(Advances in agronomy 105) donald l sparks (eds ) advances in agronomy academic press (2010)

Table 1 continuedThe 9 billion gallons of corn ethanol that were produced last year reduced gasoline and diesel consumption of the United States by all of 0.8%, when the fossil fuel that

Advisory Board

PAUL M BERTSCH

University of Kentucky

RONALD L PHILLIPSUniversity of MinnesotaKATE M SCOW

University of California,

Davis

LARRY P WILDINGTexas A&M University

Emeritus Advisory Board Members

JOHN S BOYER

University of Delaware

KENNETH J FREYIowa State UniversityEUGENE J KAMPRATH

North Carolina State

University

MARTIN ALEXANDERCornell University

Prepared in cooperation with the

American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America Book and Multimedia Publishing Committee DAVID D BALTENSPERGER, CHAIR

SALLY D LOGSDON

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First edition 2010

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10 11 12 10 9 8 7 6 5 4 3 2 1

Numbers in Parentheses indicate the pages on which the authors’ contributions begin.

Volume 105 contains six outstanding reviews dealing with nutrient cycling,soil and water resources, climate change, and crop management.Chapter 1

is a thought provoking commentary on the impacts of biofuels on ability of soil and water resources.Chapter 2discusses the potential effect ofbiochar on climate change and carbon cycling, crop productivity, andresource management

sustain-Chapter 3 is a thorough review on water pollution from intensivelymanaged grasslands Pollution pathways and ways to minimize contamina-tion from them are also discussed.Chapter 4is a contemporary review onthe use of an innovative GIS Nitrogen Trading Tool for conserving andreducing nitrogen losses in the environment.Chapter 5discusses the impact

of harvest index variability of grain crops on carbon accounting, withapplication to Australian agriculture.Chapter 6deals with the role of seedecology in enhancing weed management in the tropics

I appreciate the excellent reviews of the authors

DONALDL SPARKS

Newark, Delaware, USA

ix

Are Biofuels Antithetic to Long-Term Sustainability of Soil and Water

3.5 Bioenergy and biofuel potential on a global scale 21

Advances in Agronomy, Volume 105 # 2010 Elsevier Inc ISSN 0065-2113, DOI: 10.1016/S0065-2113(10)05001-7 All rights reserved.

* Assistant Director for Research, Norman E Borlaug Institute for International Agriculture, Texas A&M University System, College Station, Texas, USA

{ Professor of Crop Physiology, Texas A&M University System, College Station, Texas, USA

1

production in Brazil, it seems unlikely that ethanol production from crops will be economically viable without government support Less is known on cellulosic feedstock economics because there are no commercial-scale plants Natural resources that may be affected include soil, water, and air In the United States, agricultural intensification has been associated with greater soil conservation, but this depended on retaining residue that may serve as cellulosic feedstocks The ‘‘water footprint’’ of bioenergy from crops is much greater than for other forms of energy, although cellulosic feedstocks would have a smaller footprint Most studies have found that first-generation biofuels reduce greenhouse gas emissions 20–60%, and second generation ones by 70–90%, if effects from land-use change are excluded But land-use change may incur large carbon losses, and can affect ecological preservation, including biodiversity Social justice is by far the most contentious sustainability issue Expanding biofuel production was a major cause of food insecurity and political instability in 2008 There is a large debate on whether biofuels will always contribute to food insecurity, social justice, and environmental degradation in poor countries.

1 Introduction

The cacophony of responses to a recent New York Times article (NYT,2009a,b) in which New Mexico Senator Bingaman suggested furthergovernment help for the ailing ethanol industry illustrates what an emo-tionally and politically charged topic that biofuel has become (Table 1) Onecan find similar spirited exchanges on biofuel articles at the Christian ScienceMonitor, The Economist, and other newspapers Some of the hot button issuesthat biofuels and especially ethanol raise include patriotism, pro- and anti-war sentiment, terrorism, xenophobia, engine and conversion efficiencies,food for the poor, environmental protection, fair trade, energy indepen-dence, urban vs rural America, big oil companies, and governmentspending of taxpayers’ dollars

How can scientists possibly make sense of this when, after all, theythemselves are not free from partisanship (Clair, 2009; Guston et al.,

2009)? There is not even a strong consensus within the scientific nity on whether the overall energy output from ethanol and biodieselproduction is greater than the input (Liska et al., 2008; Pimentel andPatzek, 2005) Add to that all the other sociopolitical aspects, and onetruly has a (metaphorically) volatile mixture

commu-Because of the many biophysical but especially sociopolitical ties and complexities involved, it should come as no surprise that, whetherfor good-faith or simply politically motivated reasons, there are manycontentious views on the topic of biofuels and sustainability In large part,the topic is linked with that of global climate change, which itself is

uncertain-Table 1 Posted reader comments to New York Times article on proposed increased support to the ethanol industry (NYT, 2009a,b)

I think this is a terrible idea, every single subsidized program has been a terrible money draining failure from airlines to welfare Basically we’re supporting high commodity prices by pushing this plan This hurts foreign competition and disrupts food markets, we should not be burning food until we can end world hunger Of course there are also various environmental concerns, the increased fertilizer runoff, by-products from factories and the stuff is less safe than gasoline since it is less stable.

The claim that the problems of the ethanol industry are attributable to the recession is dishonest The ethanol industry is in terrible shape because corn ethanol makes no sense economically or environmentally, and there is no known method for producing cellulosic ethanol on a commercial scale Please do not prop up corn ethanol The environmental consequences of growing so much corn conventionally (read mono-crop, petroleum intensive, chemical dependent agriculture) easily cancel out the benefits

of ethanol blends Because we heartlessly treat food as a global free market commodity exposed to the whims of speculation, ethanol production has spiked corn prices and in classic domino effect caused the prices of other staples to ride a roller-coaster as well This has led to wide spread hunger, food riots and instability Congressmen, many of whom are deep in the pocket of mega-agribusiness, need to step back for a moment and realize the dangerous consequences of burning food as fuel.

Contact your Senators and Representatives and tell them that corn ethanol fuel is a terrible idea both for the economy and the environment.

Wow! You mean the government mandated something without making sure

it was technologically and economically feasible first?

Ethanol uses up as much fuel as it is supposed to save or more, according to recent studies It makes us more dependent to foreign oil, raises food prices, reduces gas mileage and engine performance, damages the environment If

it wasn’t for .lobbyists, congress would have never given those multibillion dollar corporations our tax dollars to subsidize this lunacy Corn-based ethanol is the ONLY renewable fuel that is available today and is the foundation for the next generation ethanol (cellulosic) of tomorrow The notion that corn-based ethanol being the culprit for increased food prices has been completely debunked, leaving the GMA and other antiethanol groups with absolutely no credibility America’s corn growers have just completed one of the largest harvests of corn in our country’s history, with an average of 154 bushels of corn per acre With continued improvements in agriculture, that yield is expected to double, ON THE SAME AMOUNT OF LAND, over the next decade This country MUST continue to support corn-based ethanol to get to cellulosic and, more importantly, to reduce our addiction to foreign oil.

(continued )

Table 1 (continued)

In addition to the economic failure of corn ethanol, the environmental costs include using limited water supplies Ethanol plants are more water efficient than they were, but still have huge water requirements According to the Feb 2007 Ethanol Producer Magazine it takes 150–300 million gallons of water to produce 100 million gallons of ethanol When the water tables are depleted and we cannot get water for food crops, drinking and other activities, where are the tankers of water going to come from?

I love how 99% of the people bashing ethanol have never driven a car with ethanol (besides E10), but will quickly attest to how terrible it supposedly is

by pointing to bogus studies that use ethanol data in excess of 5 years old Besides, I’d rather buy my fuel from Farmer Bob down the road than some sheik in the mideast that’s funneling money to terrorist organizations The price difference makes up for your lost mileage because of very large subsidies and indirect costs that are paid by other consumers and taxpayers.

If you want to pay more money to Farmer Bob for ethanol, then by all means do so—but pay him with your own money, not money confiscated from others And while you’re at it, add on a few bucks per gallon for the environmental damage that you’re inflicting In short is it not the myth of

‘‘renewable, corn base ethanol’’ that both science and the market place has debunked?

Ethanol from corn is not renewable because the energy inputs are roughly the size of what you get out in usable liquid fuels, and the greenhouse gas savings are nil There is no scientific doubt about these statements, the literature is full of them There is also no doubt that cellulosic ethanol, if made right, or the kinds of advanced biofuels Berkeley, Stanford and other institutions are working on, MIGHT give true relief on the oil front and the

CO 2 front But no responsible scientist, economist or politician (oxymoron) believes cellulosic ethanol or any other biofuel will be cheap, even compared to $100/bbl oil, when all the costs are counted.

