Alternative Farming Cleans up Water

Although the addition of nutrients to soil helps to maximize crop production, fertilizer can leach nutrients, polluting the water supply. A recent study by researchers at the University of Minnesota shows alternative cropping practices may help to protect the environment by reducing high nitrate levels in surface and ground water caused by conventional fertilizer use.
The team of scientists reports their findings in the July-August 2007 issue of the Journal of Environmental Quality.

Nitrogen is one of the most important elements required in agricultural systems for plant and animal production. While treatment with the correct amount of nitrogen-based fertilizer optimizes crop yield and minimizes environmental damage, too much nitrogen can lead to nitrate loss.

Nitrate, a mobile form of nitrogen, escapes via water that percolates through soils. In regions where subsurface drainage is used to promote crop growth, high levels of nitrates are transported to downstream waters. Nitrate contamination of water can contribute to waters becoming hypoxic and stress aquatic life living downstream.

“The challenge facing industry, farmers, agricultural advisors, and others concerned about the environment is to develop efficient cropping systems that maintain economical production levels while minimizing surface and ground water degradation,” says Jeff Strock, lead author of the study.

In search of ways to reduce agricultural pollution, Strock and others measured tile drainage and nitrate losses under conventional and alternative cropping systems over a three-year period in southwest Minnesota. This study was funded by the USDA-CSREES-National Integrated Water Quality Program.

Researchers categorized conventional farming practices as corn-soybean rotations with inorganic fertilizer application and pesticide usage. Alternative farming practices included organic management practices that incorporated rotation of a variety of crops including corn, soybean, oat, alfalfa, buckwheat, and rye with nutrients supplied from legumes and either fresh or composted manure sources. The study found that alternative cropping systems reduced the amount of water lost in tile drainage by 41 percent compared to a conventional corn-soybean rotation. Alternative farming practices also reduced nitrate-nitrogen losses by between 59 and 62 percent in two out of three years.

“Our data suggests that water quantity and quality could be improved by increasing cropping system biodiversity,” says Strock.

Whether in conventional or organic cropping systems, Strock suggests cropping system biodiversity may be adopted as one of several practices to build a sustainable farm management system that is productive, profitable, and environmentally acceptable.

“There are no silver bullets for solving our water quality problems,” says Strock. “Instead, implementing practices such as cropping system biodiversity, along with refined nitrogen management practices, growing perennial crops in a rotation, cover cropping, and other management practices will help prevent nitrate contamination of our lakes and rivers.”

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U.S Embraces Clean Energy, But Beware Ethanol

Americans and their political leaders are increasingly embracing clean, renewable energy. But a foremost expert on energy and technology is warning against relying on ethanol as a solution.





Only one in fourAmerican voters today believe the United States is doing enough to promote and utilize alternative or "green" technologies and renewable energy sources to reduce U.S. reliance on foreign energy sources, according to a new poll by Zogby International and TechNet's Green Tech Task Force.





TechNet is a bipartisan political network of high tech CEOs promotes the growth of the innovation economy.





The Zogby/TechNet nationwide poll of 1,043 Americans found that 77% ofU.S. voters believe that our nation must do more to promote green technologies like renewable energy sources.



Wind, solar, geothermal, biomass, hydrogen and alternative fuels are all cleaner energy sources.



"The magnitude of global energy and environmental challenges demandsthat we act now to implement a sound energy strategy based on U.S. innovation," says John Doerr, TechNet founder and partner at Kleiner Perkins Caufield & Byers, a leading technology venture capitral firm. "TechNet is committed to working with the president and Congress to reshape our energy future."

Renewable energy has been an area of research in the United States for decades, and maintains a dedicated lab at the National Renewable Energy Laboratory in Colorado.

Leaders in both parties of U.S. government are also increasingly turning to support clean energy as an alternative to U.S. dependence on foreign oil. Burning fossil fuels is also thought to be a major contributor to the carbon emissions blamed for global climate change.

Democrats who now control the the U.S. House of Representatives have passed a bill that would cut subsidies for oil production and impose a "conservation fee" on oil and gas taken from deep waters of the Gulf of Mexico. Funds collected would be steered toward renewable, clean energy sources. President Bush is also said ready in his upcoming State of the Union address to further complain of the U.S. dependence on oil and embrace renewable clean energy.

The Danger of Ethanol






However, ethanol will not be an attractive clean- or renewable-energy solution, says veteran Washington correspondent and energy and technology expert Llewellyn King.



Produced from vegetable matter high in sugar or starch and fermented and distilled to produce fuel, the United States already is producing 5 billion gallons of ethanol a year, King notes in his recent syndicated column. For more than 30 years, King published such publications as The Energy Daily and New Technology Week, and observed keenly developments in ethanol and other clean energies. Full disclosure: I used to work for Llewellyn King as editor of New Technology Week.



King, who remains host of the national public affairs TV show "White House Chronicle," says "President Bush is so taken with ethanol that he wants to expand production to 60 billion gallons a year by 2030."



The growing interest in ethanol is affecting the price of corn, driving up the price of meat, King says.



"Last year, there was a shortage of grain for livestock, and beef prices rocketed. Other dislocations are likely when corn becomes the must-grow cash crop," he writes.



Like others, King believes the United States must wean itself from oil and embrace new technologies -- but not ethanol. He suggests hybrid and all-electric vehicles as a better alternative.



