIS database can map yields with high resolution. This information can then be used to apply fertilizer judiciously to avoid runoff.

Nitro pollution is an inherent problem of modern agricultural, the solution is sustainable agriculture techniques, perennial breeds of corn and wheat (to be engineered) or self-nitrogenating corn and wheat (holy grail of biotech).

Another direct negative side effect when corn ethanol production is increased beyond current level.

As more corn (3 times more) will be needed to feed the new ethanol plants, farmers with put more land into production to try to maintain food production level. Fertilizer's use and nutrient runoffs will increase significantly.

As corn demand increase, Canadian farmers from Manitoba and Sask will join in and put more land into active production. This will add more nutrient runoffs into the Mississippi basin and the Gulf of Mexico will get another chemical & nutrient dose.

Heavy production of corn ethanol to keep our oversized ICE gas guzzlers on the road is an unwise decision. Agroculture should be restrited to food-feed production.

There must be better ways to satisfy our ground transportation and HVAC needs.

The American Energy policy remains basically the same ..,
"buy it from others" and "ignore the consequences"

Did we expect the Bush Bunch to suddenly 'get it' ???

To link corn ethanol with fertilizer pollution in the Golf is either based on ignorance or is a product of intentional political propaganda. The following explains why and suggest a solution to the real problem of fertilizer pollution in the Golf of Mexico.

It is a fact that the Golf of Mexico is polluted by fertilizer from agriculture and that this pollution is increasing. It is increasing because the use of fertilizer increases and also because US agriculture production is increasing. This problem will be far worse in the immediate future unless something is done. The reason is that the global prices of pretty much any agricultural products have tripled in the past 3 years. Prices are increasing because of the obesity epidemic and because economic growth has enabled billions of people worldwide to eat meat and fat instead of grain only. You lose from 4 to 40 times the energy when converting grain to meat so it is creating a colossal demand for grain for animal feed when billions chance the way they eat.

The planet produced about 2300 million tons of grains in 2007 see Much more is needed when all Chinese and Indians can finally afford to eat like Americans. That would probably require some 10 to 15 billion tons of grain which is impossible to produce on this planet using standard open land farming. The solution is that the price of grain will go up until many simply can’t afford to eat meat even many Americans that can afford so today. $10 a bushel for corn is not the upper limit in a high growth global world. The reason that it is insane to link the pollution of the Gulf of Mexico to corn ethanol is that corn ethanol >or not< can do absolutely nothing to prevent global food prices from skyrocketing in the future. Even 15 billion gallons of ethanol only requires about 5 billion bushels of corn which is about 125 million tons of corn. This is only about 5% of global grain production. 5% is also about the same as the annually growth rate of the global grain production.

Therefore even if you ban corn production for ethanol it will not prevent prices on corn from going up and the pollution of the Gulf of Mexico to increase in the future. The solution to this problem must target the use of fertilizer so that it is reduced. One way to achieve this could be to tax fertilizer so that it becomes more expensive to use. Simply increase a fertilizer tax until consumption is stabilized on a lower level than today’s consumption and so that the pollution of the Gulf approaches acceptable levels.

With yet another negative side effect of industrial agriculture added to the list which includes: no reduction of greenhouse gases, at best marginal net energy, increased soil erosion, increased pesticide pollution, rising food prices for the poor... it is time we reverse the government mandate. Advocates for energy crops have become mere apologists for a mistaken technology. We should have listened to Tad Patzek and David Pimentel. Even before energy crops, our agriculture was destructive and unsustainable.

We would be more successful in reducing fossil fuel consumption and its negative effects by planting wind turbines and solar panels on farms instead of more corn, and electrifying our economy as described in the SA article "A Solar Grand Plan".


The key technology which allows substantially reduce agricultural run-off of nitrogen and phosphorus components is use of slow-release fertilizers. It is already widespread for example in maintaining lawns, and I bet EPA should more aggressively pursue switch from water-soluble fertilizers to slow- and controlled- release granulated variety.


You have a good point but since slow release fertilizers cost more, farmers will keep using the cheapest one, even if they pollute more.

Profits must be maximized regarless of the polution created.


You also have very good points but worldwide massive corn-grain ethanol production will definately increase active farming areas and the use of fertilizers. It will also contribute to a faster reduction of forest areas to make room for sugar cane-corn-grain-sugar beets-palm oil etc. agrofuel feed stock production.