I challenge you to forego the tax subsidies and shift to a tax on oil, and a tax on carbon, and let the market decide how well ethanol from corn can compete with other fuels, more efficient cars, and less driving.

Corn also requires nitrogen fertilizing that is being blamed for increasing dead zones in the Gulf of Mexico and elsewhere If we want to get more than 10% of our vehicle fuel from corn etc serious inroads in land and water needed for food crops will have to occur Biofuels are just recycling carbon dioxide without removing on balance one molecule of that gas already at levels causing major global warming effects So biofuels really are just a wheel spinning operation going nowhere in getting control of climate change

The modern-day definition of agriculture can be said to be ‘‘the process of turning oil into food.’’ Therefore we CANNOT base new generation fuels

on conventional modern agriculture.

Table 1 (continued)

To be optimistic, the goal of the work in Berkeley is to follow the advice Sean gives above, namely to find a way to turn cellulose into sugar and alcohol, just like termites or other organisms do it, without using large quantities of land or water Using basic biochemistry there is a good prospect we can do this, but not necessarily cheaply The late Prof Alex Farrel was a strong corn ethanol until he and his students here started churning out the disappointing numbers on the low energy yields, the huge land, fertilizer and water impacts of corn, and the lack of any greenhouse gas benefit While there certainly is promise of higher corn yields per acre, how much of that increase comes at the expense of greater use of oil products for our mechanized agriculture and coal-based electricity for irrigation? One of Alex’ last articles was an Op Ed in the SF Chronicle about a year ago, entitled ‘‘not more biofuels, better biofuels.’’ Until we get there, we should not be subsidizing and earmarking any biofuels, particularly as all of these questions come up about the costly indirect or side effects of plowing so many acres for corn ethanol.

If for no other reason, we need to support the sale of ethanol because it replaces foreign oil I would challenge all of you to read, read, read Start with Energy Victory by Robert Zubrin Turn three pages on this book about the Saudis and you will never doubt the need for ethanol and alternative fuels Forget that it creates jobs, is good for the environment,

or supports our agriculture economy, or that you hold ethanol to a standard much higher than gasoline Forget all that Read something that sends chills down your spine about the world we live in and the role foreign oil now plays.

Every gallon of ethanol produced and consumed are dollars that stay in America It reduces our dependence on foreign oil, helps our environment, saves American’s money with reduced fuel costs and puts money in the pockets of American farmers instead of Middle Eastern Oil Czars Farmers produce more corn each year as needed for food and fuel Ethanol is the most successful biofuel we have at our disposal today Supporting and using Ethanol today will lead us to the second generation biofuels evolving in the industry Cut out Ethanol and the farm economy collapses Our mid-western economy is balanced on the success of the Ethanol industry Keep it strong and we all succeed So far the only plants

to my knowledge that have closed are the VeraSun plants as a result of some poor commodities buying by their personnel We have an Ethanol plant in our town Green Plains Renewable Energy that is going strong and profitable and is working on second generation biofuels One bad apple does not spoil the whole bunch There should be no regulatory caps on production of Ethanol and standards already set should be kept in place Higher blends should be encouraged by our government It’s the right thing

to do for our country, the environment, and our economy.

(continued )

Table 1 (continued)

The 9 billion gallons of corn ethanol that were produced last year reduced gasoline and diesel consumption of the United States by all of 0.8%, when the fossil fuel that was used to produce the ethanol is taken into account Corn ethanol is not an energy program and never was It is a political largesse program that has hindered the meaningful development of alternative fuels If you are truly serious about developing alternative transportation fuels, the first thing you would do is eliminate corn ethanol subsidies and mandates.

Corn is cheap roughly $4 for 56 lbs We should be embarrassed that

56 lbs of corn can be purchased for $4 The Corn Producers worth their tails off and some people bitch and moan at paying $4 for 56 lbs of corn .! We have so much corn we continue to pay Farmers to NOT grow corn.

It really boils down to who do you want to support (send you money too) Iran

? Bin Laden and his minions? or keep more of our Money and Pride at home supporting America Farmers, American Producers and American Consumers .

There are two commercial cellulose ethanol plants under construction in Georgia (Range Fuels) and Florida (Coskata) These use any organic substance to produce ethanol The producer cost per gallon of ethanol should approach $1.00 a gallon! Your Governmental EPA in 2005 produced a study showing E30 (30% ethanol blend) could produce engine efficiency far superior to plain old gasoline engine efficiency Yes, that means higher fuel mileage on E30 than that gasoline Did you know the largest oil reserve in the world in the Mid-East, uses massive amounts of water to get it out of the ground! If you do not think oil (companies) receive tax breaks that amount to billions of dollars, you are dreaming This amount of amount of money far surpasses what ethanol receives Remove this and a gallon of gasoline will approach $10 a gallon

Well, ‘‘Voice of Reason’’ we need about 0.3/4s of a gallon of that imported petroleum to make 1 gallon of corn ethanol .not a good deal at all when you consider additionally that soils and water were used to grow the corn Additionally the use of the corn kernels for fuel rather than food distorts global food markets.

Ethanol has been a blessing for the small independent farmer and all Americans The government can now subsidize an industry that would not be transferred overseas People have forgotten the gas shortage in the 1970s and the control OPEC had over our nation I even question the control the large oil companies have over our nation Believe me the oil company executives were receiving their multimillion dollar bonuses in

2007 The ethanol industry will take decades to refine production POET Biorefining in Emmetsburg Iowa is now producing ethanol commercially using corn cobs, but it is a process that needs America’s support to get on its feet Ethanol may not be the best long-term alternative fuel source but it is

complex, politically and emotionally charged, and filled with uncertaintyand contention (IPCC, 2008—see Key Uncertainties).

Before launching into some of the more contentious issues, however,some relevant historical points will be made, followed by an overview ofbiofuels

2 Some History

2.1 Ethanol as a fuel

The timeline in Table 2 from the US government’s Energy InformationAdministration (EIA, 2009) allows us to extract some relevant historicalhighlights:

Ethanol has been used to power internal combustion engines since the1800s, including that of Henry Ford’s first automobile The famousmodel T, first produced in 1908, ran on ethanol, gasoline, or a mixture

of the two In the 1930s, more than 2000 gasoline stations in the USMidwest sold gasohol, which contained 6–12% ethanol

Since the civil war, the economic viability of ethanol has been influenced

by government policy, including taxes and subsidies The model T cameinto production 2 years after the government repealed a $2 per gallonexcise tax on ethanol that had been in place for more than 50 years.The Energy Tax Act of 1978 amounted to a 40 cents per gallon subsidyfor every gallon of ethanol blended into gasoline; this was later increased

to 50–54 cents In the 1980s, congress enacted many tax benefits forethanol producers and blenders Government loans and price guarantieswere also offered, and tariffs were imposed on imported ethanol Despiteall these supports, more than half went out of business by the mid-1980s

of corn Have some faith in our technology Farmers are continuing to produce more grain on the same amount of acres using fewer inputs, and ethanol production is branching out to cellulosic production.

Table 2 Timeline of ethanol use in the United States

1826 Samuel Morey developed an engine that ran on ethanol and

turpentine.

1860 German engine inventor Nicholas Otto used ethanol as the fuel

in one of his engines Otto is best known for his development of a modern internal combustion engine (the Otto Cycle) in 1876.

1862 The Union Congress put a $2 per gallon excise tax on ethanol

to help pay for the Civil War Prior to the Civil War, ethanol was a major illuminating oil in the United States After the tax was imposed, ethanol cost too much to be used this way.

1896 Henry Ford built his first automobile, the quadricycle, to run

on pure ethanol.

1906 Over 50 years after imposing the tax on ethanol, Congress

removed it, making ethanol an alternative to gasoline as a motor fuel.

1908 Henry Ford produced the Model T As a flexible fuel vehicle,

it could run on ethanol, gasoline, or a combination of the two.

1917–1918 The need for fuel during World War I drove up ethanol

demand to 50–60 million gallons per year.

1920s Gasoline became the motor fuel of choice Standard Oil began

adding ethanol to gasoline to increase octane and reduce engine knocking.

gasoline stations in the Midwest sold gasohol, which was gasoline blended with between 6% and 12% ethanol 1941–1945 Ethanol production for fuel use increased, due to a massive

wartime increase in demand for fuel, but most of the increased demand for ethanol was for nonfuel wartime uses.

materials and with the low price of fuel, ethanol use as a fuel was drastically reduced From the late 1940s until the late 1970s, virtually no commercial fuel ethanol was available anywhere in the United States.

1974 The first of many legislative actions to promote ethanol as a

fuel, the Solar Energy Research, Development, and Demonstration Act led to research and development of the conversion of cellulose and other organic materials (including wastes) into useful energy or fuels.