"Not only is there something repugnant about using food for gasoline, but in all probability, it will cause damage to the whole agricultural cycle and to the agricultural economy," King writes. "This way lies madness. And it is shameful that so many environmental organizations, led by the Natural Resources Defense Council, have embraced ethanol—which may save no energy whatsoever."








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MIT Ethanol Analysis Confirms Benefits of Biofuels

Controversy over the benefits of using corn-based ethanol in vehicles has been fueled by studies showing that converting corn into ethanol may use more fossil energy than the energy contained in the ethanol produced. Now a new MIT analysis shows that the energy balance is actually so close that several factors can easily change whether ethanol ends up a net energy winner or loser.

Regardless of the energy balance, replacing gasoline with corn-based ethanol does significantly reduce oil consumption because the biomass production and conversion process requires little petroleum. And further MIT analyses show that making ethanol from cellulosic sources such as switchgrass has far greater potential to reduce fossil energy use and greenhouse gas emissions.
The Bush administration is pushing the use of ethanol as a domestically available, non-petroleum alternative to gasoline. But most U.S. ethanol is now made from corn, and growing corn and converting the kernels into ethanol consume a lot of energy--comparable to what is contained in the ethanol produced. Making ethanol from corn stalks, other agricultural wastes and wild grasses would consume less energy, but the technology for converting them to ethanol may not be economically viable for another five or so years.

Does using corn-based ethanol in place of gasoline actually make energy consumption and emissions go up, as some researchers claim? Why do others reach the opposite conclusion? And how much better would ethanol from "cellulosic" feedstocks such as switchgrass be?
To answer those questions, Tiffany Groode, a graduate student in MIT's Department of Mechanical Engineering, performed her own study, supervised by John B. Heywood, Sun Jae Professor of Mechanical Engineering.

Using a technique called life cycle analysis, she looked at energy consumption and greenhouse gas emissions associated with all the steps in making and using ethanol, from growing the crop to converting it into ethanol. She limited energy sources to fossil fuels. Finally, she accounted for the different energy contents of gasoline and ethanol. Pure ethanol carries 30 percent less energy per gallon, so more is needed to travel a given distance.

While most studies follow those guidelines, Groode added one more feature: She incorporated the uncertainty associated with the values of many of the inputs. Following a methodology developed by recent MIT graduate Jeremy Johnson, she used not just one value for each key variable (such as the amount of fertilizer required), but rather a range of values along with the probability that each of those values would occur. In a single analysis, her model runs thousands of times with varying input values, generating a range of results, some more probable than others.

Based on her "most likely" outcomes, she concluded that traveling a kilometer using ethanol does indeed consume more energy than traveling the same distance using gasoline. However, further analyses showed that several factors can easily change the outcome, rendering corn-based ethanol a "greener" fuel.

One such factor is the much-debated co-product credit. When corn is converted into ethanol, the material that remains is a high-protein animal feed. One assumption is that the availability of that feed will enable traditional feed manufacturers to produce less, saving energy; ethanol producers should therefore get to subtract those energy savings from their energy consumption. When Groode put co-product credits into her calculations, ethanol's life-cycle energy use became lower than gasoline's.

Another factor that influences the outcome is which energy-using factors of production are included and excluded--the so-called system boundary. A study performed by Professor David Pimentel of Cornell University in 2003 includes energy-consuming inputs that other studies do not, one example being the manufacture of farm machinery. His analysis concludes that using corn-based ethanol yields a significant net energy loss. Other studies conclude the opposite.
To determine the importance of the system boundary, Groode compared her own analysis, the study by Pimentel and three other reputable studies, considering the same energy-consuming inputs and no co-product credits in each case.

"The results show that everybody is basically correct," she says. "The energy balance is so close that the outcome depends on exactly how you define the problem." The results also serve to validate her methodology: Results from the other studies fall within the range of her more probable results.

Growing more corn may not be the best route to expanding ethanol production. Other options include using corn stover (the plants and husks that are left on the field), or growing an "energy crop" such as switchgrass. While corn kernels are mostly starch, corn stover and switchgrass are primarily cellulose. Commercial technologies to make ethanol from cellulose are not yet available, but laboratory and pilot-scale tests are generating useful data on processing techniques. So how do cellulosic sources measure up in terms of saving energy and reducing greenhouse gas emissions?

Using her methodology, Groode performed an initial analysis of switchgrass and, drawing again on Johnson's work, corn stover. She found that fossil energy consumption is far lower with these two cellulosic sources than for the corn kernels.

Farming corn stover requires energy only for harvesting and transporting the material. (Fertilizer and other inputs are assumed to be associated with growing the kernels.) Growing switchgrass is even less energy intensive. It requires minimal fertilizer, its life cycle is about 10 years, so it need not be replanted each year, and it can be grown almost anywhere, so transport costs can be minimized.

Groode and Heywood now view the three ethanol sources as a continuum. In the future, cellulosic sources such as corn stover and ultimately switchgrass can provide large quantities of ethanol for widespread use as a transportation fuel. In the meantime, ethanol made from corn can provide some immediate benefits.

"I view corn-based ethanol as a stepping-stone," says Groode. "People can buy flexible-fuel vehicles right now and get used to the idea that ethanol or E85 works in their car. If ethanol is produced from a more environmentally friendly source in the future, we'll be ready for it."

The research was supported by BP America.


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