The maths are very simple. The agro-feedstock required to produce enough fuel for a single monster gas guzzler can feed up to 11 people.

Something will have to give and it should be our ICE gas guzzlers and liquid fueled and gaz HVAC.

Progressive (accellerated) electrification of our ground transportation vehicles + HVAC is not a luxury but a necessity.

We don't have to give up our vehicles or travels but learn to do it differently. Our old sun can supply all the energy required 1000 times over.

Canadaian runoff does not go into the Mississippi basin. Even the red river in MN flows north, not south. The Canadian runoff either goes to the great lakes or the Hudson bay.

The dead zone is a result of poor farming practices over the past few decades. That is, farming for profit on the backs of cheap fertilizers and the expense of the health of the soil. These practices are starting to change. Taxing fertilizers does sound like a good way to force farm practices to use chemicals more efficiently, although rising oil prices will do the same thing, albeit slower and indirectly.

I'm all for electrification of cars, that is 50% of Oil use! Problem is that the other 50% power planes, trucks, trains, ships, makes plastic, asphalt, pharmaceuticals, etc, Even if you could replace trucks, plane, trains and ships with some kind of electic power versions, you still have 15-30% going into making materials, and there is no physically away of converting electricity into matter. So there is a place for biomass after all, existing agriculture waste could replace 15% of oil use, that all plastic and asphalt right there.

@ Henrik -

the point here is that the RFS goal of 15 billion gallons corn ethanol by 2020 encourages farmers to switch from other crops that are less fertilizer-intensive and/or grow additional corn on land that was fallow.

@ Andrey -

slow-release fertilizer would reduce immediate runoff, which may be the primary culprit. However, consistently over-fertilizing with slow-release product would still generate runoff in the long run.

The following videos are from German turnkey provider AgriKomp. The first - in English - explains the components of a biogas production and micro-CHP system for a modern farm. Various feedstocks can be used, e.g. sileage from corn stalks, grass or dung.

The second - in German - zeroes in on a press for the fermentation remainder. It reliably separates the liquid and solid fractions regardless of input composition. Both can be used as fertilizer but the spreader technology is different. The dry solids are a natural slow-release fertilizer product.


If we can reduce fuel consumption to between 15% - 30% of current level with electrification, the potential shortage would be solved for a long time. Existing supply of fossil fuel, such as heavy oil and tar sands etc + sustainable agrofuel production could supply minimum essential requirements for many decades or until such time as sustainable substitutes are produced. By the end of the century we will find a way to indirectly convert sun energy to liquid fuel.


Outside the US there is not much ethanol production left because of rising grain prices. In 2007 the non-us global ethanol production from grain dropped to under 1 billion gallons. It was over 2 billion in 2006. Grain prices is still rising but so is oil and this has increased the price for ethanol so that the US grain ethanol producers are still marginally profitable. I expect grain prices to rise faster than oil in the coming years and therefore I also expect corn ethanol to stop in the US as well. It will be replaced by non-food biomass to ethanol and other alcohols and that together with electric propulsion will enable the US to go carbon neutral in transportation as well.


I get the point and you are right. I imagine that a fertilizer tax would create incentives to use less fertilizer intensive crops or alternative types of corn that use less fertilizer. They keep getting better at manipulating these plants and I am sure a lot can be achieved if there is a tax that internalizes the social cost of using fertilizers.

A little info on the relation between crude oil, ethanol and corn prices and the possibility of maintaining strategic ethanol production capacity as an alternative to the strategic stock of fuel.

If crude oil go to $200 a barrel in about 5 years from now then gasoline will go to 200/42 +1 = $5.76 per gallon in the nearly tax free US. This is still cheap compared to the $7 a gallon we pay in Europe right now. The ethanol price should be able to follow up to about $5 a gallon in that case and that would make ethanol from corn profitable even at about $11 a bushel or twice its current price of $5.5 per bushel. Will crude oil go to $200 a barrel in 5 years? I believe it could and that it even is likely but it is also about the upper price limit for crude oil under the condition that no mayor war breaks out that will disrupt supplies from the Middle East. In a peaceful world I can’t believe that oil will be able to go much higher than $200 a barrel and $5.8 a gallon in the US because the alternatives will come in with force at such a high price.