Ethanol becomes more attractive as a possible octane booster for gasoline The Environmental Protection

Table 2 (continued)

Agency (EPA) issued the initial regulations requiring reduced levels of lead in gasoline in early 1973 By 1986

no lead was to be allowed in motor gasoline.

1978 The first time gasohol was defined, it was in the Energy Tax

Act of 1978 Gasohol was defined as a blend of gasoline with at least 10% alcohol by volume, excluding alcohol made from petroleum, natural gas, or coal For this reason, all ethanol to be blended into gasoline is produced from renewable biomass feedstocks The Federal excise tax

on gasoline at the time was 4 cents per gallon This law amounted to a 40 cents per gallon subsidy for every gallon

of ethanol blended into gasoline.

Amoco Oil Company began marketing commercial alcohol-blended fuels, followed by Ashland, Chevron, Beacon, and Texaco.

About $1,000,000,000 ($1 billion) eventually went tobiomass-related projects from the Interior and Related Agencies Appropriation Act.

1980–1984
First US survey of ethanol production was conducted.

The survey found fewer than 10 ethanol facilities existed, producing approximately 50 million gallons of ethanol per year This was a major increase from the late 1950s until the late 1970s, when virtually no fuel ethanol was commercially available.

Congress enacted a series of tax benefits to ethanolproducers and blenders These benefits encouraged the growth of ethanol production.

The Energy Security Act offered insured loans for small ethanol producers (less than 1 million gallons per year), up

to $1 million in loan guarantees per project that could cover

up to 90% of construction costs on an ethanol plant, price guarantees for biomass energy projects, and purchase agreements for biomass energy used by federal agencies.

Congress placed an import fee (tariff) on foreign-produced ethanol Previously, foreign producers, such as Brazil, were able to ship less expensive ethanol into the United States.

The Gasohol Competition Act banned retaliation againstethanol resellers.

The Crude Windfall Tax Act extended the gasoline blend tax credit.

ethanol subsidy to 50 cents per gallon.

(continued )

1988
Ethanol was first used as an oxygenate in gasoline Denver,

Colorado, mandated oxygenated fuels (i.e., fuels containing oxygen) for winter use to control carbon monoxide emissions.

Other oxygenates added to gasoline included MTBE (methyl tertiary butyl ether—made from natural gas and petroleum) and ETBE (ethyl tertiary butyl ether—made from ethanol and petroleum).

MTBE dominated the market for oxygenates.

1990
Omnibus Budget Reconciliation Act decreased the ethanol

subsidy to 54 cents per gallon of ethanol

Ethanol plants began switching from coal to natural gas forpower generation and adopting other cost-reducing technologies.

An expanding market and the high cost of fructose corn syrup encouraged expansion of wet mill plants that produce the syrup as a by-product of the ethanol production process.

1992
The Energy Policy Act of 1992 (EPACT) provided for two

additional gasoline blends (7.7% and 5.7% ethanol) It defined ethanol blends with at least 85% ethanol as

‘‘alternative transportation fuels.’’ It also required specified car fleets to begin purchasing alternative fuel vehicles, such as vehicles capable of operating on E-85 (a blend of 85% ethanol and 15% gasoline) EPACT also provided tax deductions for purchasing (or converting) a vehicle that could use an alternative fuel such as E-85 and for installing equipment to dispense alternative fuels.

The Clean Air Act Amendments mandated the winter-timeuse of oxygenated fuels in 39 major carbon monoxide nonattainment areas (areas where EPA emissions standards for carbon mioxide had not been met) and required year-

nonattainment areas in 1995.

MTBE was still the primary oxygenate used in the UnitedStates.

Table 2 (continued)

extended to ethanol blenders producing ETBE.

The EPA began requiring the use of reformulated gasoline year round in metropolitan areas with the most smog 1995–1996 With a poor corn crop and the doubling of corn prices in the

mid-1990s to $5 a bushel, some States passed subsidies to help the ethanol industry.

flexible-fueled vehicle models capable of operating on E-85, gasoline, or both Despite their ability to use E-85, most of these vehicles used gasoline as their only fuel because of the scarcity of E-85 stations.

gradual reduction from 54 cents per gallon to 51 cents per gallon in 2005.

gasoline because traces of it were showing up in drinking water sources, presumably from leaking gasoline storage

alternatives to MTBE as an oxygenate in gasoline, these bans increased the need for ethanol as they went into effect.

nationally.

2001 A 1998 law reduced the ethanol subsidy to 53 cents per gallon

starting January 1, 2001.

E-85-capable vehicles to meet federal regulations that require a certain percentage of fleet vehicles to be capable

of running on alternative fuels Over 3 million of these vehicles were in use.

At the same time, several States were encouraging fuelingstations to sell E-85.

With only 169 stations in the United States selling E-85,most E-85 capable vehicles are still operating on gasoline instead of E-85.

2003
A 1998 law reduced the ethanol subsidy to 52 cents per

gallon starting January 1, 2003.

As of October 2003, a total of 18 States had passedlegislation that would eventually ban MTBE.

California began switching from MTBE to ethanol to make reformulated gasoline, resulting in a significant increase in ethanol demand by midyear, even though the California MTBE ban did not officially go into effect until 2004.

(continued )

A new round of bankruptcies is occurring today (Economist, 2009; NYT,2009a,b).

The demand for ethanol has long been influenced by the supply anddemand for gasoline Demand for fuel and therefore ethanol rose dramat-ically during World War I, and fell drastically after World War II, whenthere was reduced need for war materials and plentiful supplies of cheapgasoline From the late 1940s until the late 1970s, virtually no commercialfuel ethanol was available anywhere in the United States Until 1972,Americans were accustomed to expanding energy consumption withlittle concerns about supply or sharp price increases (Hakes, 1998)

When gasoline prices have become high due to strong demand orconstricted supply, government policies have strongly supported thedevelopment and production of ethanol The legislative actions to pro-mote fuel ethanol in 1974, for example, were in response to turmoil in

1973, which began with electricity brown outs and rapidly rising pricesfor fuel, food, and other necessities Then, an oil embargo was imposed

in October 1973 on the United States by members of the Organization ofArab Petroleum Exporting Countries, cutting further into the supply

of oil and elevating prices to levels previously thought impossible

Table 2 (continued)

2005 The Energy Policy Act of 2005 was responsible for regulations

that ensured gasoline sold in the United States contained

a minimum volume of renewable fuel called the Renewable Fuels Standard The regulations aimed to double the use of renewable fuel, mainly ethanol made from corn, by 2012.

expanded the Renewable Fuels Standard to require that

36 billion gallons of ethanol and other fuels be blended into gasoline, diesel, and jet fuel by 2022 The United States consumed 6.8 billion gallons of ethanol and 0.5 billion gallons of biodiesel in 2007.

An Argonne National Laboratory study compared data dealing with water, electricity, and total energy usage from 2001 and 2006 During this period, America’s ethanol industry achieved improvements in efficiency and resource use while it increased production nearly 300%.

7.2 billion gallons, with an additional 6.2 billion gallons of capacity under construction.

From EIA (2009)

(Hakes, 1998) About $1 billion was invested then by the US governmentinto conversion technologies.

Over the past several years, remarkable gains have been made in bothefficiency of conversion processes and production capacity

2.2 Soil and oil

Soon after the energy crisis, the soil physicist C.H.M Bavel (1977)notedthat the United States was importing $36 billion worth of oil per year andexporting $23 billion of agricultural products, mostly grain and soybeans.The bounty of our farms, he argued, was supporting and extending theprofligacy of our energy consumption He also wondered whether theproduction levels at the time of wheat, corn, and soybean could be main-tained, particularly in view of very high rates of soil erosion Van Bavel(1977)cited a 1971 analysis suggesting that unrestricted land use, includingexpansion of agriculture into marginal lands, could lead to a national soil lossrate of 20 metric tons per ha, which at the time was seen as twice as high asthe maximum tolerable rate In effect, he argued, we were exporting several tons

of soil to the Gulf of Mexico for every ton of grain exported to offset our energydemand This amounted to a bad trade of soil for oil

2.3 Charting our future in the past

In the late 1980s, soon after US legislation began mandating the addition ofoxygenates in gasoline, which in effect increased demand for ethanol, thenASA president E.C.A Runge (1990)pointed out a fundamental dilemmathat USDA’s supply control programs and the potential of ethanol fromcrops presented for agricultural scientists:

We are supposed to develop the technology that keeps US farmers petitive, but we aren’t supposed to create the technology that creates a surplus for the secretary of agriculture to deal with Obviously, you can’t have one without the other It is this surplus agricultural production which has negatively impacted agriculture and agronomists, in particular, for the past decade Can we create a demand for this excess agricultural production?Even then, there were detractors of mixing ethanol into fuels.Runge(1990) cited one author who suggested that ‘‘gasohol’’ would not beeconomical until crude oil reached $60 per barrel Runge (1990) arguedthat whether ethanol production was economically viable depended on thecomparison made and the technology assumed, and that if the cost ofethanol production was compared with the cost of USDA’s supply controlprograms, the ethanol alternative was very economical

com-He reasoned further that, because a very large percentage of our cropsare grown under rainfed conditions, we cannot predict agricultural supply

Therefore, government policy must opt for more than enough crop duction during average or normal weather years to see us through droughtyears, when production is below average That is, excess crop production isthe norm rather than the exception, and supply control policies wouldalways be out of phase with need if weather is a variable.

pro-Runge (1990)proposed that ethanol be used as a ‘‘sink’’ for any excesscrop production rather than utilizing acreage reduction programs, exportenhancement programs, etc., to control supply He calculated that we couldhave saved nearly a billion dollars by converting the corn that we wereexporting in 1987 to ethanol instead Other positive aspects of such a policyincluded increased gross domestic product, rural development, improved airquality, CO2reduction, and revenue enhancement at the local, state, andfederal levels

But Runge also stressed that we must have a US agriculture that is notonly enhanced by science but in harmony with environmental and humanvalues He called for policies that would create a favorable climate forinvestors and companies to design plants to use this excess production,pointing out that there would be little investment if there were no assuredsupply or unstable prices of the raw materials needed to run their plants.Even 20 years ago, ethanol production technology was changing rapidly,leading Runge (1990) to predict that the positive energy contribution ofethanol produced would increase dramatically in the next few years withstate-of-the-art plants

Runge’s (1990)goal of sustainably utilizing our agricultural enterprise toits maximum included a vision of cooperation between US agriculture, theenergy industry, the motor fuels industry, and environmentalists to solveour problems of air quality, greenhouse gas emission, energy imports, andagricultural and rural development problems He believed that the bene-ficiaries of this cooperative effort would include US agriculture, and agri-cultural scientists who provide progrowth technologies for US agriculture.But the main beneficiaries would be US citizens because of a revitalizedrural economy, increased GDP, and improved air quality

3 An Overview of Biofuels1

Biofuels contain energy derived from biomass produced through thecapture of solar energy through photosynthesis A wide range of biomasscan be used to produce several forms of biofuel Sources of biomass includewaste from food, fiber and wood industrial processes, and any number of

1

agricultural and forestry products Biomass can be used to generate ity, heat, power, fuel, and other forms of bioenergy Because the primarysource of energy is solar (even if animal products are used), biofuels are seen

electric-by many as a form of renewable energy

Biofuels can be in the form of solid, liquid, or gas They can also beclassified as primary (i.e., unprocessed) or secondary (i.e., processed).Primary biofuels are directly combusted, usually for cooking, heating, orelectricity production needs in industry.2 Secondary biofuels can be solid(charcoal or wood pellets), liquid (ethanol, biodiesel, or bio-oil), or gaseous(biogas or hydrogen) Secondary biofuels can be used for a wider range ofapplications, including transport and high-temperature industrial processes

Of course, the strongest growth in recent years has been in secondary liquidbiofuels for transport, which are mostly produced using agricultural andfood commodities as feedstocks The most important of these are ethanoland biodiesel (FAO, 2008)

3.1 Ethanol

Ethanol produced for biofuel today is based on feedstocks containing eithersugar or starch Common sugar crops used as feedstocks include sugarcane,sugar beet, and sweet sorghum Feedstocks containing starch or cellulose,which can be converted to sugar, can also be used to produce ethanol Themost common among these include corn, wheat, and cassava Especially inBrazil and other tropical countries, sugarcane is the most widely usedfeedstock In nontropical countries, the starch component of cereals ismore commonly used

Ethanol can be blended with gasoline or burned in its pure form ininternal combustion engines One liter of ethanol contains approximately66% of the energy of 1 l of gasoline, but it has a higher octane level Whenmixed in gasoline, it therefore improves performance and fuel combustion

in vehicles, thereby reducing emissions of carbon monoxide, unburnedhydrocarbons and carcinogens However, the combustion of ethanol alsocauses a heightened reaction with nitrogen in the atmosphere, which canresult in a marginal increase in nitrogen oxide gases Ethanol also onlycontains small amounts of sulfur When mixed with gasoline, ethanoltherefore reduces fuel sulfur content and emissions of sulfur oxide, whichcontributes to acid rain and is a carcinogen

2

One recent article ( Campbell et al., 2009 ) suggests that converting biomass to electricity to power powered vehicles is much more land-use efficient, transport-efficient, and emission-offset efficient than

battery-3.2 Biodiesel

Biodiesel is produced by combining vegetable oil or animal fat with analcohol and a catalyst through transesterification Oil for biodiesel produc-tion can be extracted from most oilseed crops The most popular sources arerapeseed in Europe and soybean in Brazil and the United States In tropicaland subtropical countries, biodiesel is produced from palm, coconut, andjatropha Small amounts of animal fat, from fish- and animal-processingoperations are also used The production process typically yields additionalby-products, such as crushed bean ‘‘cake’’ that can be used as an animalfeed, and glycerine Because biodiesel production can be based on a widerange of oils, the resulting biofuels have a greater range of viscosity andcombustibility than ethanol

Biodiesel can be blended with traditional diesel fuel or burned in pureform in compression ignition engines Its energy content is 88–95% ofregular diesel, but it improves lubricity and raises the cetane value, makingits fuel economy generally comparable to that of diesel Its higher oxygencontent aids in fuel combustion, thereby reducing emissions of particulateair pollutants, carbon monoxide and hydrocarbons Similar to ethanol,biodiesel also contains only traces of sulfur

Straight vegetable oil is another potential fuel for diesel engines that can

be produced from a variety of sources, including oilseed crops, cooking oil,and animal fat

3.3 Cellulosic ethanol

The starch and sugar components of crops represent only a small fraction oftotal plant mass, which is mostly composed of cellulose, hemicellulose, andlignin Cellulose and hemicellulose can be also converted into ethanol afterthey are first converted into sugar, but the process is more difficult A secondgeneration of technology—termed recently the ‘‘holy grail’’ of biofuels(CSM, 2009)—promises to make it economically possible to use cellulosicbiomass for ethanol production There is currently much ongoing researchand even a few pilot plants devoted to converting cellulosic biomass intoethanol, but little commercial-scale production As cellulosic biomass is themost abundant biological material on earth, the successful development ofcommercially viable second-generation cellulose-based biofuels could sig-nificantly expand the volume and variety of feedstocks that can be used forproduction Cellulosic wastes, including waste products from agriculture(straw, stalks, leaves) and forestry, wastes generated from processing (nutshells, sugarcane bagasse, sawdust) and organic parts of municipal waste,could all be potential sources

Potential crops that could serve as a feedstock source for cellulosicethanol include short-rotation woody crops, fast-growing trees, and grassy

species such as switchgrass Since the entire crop can be used, an ideal plantspecies would rapidly produce large amounts of biomass The use of cellu-losic biomass would theoretically permit the production of more fuel perhectare of land Furthermore, some species are adapted to poor degradedsoils, which in theory could provide avenues not only for land rehabilitationbut avoid competition for land with food crops.3

3.4 Biofuel feedstocks and conversion to biofuel

Because nearly any source of biomass can be used for biofuel, there is a widearray of potential biofuel feedstocks across the world Currently, forinstance, by-products of forest industries are used to produce fuelwoodand charcoal, while those of pulp mills provide a major fuel source forbioelectricity generation in many countries A number of crop and forestresidues are also used to produce heat and power

But the largest growth in recent years has been in ethanol and dieselbiofuels for transport using agricultural crops as feedstocks In 2007,85%

of the global production of liquid biofuels was in the form of ethanol(Table 3) Despite the fact that almost any biomass source can be used,most of the world’s ethanol production comes from sugarcane or corn(FAO, 2008) In Brazil, the bulk of ethanol is produced from sugarcane,while in the United States it is produced from corn Other significant

Table 3 2007 ethanol and biodiesel production of the world and selected countries Country/country

feedstocks include cassava, rice, sugar beet, and wheat The two largestethanol producers, Brazil and the United States, made up nearly 90% of totalproduction in 2007, with major production occurring also in Canada,China, the EU (mostly France and Germany), and India.