For strategic reasons the US could keep the production capacity to do at least 15 billion gallons of corn ethanol per year at any time it is needed. The capital cost of corn ethanol factories is very low so it could be a cheap method for the US to maintain the strategic ability to produce transportation fuel in case a big disruptive war breaks out in the Middle East. An event that could happen when and if the US leaves Iraq sometime after the election. In fact the US produces enough corn right now to do 30 billion gallons of ethanol or about 20% of the US gasoline consumption. I would not be surprised if it was much cheaper to keep such a production capability in reserve for grain / sugar ethanol than maintaining the current stock of fossil fuel which will run out anyway after 6 months or so with no imports. Of cause if corn ever dropped in price it could be activated to produce ethanol profitable and thereby also function to partially assure a minimum price for corn.

Apparently its OK to grow corn for human consumption, export, and livestock feed, but its not OK to extract only the starch from 1 out of 5 bushels of corn to make ethanol. The other half of that one bushel of corn produced distillers grains and corn oil, both food related products. Last year, by weight, only 10% of the entire corn crop went to ethanol production. Therefore, 90% of the corn factor contributing to the Algae Bloom at the mouth of the Mississippi was caused by corn Not used for ethanol. Also factor in other non corn causes: All the other types of crops being fertilized with nitrogen and phosphorous, grown in the Mississippi watershed. All the tens of thousands of septic tanks that overflow their sewage effluent into the runoff waters during heavy rains. The hundreds of sewage disposal plants that routinely discharge partially treated sewage effluent into the watershed, laden with nitrogen and phosphorus. Another major source of nitrogen and phosphorus in this watershed is all the effluent run off from hundreds of feed lots, pig farms, dairy farms and poultry farms. It doesnt take a rocket scientist to see that corn ethanol is Not the primary cause of the algae bloom. Likewise, the study referenced above is flawed. Instead of growing more corn, we could simply extract the starch from 2 out of 5 bushels of corn, and still get distillers grains and corn oil out of the other half of the 2 bushels.


Are you 100% sure that some of south Manitoba's and Sask's rivers and streams don't flow south and end up in the Mississippi basin?


As a Minnesotan, I am well aware of my own state. The western portion of northern MN flows in to the red river basin which flows north. The northern border of MN (in the middle)is the boundary waters. The eastern portion is above Superior. From Superior all the way to Maine is the great lakes chain which divide the US from Canada. I'm not aware of any rivers that empty a great lake into the Mississippi. That's what makes Duluth so key. Duluth rail-lines to the twin cities are the only transport connection between the great lakes shipping and the Mississippi shipping. The Mississipi river starts as a small stream in Lake Itaska, MN, about 2/3 of the way up the state.
Everything from Duluth east to Maine is the great Lakes.


Add info
Sustainable corn is possible with similar yields from a 25 year study by some ivy league NE school. You will get an initial drop and then yields will increase and plateau as the soil becomes richer and more fertile and recovers from chemical overuse.

The problem with self nitrogenizing plants is that they too contribute to nitrogen runofff. I did some self-research into tree species that did nitrogen fixation through the roots similar to legumes. They do exist and the problem is that with large plantations is that the runoff is highly nitrogenated and care must be used such as limiting the number of trees and the location. I think therefore, self fertilizing plants, while worthwhile in cutting down external fertilizer use would not really cut down on nitrogen runoff and the subsequent dead zone. We would still need to be careful.

It may be useful if the technology ever comes to use the runoff in algae oil farms or for the recreation of the marshland/wetlands to absorb some of these excess nutrients before they create these toxic conditions in the gulf.

I'm not aware of any rivers that empty a great lake into the Mississippi.
The Chicago river/ship channel empties some water from Lake Michigan down the Mississippi.
Duluth rail-lines to the twin cities are the only transport connection between the great lakes shipping and the Mississippi shipping.
You may want to check Chicago again before you repeat that; the port facilities there would make it very easy to transfer from ship to barge.

Darwin and Eng. Poet:

Please visit this MN site for more details on the upper Mississippi River basin including western Ontario and part of south Manitoba.


Harvey D

URL returns 404.


It's refreshing to hear from a clear-thinking propponent of the ethanol industry. The biased attitudes of the "tree-huggers" offer no logistical alternative to fueling the cars that are on the road now/today. What is the alternative? It would be insane to assume our population will be able to just go out and buy expensive hybrid / electric cars just because it's a "good" idea, especially in today's economy.

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