For biodiesel, the most popular feedstocks are rapeseed in the EuropeanUnion (EU), and soybean in the United States and Brazil Palm, coconut,and castor oils are used in tropical and subtropical countries as biodieselfeedstocks, and the use of jatropha has been rapidly increasing Biodieselproduction was principally concentrated in the EU, with much smallerproduction in the United States Other significant biodiesel producersinclude Brazil, China, India, Indonesia, and Malaysia

Because of potentially rapid changes in prices, government policies,land-use patterns, and public perceptions on food security, subsidies, theenvironment, etc., it is difficult to know how the absolute and relativetrends shown in Table 3 for global biofuel production will evolve amongcountries—changes have been occurring almost weekly (FAO, 2008).Crop yield data inTable 4, taken fromFAO (2008), are presented firstly

to illustrate what agronomists already know very well—crops vary widely interms of yield per hectare across regions and production systems But agrono-mists also know better than any how crop yields change from place to placeand year to year due to a myriad of processes that underlie the complexity ofour science Even the most tranquil agronomist must feel compelled toquestion single static yield values given for, say, corn and soybean for theentire United States Agronomists also know that almost any measure of cropquality, which for biofuels includes sugar, starch, oil, and cellulose contents,also changes with complex environmental and genetic processes

Therefore, without even entering into the chemical engineering aspects

of conversion efficiencies listed in Table 4, agronomists know that theseefficiencies cannot be seen as fixed or static Agronomists, plant breeders,and other agricultural scientists should critically view such static values notonly in terms of how they represent current yields, but how well theyrepresent potential yields that new technologies could bring about This ispart of the centuries-old Malthusian debate (Evans, 1998), which Runge(1990)framed within the context of biofuel and our capacity to sustainablyincrease agronomic production

This is not meant to criticize the illustrative overview given by FAO(2008) It is rather to illustrate just one source of uncertainty and disagree-ment from one of many complex scientific disciplines involved in thebiofuel debate

Further uncertainties come into play when considering all the energyrequirements needed to produce a crop and convert it into biofuel, asillustrated by the range of energy balance calculations shown in Fig 1

A fossil energy balance of 1.0 implies as much energy is needed to produce

1 l of biofuel as it contains An energy balance of 2.0 means that 1 l contains

twice the amount required to produce it The FAO (2008) report usedcalculations from theWorldwatch Institute (2006), an organization whichnot all taking part in the lively debate captured in Table 1 would see asneutral Nonetheless, the figure serves to illustrate that there exist widevariations in energy balances estimated for different feedstocks and fuels.Some of these considerations are mentioned in the contrasting studies of

Pimentel and Patzek (2005) and Liska et al (2008) A simplified list of factors

to consider includes the energy associated with land preparation, growingand harvesting the crop, processing the feedstock into biofuel, transport ofboth feedstock and biofuel, and storage, distribution, and retail of biofuel.For many reasons, including choice of data sources, energy terms that areexcluded or included, and methodologies used, energy balance of biofuel is

a very contentious subject (FAO, 2008)

Table 4 Static estimates of crop yield, conversion efficiencies, and biofuel yields for the world and selected countries

Conversion efficiency

Biofuel yield Sugar

beet

States of America

States of America

From FAO (2008)

Some general conclusions can be drawn nonetheless from the illustrativedata in Tables 3 and 4, andFig 1:

Per area production of biofuel will vary with biomass yield, which differsamong crop species and environments It also changes due to differences

in conversion efficiencies among crops This implies vastly different landrequirements for increased biofuel production, depending on the cropand location

All biofuels appear to make a positive energy contribution, but to widelyvarying degrees (but see thePimentel and Patzek (2005)reference, whichstrongly disagrees)

Estimated fossil fuel balances for biodiesel range from around 1 to 4 forrapeseed and soybean feedstocks Values are much higher for palm oilbecause other oilseeds must be crushed before oil can be extracted (palmoil is often grown in sensitive rainforest environments)

For crop-based ethanol, the estimated balances range from less than 2 forcorn to around 2–8 for sugarcane The favorable fossil energy balance ofsugarcane-based ethanol in Brazil is due to high feedstock productivityand the fact that it is processed using biomass residues from the sugarcane

as an energy input

The range of estimated fossil fuel balances for cellulosic feedstocks is evenwider, reflecting the uncertainty regarding this technology and the diver-sity of potential feedstocks and production systems Overall, the FAO(2008)report finds that most studies project that cellulosic ethanol coulddramatically reduce greenhouse gas emissions compared to petroleumfuels and first-generation biofuels It is harder to convert to liquid fuel,but cheaper to handle and easier to store because it resists deterioration

On the other hand, cellulosic biomass can be bulky and would require adeveloped transportation system, each representing energy requirements

Currently, ethanol production from sugarcane and sugar beet has thehighest energy balance values, with sugarcane-based production in Braziland India near the top of the list.

Yields per hectare for biofuel are somewhat lower for corn, but there aremarked differences between countries for crop yields

None of this takes into account the cost of producing biofuels fromdifferent countries, which among other things would be influenced bygovernment subsidies, transportation infrastructure, and technologicalcapacity

3.5 Bioenergy and biofuel potential on a global scale

It seems appropriate to put the role of biofuels in a global context of energydemand According to theFAO (2008)report:

Bioenergy makes up approximately 10% of total world energy supply.Most consists of traditional, unprocessed biomass such as wood for heating andcooking, but commercial bioenergy is assuming greater importance

Liquid biofuels for transport have received most public attention and haveseen a rapid change increase in production and research spending How-ever, on a global scale their role is only marginal, making up only 1% of totaltransport fuel consumption and 0.2–0.3% of total energy consumptionworldwide

Large-scale production of biofuels will require large areas of land forfeedstock production Among other things, this implies that production

of liquid biofuels could dramatically change current land-use practices,but even so they could only potentially displace fossil fuels for transport to

a very limited extent.4

Even though liquid biofuels supply only a small share of global energyneeds, they still have the potential to have a significant effect on globalagriculture and agricultural markets because of the volume of feedstocksrequired and the relative land areas needed for their production

Second-generation, cellulosic biofuels would increase the quantitativepotential for biofuel generation per hectare of land and could alsoimprove the fossil energy and greenhouse gas balances of biofuels It isnot known when such technologies will enter production on a significantcommercial scale

4 Not all would agree with this At least one study by Sandia National Laboratories and General Motors Corp found that plant and forestry waste and dedicated energy crops could sustainably produce 90 billion gallons of ethanol and replace nearly a third of gasoline use by the year 2030 ( ScienceDaily, 2009a,b,c ) The study assumed 75 billion gallons would be ethanol made from nonfood cellulosic feedstocks and 15 billion gallons

Thus far, we have seen that energy balances, greenhouse gas emissions,and potential for global production of biofuels are controversial and uncer-tain But attendant issues they raise for sustainability are more uncertain andcontentious still.

4 Sustainability Issues

Even 10 years ago, there were more than 100 published definitions ofthe term ‘‘sustainability’’ (Payne et al., 2001) The ASA web site (www.agronomy.org) reminds us that there is actually a legal definition of sustain-able agriculture in the United States (US Code Title 7, Section 3101):

An integrated system of plant and animal production practices having a specific application that will over the long-term:

site-1 Satisfy human food and fiber needs

2 Enhance environmental quality and the natural resource base uponwhich the agriculture economy depends

3 Make the most efficient use of nonrenewable resources and on-farmresources and integrate, where appropriate, natural biological cycles andcontrols

4 Sustain the economic viability of farm operations

5 Enhance the quality of life for farmers and society as a whole

To become sustainable, Payne et al (2001) argued that agriculturalsystems of the world needed to transition toward ones that are characterized

by favorable economics, conservation of resources, preservation of ecology,and promotion of social justice We will consider the current and potentialroles of biofuels in these four categories

US Energy Policy Act of 2005 established the Renewable Fuel Standard

starting at 4 billion gallons in 2006, and rising to 7.5 billion by 2012.This prompted a boom in ethanol plant construction, and the demand forcorn to produce ethanol expanded rapidly Corn prices continued to risesteadily throughout 2006, at least partly due to ethanol demand, while oilprices stayed near $60 per barrel But as corn prices rose, the viability ofcorn as an ethanol feedstock fell,5 even with subsidies, and many ethanolplants began to operate at a loss But when oil prices began to rise sharply inmid-2007 to peak at $145 per barrel in the middle of 2008, corn againbecame economically viable as an ethanol feedstock, at least with subsidies.6And when the price of oil and other commodities fell after mid 2008,ethanol plants again began to go bankrupt across the country (Economist,2009; NYT, 2009a,b).

As touched on in the Runge (1990) paper, the price of corn itself isinfluenced by both agricultural and energy policies A much more thoroughreview of policy effects on biofuel and other commodity prices is included

in theFAO (2008)report, but a major conclusion is that, at least with ourcurrent set of technology, production capacity, and policies on subsidies andimport tariffs, US production of ethanol from corn will be economicallyviable only when oil prices are rising but have not yet driven up corn prices

In a more general sense, because energy markets are large relative toagricultural markets, and because agricultural prices themselves are affected

by energy costs associated with farming, oil prices will drive agriculturalprices To some extent, government policy can modify this relationship.TheFAO (2008)report finds that, in most cases (Brazil’s ethanol productionfrom sugarcane being perhaps an exception), recent policies havebeen costly and have introduced new distortions to already distorted andprotected agricultural markets at both domestic and global levels

Overall, then, economic viability of biofuels is affected by prices ofagricultural feedstocks, technology and infrastructure, and governmentpolicy But the real driving force is the price of oil and other energy sources,which plunged by $115 last year due to falling demand associated with aglobal recession Today demand for oil is still falling at a sustained rate notseen since the early 1980s, and US inventories are higher than sinceSeptember 1990

However, in a recent article, The Economist (2009) reported fears ofSaudi Arabia’s oil minister, the CEO of Chevron, Britain’s energy minister,and others that, when the global economic crisis comes to an end, thedemand for oil will rise and possibly cause another price shock, with prices

5

High prices have also challenged the economic viability of traditionally corn-dependent industries, such as beef, pork, and poultry ( DiLorenzo and Crawford, 2008; Ellis, 2006 ), although by-products such as ‘‘distillers grain’’ can be fed to animals.

possibly surpassing $145 per barrel Many of the factors that drove the pricehike last year remain in place:

Much of the world’s ‘‘easy’’ oil has already been extracted, or is in the hands

of nationalist governments that will not allow foreigners to exploit it That leaves firms to hunt for new reserves in ever more inhospitable and inaccessible places, such as the deep waters off Africa or the frozen oceans

of the Arctic Such fields take a long time and a lot of expensive technology

to develop Worse, new discoveries tend to be smaller than in the past and

to run dry faster.

Additionally, we know that as economies recover, there will be vast newmarkets in the developing world, including China and India, where oilconsumption has been growing fast As soon as the world economy startsgrowing again, demand for oil in theory will once again outstrip thecapacity to supply it, possibly sending prices soaring again This wouldlikely usher in another rush to support and promote ethanol productionfrom crops, which, if the recent trends were repeated, would be economi-cally viable until the prices of feedstocks themselves are driven higher

A very recent NYT (2009b) article sums up the current difficulty inforecasting oil prices, and by inference the economic viability of ethanol andother biofuels: ‘‘The extreme volatility that has gripped oil markets for thelast 18 months has shown no signs of slowing down, with oil prices morethan doubling since the beginning of the year despite an exceptionally weakeconomy The instability of oil and gas prices is puzzling governmentofficials and policy analysts, who fear it could jeopardize a global recovery

It is also hobbling businesses and consumers, who are already facing theeffects of a stinging recession, as they try in vain to guess where prices will be

a year from now—or even next month.’’

4.2 Conservation of resources

The natural resources that may be negatively affected by farming in general,and biofuels in particular, include soil, water, and air Their sustainable use isvital for our very survival All alternative fuel production technologies couldhave environmental impacts; greater understanding is needed to guidepolicy and to avoid or mitigate unintended environmental consequences

of biofuel production (Simpson et al., 2008)

not necessarily cause soil erosion, and that existing research suggested thathigh production and soil conservation were compatible How have wedone since then?

70 million tons of grain and $19 billion for 27 million tons of soybean(ERS/FAS, 2008) The bounty of our farms continues therefore to supportthe profligacy of our energy consumption, but our bounty is not keepingpace with our profligacy—energy consumption has risen much faster thanagricultural productivity

And soil erosion? According to a 2003 report cited byNRCS (2007),erosion rates on a per acre basis declined significantly between 1982 and

2003 The report’s major conclusions include:

Water (sheet and rill) erosion on cropland dropped from 4.0 tons per acreper year in 1982 to 2.6 tons per acre per year in 2003 Wind erosion ratesdropped from 3.3 to 2.1 tons per acre per year

Declines in soil erosion rates have moderated somewhat since 1997, butthe general downward trend in both water and wind erosion continuedthrough 2003

In 2003, 102 million acres (28% of all cropland) were eroding above soilloss tolerance rates, compared to 169 million acres (40% of cropland)

in 1982

In 2003, 266 million acres (72% of cropland) were eroding at or belowsoil loss tolerance rates, compared to 251 million acres (60% of cropland)

in 1982

In 2003, highly erodible land (HEL) cropland acreage was about

100 million acres, compared to 124 million acres in 1982 HEL croplandacreage eroding above soil loss tolerance rates declined 35% between

1982 and 2003

Gains in erosion control continue to occur even though the cropland base

is continually changing Significant acreages of cropland are retired orconverted to other land uses, while new lands not previously cropped arebeing converted to cropland

Thus, at least in the United States, even though above-tolerance rates oferosion continue on a third of our cropland, we have nonetheless seen thatcontinued agricultural intensification has been associated with greater soilconservation, not less

Land-use change and intensification of agricultural production can havesignificant adverse impacts on soils, but all types of erosion have been

researched extensively, and many practices and techniques are available forcontrolling wind and water erosion just about anywhere in the world(Unger et al., 2006a) But some of the regions of the world in which biofuel

is viewed as having the potential to expand—Africa, for example—arecurrently experienced alarming rates of erosion and other forms of landdegradation (Payne, 2010) No one practice or technique—or policy, forthat matter—is universally effective for all climates, soils, landscapes, andmanagement conditions in all seasons or years, but most effective controlsare usually achieved by using some combination of crop residues and soilsurface manipulation

But the very crop residues needed to conserve soil are a potential source

of cellulosic biofuel feedstock, which worries some soil scientists Theamount of residue produced by a given cropping system, and thereforethe amount potentially available as a feedstock while still leaving sufficientamounts for conserving the soil resource, will change with crop species, soilproperties, rainfall, and a long list of agronomic practices In dry areas, there

is often not even sufficient moisture to produce enough residue to achievesoil conservation (Unger et al., 2006a), let alone to export for biofuelproduction Some dryland crops, such as cotton, tend to produce insuffi-cient residue to protect soil from wind erosion (Baumhardt and Salinas-Garcia, 2006), yet cotton residue has been proposed as a source of biofuel

In areas prone to wind erosion, 0.15–0.40 m of standing stubble is mended for small grains (Unger et al., 2006a), which many dryland cropsnever attain Temperature is another consideration, since it strongly influ-ences the rate of residue decomposition (Ladd and Amato, 1985)

recom-Recent research suggests that about 25% of corn stover might besustainably removed from corn cropping systems if they are not on ero-sion-prone lands (Blanco-Canqui and Lal, 2009) Wilhelm et al (2004)

reported that estimates of the amount of corn stover needed to maintainsoil carbon were in the range of 5.25–12.50 Mg ha–1 For wheat-basedsystems,Lafond et al (2009)found that potential exists to use crop residueswithout adversely affecting long-term productivity of medium- to heavy-textured soils, provided that<40% of residue was removed no more than

2 out of 3 years There is surely need for greater research and understanding

in this area

Arguments are presented in theFAO (2008)report that crop feedstocksrequire higher input levels and better-quality land than would second-generation feedstocks such as switchgrass, woody plants or diverse mixtures

of prairie grasses and forbs, or perennial lignocellulosic crops such as lyptus, poplar, or willow These might require less-intensive managementand fewer fossil-energy inputs, and some feedstocks might be grown onpoor-quality land But even for cellulosic feedstocks, there will still be aminimal amount of residue retention needed to conserve soil organic matterand prevent erosion Lee et al (2007) found that switchgrass and other

euca-herbaceous material produced 4–5 Mg ha–1 yr–1, depending on harvestfrequency and N applications, from CRP (Conservation Reserve Program)lands in South Dakota.

The harvest of CRP lands for cellulosic feedstock has been proposed as amethod of offsetting the cost of CRP and subsidizing the cost of biofuels(Walsh et al., 1996) But CRP and other environmentally sensitive, mar-ginal lands serve other purposes, such as wildlife habitat, which may beadversely affected if they become managed principally for biofuel produc-tion We return to this topic under the heading of land-use changes

4.2.2 Water resources

Biofuels have the potential to affect both the availability and the quality ofwater Water resources for agriculture are becoming increasingly scarce inmany countries as a result of increased competition with domestic orindustrial uses (Unger et al., 2006b) Many of the crops currently used forbiofuel production, such as sugarcane, oil palm, and corn, have relativelyhigh water requirements at commercially viable yield levels, and are there-fore best suited to high-rainfall tropical areas, unless they can be irrigated.Rainfed production of biofuel feedstocks is significant in Brazil, where 76%

of sugarcane production is rainfed, and in the United States, where 70% ofcorn production is rainfed (FAO, 2008) Even perennial plants such asjatropha that can be grown in semiarid areas on marginal land may requiresome irrigation during critical growth stages Additionally, processing feed-stocks into biofuels can use large quantities of water, mostly for washingplants and seeds and for evaporative cooling

Many irrigated sugar-producing regions in southern and eastern Africaand northeastern Brazil are already operating near the hydrological limits oftheir associated river basins While the potential for expansion of irrigatedareas may appear high in some areas on the basis of water resources and land,the actual scope can be limited by infrastructure or land tenure systems thatare not easily addressed with commercialized production systems Forexample, there remains an abundant water supply in South Asia and Eastand Southeast Asia, but very little land available for extra irrigated agricul-ture Most potential for expansion is limited to Latin America and Sub-Saharan Africa In Africa in particular, infrastructure is poor, land tenure is athorny issue, and many are very sensitive to the potential of food insecurity(Payne, 2010)

The ‘‘water footprint’’ of bioenergy from crops, that is, the amount ofwater required to cultivate crops for biomass, is much greater than for otherforms of energy A recent Academy of Sciences Report (ScienceDaily,2009b) found that it takes an average of 14,000 l of water to produce 1 l

of biodiesel from rapeseed or soy The research shows that generation ofbioelectricity has a smaller water footprint than the production of biofuels

because the whole plant is used rather than only the sugar, starch, or oil.Cellulosic ethanol would have a much smaller water footprint.

Producing more biofuel crops will affect water quality as well as tity Converting pastures or forests into cropped fields may exacerbateproblems such as soil erosion, sedimentation, and movement of N, P, orpesticides into surface waters or groundwater The same may be true forcellulosic feedstock production if fertilizer and other chemical inputs arerequired to attain commercially viable yields In Brazil, water availability isnot a constraint for sugarcane production, but water pollution associatedwith the application of fertilizers and agrochemicals, soil erosion, sugarcanewashing, and other steps in the ethanol production process are majorconcerns (FAO, 2008)

quan-In the United States, expanded grain-based ethanol is expected toincrease and intensify corn production Even with recommended fertilizerand land conservation measures, corn acreage can be a major source of Nloss to water Simpson et al (2008) estimated that greater corn acreagewould increase N and P loss to water in the United States by 37% (117million kg) and 25% (9 million kg), respectively, and encouraged adoption

of conservation practices to mitigate water quality impairments Theyfurther warned that dried distiller’s grains used as animal feed could increasemanure P content and may increase N content Cellulosic fuel stocks, theyconcluded, had the potential to reduce dependence on grain fuel stocks andprovide improved water quality and other environmental benefits

Biodiesel and ethanol production results in organically contaminatedwastewater that, if released untreated, could increase eutrophication ofsurface waterbodies

In developed countries, existing wastewater treatment technologies candeal effectively with organic pollutants and wastes Whether such facilitieswould be available in developing countries is uncertain On the other hand,because ethanol and biodiesel are biodegradable, the potential for negativeimpacts on soil and water from leakage and spills is reduced compared withthat of fossil fuels (FAO, 2008)

4.2.3 Air resources

For similar reasons of uncertainty and complexity associated with energybalances of biofuels, estimations of the net effect of biofuels on greenhousegas emissions differ widely In the simplest analysis, biofuels would becarbon neutral since their combustion only returns carbon to the atmo-sphere that was fixed by plants—this is why they are perceived by many as asource of renewable energy But the carbon emissions of other processesassociated with the energy balance of biofuels—land preparation, growingthe crop, transportation, marketing, etc.—should also be considered whenestimating greenhouse gas emissions

Depending on the methods used to produce the feedstock and processthe fuel (and, as we have seen, assumptions made in ‘‘life cycle’’ calcula-tions), some crops could actually generate more greenhouse gases than fossilfuels For example, nitrous oxide, a greenhouse gas with a global warmingpotential around 300 times greater than that of carbon dioxide, is releasedfrom nitrogen fertilizers (FAO, 2008) Greenhouse gases are producedduring other activities associated with the production of biofuels as well,including fertilizer, pesticide, and fuel production, industrial processing,transport, and marketing Greenhouse gases can also be emitted fromland-use changes driven by prices and demand associated with increasedbiofuels Not all ‘‘life cycle’’ calculations take into account current orpotential changes in land use.

Given the wide range of biofuels, feedstocks, production and conversiontechnologies, government policies, and existing infrastructure in variouscountries, one should expect a wide range of outcomes in terms of predictedgreenhouse emission reductions from the use of biofuels According to the

FAO (2008), most studies have found that first-generation biofuels fromcurrent common feedstocks reduce emissions 20–60% compared to fossilfuels, provided that the most efficient systems are used and carbon releasesderiving from land-use change are excluded Second-generation biofuels,although still insignificant at the commercial level, might offer emissionreductions in the range of 70–90% compared to fossil fuels excluding carbonreleases related to land-use change When taking into account the effects ofland-use changes,Searchinger et al (2008)estimated that corn-based etha-nol in the United States would actually double greenhouse emissions over

30 years and increase greenhouse gases for 167 years In their calculations,even cellulosic biofuel from switchgrass, if grown on US corn lands, wouldincrease emissions by 50%

4.3 Preservation of ecology

4.3.1 Biodiversity

Biofuel production can directly affect biodiversity following land-usechanges, such as when forests or grasslands are converted into cropland ortree plantations The Convention on Biological Diversity (2008)notes thatmany current biofuels (e.g., sugarcane and oil palm) are well suited to tropicalareas This increases economic incentives to convert natural ecosystemsinto feedstock production systems The extent to which land conversion ishappening in the world is unknown due to lack of data and the almost weeklychange in factors driving biofuel production (FAO, 2008)

Some studies have examined current and potential effects of biodiversityloss due to land-use changes Nelson and Robertson (2008) examinedhow rising commodity prices caused by increased biofuel demand mightinduce land-use change in Brazil, which in turn could endanger bird

species diversity A recent study by the Smithsonian Tropical ResearchInstitute found that conversion of even currently logged forests in Panama

to oil palm plantations could lead to an 80% decline in major animal groups(ScienceDaily, 2009c), but described conservation measures that could miti-gate such devastating effects On the other hand, a recent study in Malaysiafound that very little could be done to make palm oil plantations morehospitable for local birds and butterflies (Koh, 2008) When CRP lands areconverted into crop land, biodiversity associated with native grasses and otherplant species, which provide habitat for several animal species, is at leasttemporarily and locally lost (Roberts et al., 2007; Samson and Knopf, 1996).With respect to cellulosic feedstocks, some of the promoted species areclassified as invasive species, raising new concerns over how to managethem and avoid unintended consequences (FAO, 2008) There are somestudies that suggest that high biodiversity in grasslands, including CRPlands, will lead to exceptionally high levels of biomass production—asmuch as 240% more productive than grasslands with a single prairie species(NSF, 2006)—as well as greater temporal ecosystem stability (Tilman et al.,2006a) However, merely harvesting CRP grasslands in alternate yearsinstead of every year increased the percentage of switchgrass coverage by75% in South Dakota (Lee et al., 2007), underlining the need to understandpotential management effects on biodiversity

Positive effects on biodiversity can be obtained in degraded or marginalareas where new perennial mixed species have been introduced to restoredegraded lands and increase biodiversity (Convention on BiologicalDiversity, 2008) Experimental data from test plots on degraded and aban-doned soils (Tilman et al., 2006b) show that low-input high-diversitymixtures of native grassland perennials, which can also improve wildlifehabitat, water retention, and carbon sequestration, also produce highernet energy gains, greater greenhouse gas emission reductions, and lessagrochemical pollution than do maize-ethanol or soybean-biodiesel.Performance increased with the number of species Tilman et al (2006b)

found that switchgrass can be highly productive on fertile soils, especiallywhen fertilizer and pesticides are applied, but that its performance on poorsoils does not match that of diverse native perennials

In one of the most stridently critical reports on biofuels (Global ForestCoalition, 2007), promotion of cellulosic ethanol feedstocks is seen asleading to the accelerated promotion of fast-growing, easily digested geneti-cally modified trees, which the authors maintain will lead to gene escape andfurther loss of biodiversity through genetic contamination of natural forests.4.3.2 Loss of sensitive lands and land-use change

As already noted, some estimates of energy balances and greenhouse gasemissions do not take into account potential effects of land-use change Data

on land-use change are scant, and future trends are difficult to predict due to

a dynamic economic and policy environment Nonetheless, the potentialimpacts of land-use change must be considered because of possible far-reaching consequences If land-use change involves destruction of forests,wetlands, or grasslands, for example, initial carbon losses may occur which,

if sufficiently large, would require years before emissions savings wouldcompensate

The conclusions ofSearchinger et al (2008)that corn-based ethanol inthe United States would increase greenhouse emissions for 167 years, andswitchgrass-based ethanol would increase emissions by 50%, were alreadymentioned.7 Fargione et al (2008) estimated that converting rainforests,peatlands, savannas, or grasslands to produce food crop-based biofuels inBrazil, Southeast Asia, and the United States creates a ‘‘biofuel carbon debt’’

by releasing 17–420 times more CO2 than the annual greenhouse gas(GHG) reductions that these biofuels would provide by displacing fossilfuels Their calculations suggested that the ‘‘carbon debt’’ of convertingCRP lands to corn-based ethanol would take 48 years to repay; convertingrainforests in the Amazon to produce biodiesel from soybean would take

300 years to repay; and converting tropical peatland rainforests in Indonesia

or Malaysia to produce biodiesel from palm oil would take more than

400 years to repay On the other hand, in their study the production ofbiofuels made from waste biomass or from biomass grown on degraded,marginal lands would incur little or no carbon debt, and could offerimmediate and sustained advantages for greenhouse gas emission

Similarly, Righelato and Spracklen (2007)estimated that more carboncould be sequestered over 30 years from converting cropland to forest thanfrom carbon emission reductions associated with various ethanol and bio-diesel feedstocks They argue that if the objective of biofuel-support policies

is to mitigate global warming (as opposed to achieving energy dence, promoting rural economies, etc.), then greater fuel efficiency andmore forest conservation and restoration programs would be more effective

indepen-It is difficult to assess land-use changes that have occurred so far due todirect and indirect effects of the increase in demand for biofuels.Mitchell’sanalysis (2008) found that the area planted to corn in the United Statesexpanded by 23% in 2007 in response to high prices and demand for cornfor ethanol production This expansion resulted in a 16% decline in soybeanarea, which reduced soybean production and contributed to a 75% increase

in soybean prices between April 2007 and April 2008 In the EU, theexpansion of biodiesel production diverted land from wheat, which affectedworld wheat supply In response to the increased demand and rising pricesfor oilseeds, land area planted to oilseeds in several countries increased,

7

A response to the Searchinger et al (2008) article, including challenges to its assumptions and methodologies, can be found in a report by Darlington (2009) The report is linked at the National Corn Growers

especially for rapeseed and, to a lesser extent, sunflower The increase wasprimarily in the countries that are also major wheat exporters, includingArgentina, Canada, Europe, Russia, and Ukraine The eight largest wheatexporting countries expanded area in rapeseed and sunflower by 36%, or 8.4million ha, between 2001 and 2007 Area planted to wheat decreased byabout 1% The wheat production potential of this land was 26 million tons,based on average wheat yields in each country, with a cumulative wheatproduction potential of 92 million tons from 2002 to 2007 In the fall of

2007, when about 2 million ha of CRP land came up for contract renewal,only half were reentered into the program, including about a third of amillion ha of grasslands devoted to the so-called duck factory in the UpperMidwest The remainder was put back into production (NYT, 2008b;USDA, 2007) One report (Hettenaus, 2006) claimed that the DOE andUSDA anticipated that as many as 60 million acres of cropland, croplandpasture, and conservation acreage would be converted to perennial cropproduction once the technology for converting cellulosic biomass to etha-nol is demonstrated at a commercial scale

Data on land-use change in developing countries are more difficult totrack, but change is surely occurring.Bekunda et al (2009)describe large-and small-scale biofuel programs in Brazil, India, China, and many Sub-Saharan African countries, driven by a desire for reduced reliance on costlyand unstable imported energy supplies and the need to spur rural develop-ment They found it likely that many of these biofuel programs and projectsare being launched without considering and enacting long-term policies InIndia, projected land-use change includes 10.4 Mha for production ofjatropha to meet projected biodiesel needs, mostly in marginal

‘‘wastelands.’’

Because of rapid change in economic forecasts, public perception, andgovernments’ policies, it is more difficult still to predict future effects ofbiofuels on land-use change The FAO (2008) report states that, of theworld’s 13.5 billion ha of total land surface area, about 8.3 billion arecurrently in grassland or forest and 1.6 billion ha in cropland An additional

2 billion hectares are considered potentially suitable for rainfed crop duction, but much of this land provides valuable environmental services,including carbon sequestration, water filtration, and protection of biodiver-sity After excluding forest land, protected areas, and land needed to meetincreased demand for food, crops, and livestock,FAO (2008), citingFischer(2008), estimates the amount of land potentially available for expanded cropproduction to be 250–800 million ha, most of which is in tropical LatinAmerica and Africa Some of this land could be used directly for biofuelfeedstock production

pro-TheFAO (2008)projects that land used for the production of biofuelswill expand three- to fourfold at the global level, depending on policiespursued, over the next few decades, and even more rapidly in Europe and

North America, including a global shift toward cereals over the next decade.Associated land-use changes would affect noncereal croplands in Australia,Canada, and the United States, set-aside lands in the EU, CRP lands in theUnited States, and new, currently uncultivated land, especially in LatinAmerica Oil palm production, for example, may drive increased land-usechange in rainforests of the Amazon, Africa, and Asia (ScienceDaily, 2009c).Formerly marginal, unprofitable land may also return to production, includ-ing as much as 23 million ha in Kazakhstan, Russia, and Ukraine Sugarcanearea in Brazil is expected to almost double to 10 million ha over the nextdecade, along with further expansion of soybean area China is also enroll-ing large amounts of land in a ‘‘Grain-for-Green’’ program Again, theseland-use changes are speculative, and will depend upon several externalfactors, notably prices, availability of fuel and food, and government policy.Land-use change could result from indirect effects of biofuel production,such as the increase in soybean production observed in Brazil in response todecreased production in the United States TheFAO (2008)study suggeststhat Brazilian land prices may double as a result of increased demand forgrains, oilseeds, and sugarcane, and that European and US biofuel mandateswould cause decreased exports from those countries, thereby placing morepressure on ecosystems in other parts of the world.

4.4.1 Biofuel and food security

The most contentious issue within the category of social justice is the effect

of biofuel and associated policies on food security in general, and foodprices in particular.8 Many have concluded that ethanol and biodiesel

8

While I have devoted much of my career to issues of food security in developing countries, I have also received generous research support from what some might see as ‘‘proethanol’’ organizations, such as the National Grain Sorghum Producers ( http://www.sorghumgrowers.com ), the Texas Corn Producers Board

biofuels—and the policies that promote them—bear much of the bility for high food prices and widespread hunger among the poor in theworld during 2008 Some of the other contributing and politically contestedfactors to blame are accelerating Asian demand for food and energy, highenergy prices, increasing meat consumption, adverse weather conditionsincluding persistent drought in Australia, commodities speculation, a weakdollar, foreign accumulation of dollars as exchange reserves, and several policyresponses of various governments, such as elimination of export subsidies,increased taxes on exports, and limits or even bans on exports of grain andgrain products (Bertini and Glickman, 2009; Payne, 2009; Trostle, 2008).High food prices and low supply in 2008 compromised food security inmany poor countries of the world Food insecurity can cause politicalinstability (Bertini and Glickman, 2009; Payne, 2010), as evidenced byriots over rising food prices in 30 countries, and sweeping last-minutemeasures by governments to support domestic agriculture, such as thepromotion of rice production in many West African states who had beenaccustomed to importing cheap rice from Asia In Africa, riots were espe-cially bad in Somalia, Egypt, Burkina Faso, Cote d’Ivoire, Ethiopia, Niger,Morocco, Mozambique, and Senegal The worst reported incident was inCameroon, where several were killed and more than 1500 arrested (Payne,

responsi-2010) Other countries that experienced social unrest due to food insecurityinclude Mexico, Philippines, Bangladesh, Yemen, Thailand, and Uzbekistan(Trostle, 2008) If one accepts that food security is an aspect of social justice,then it is hard to argue that social justice was ill served throughout the worldduring the food crisis of 2008 In Africa, food prices still remain dispropor-tionally high following the 2008 spikes relative to pre-crisis prices (Payne,

2010) Did biofuel production and policies contribute to this social injustice?

Mitchell (2008)cites (but does not entirely agree with) studies suggestingthat contribution of biofuel production to increased food prices were ashigh as 70% during the last few years In one of the more critical articles onbiofuel policy and food prices, Runge and Senauer (2007) cite IFPRIestimates that, with continued high oil prices, the drive to accelerate globalbiofuel production would lead to increases in corn prices of 20% by 2010and 41% by 2020 The prices of oilseeds, including soybeans, rapeseed, andsunflower, were projected to rise by 26% by 2010 and 76% by 2020,and wheat prices by 11% by 2010 and 30% by 2020 In the poorest parts

of Sub-Saharan Africa, Asia, and Latin America, cassava prices wereexpected to increase by 33% by 2010 and 135% by 2020.9

At the other extreme, in May 2008, Edward Lazear, the former Bushadministration’s chairman of the White House Council of Economic

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The report also states that price increases might be mitigated if crop yields increase substantially or cellulosic ethanol production becomes commercially viable, but notes that, unless biofuel policies change significantly,