Peak Soil: Why Cellulosic ethanol and other Biofuels are Not Sustainable and a Threat to America's National Security - Part I


5.7.07   Alice Friedemann, Freelance Journalist
“The nation that destroys its soil destroys itself,” President Franklin D. Roosevelt.

Part 1. The Dirt on Dirt

Ethanol is an agribusiness get-rich-quick scheme that will bankrupt our topsoil.

Nineteenth century western farmers converted their corn into whiskey to make a profit (Rorabaugh 1979). Archer Daniels Midland, a large grain processor, came up with the same scheme in the 20th century. But ethanol was a product in search of a market, so ADM spent three decades relentlessly lobbying for ethanol to be used in gasoline. Today ADM makes record profits from ethanol sales and government subsidies (Barrionuevo 2006).

The Department of Energy hopes to have biomass supply 5% of the nation’s power, 20% of transportation fuels, and 25% of chemicals by 2030. These combined goals are 30% of the current petroleum consumption (DOE Biomass Plan, DOE Feedstock Roadmap).

Fuels made from biomass are a lot like the nuclear powered airplanes the Air Force tried to build from 1946 to 1961, for billions of dollars. They never got off the ground. The idea was interesting – atomic jets could fly for months without refueling. But the lead shielding to protect the crew and several months of food and water was too heavy for the plane to take off. The weight problem, the ease of shooting this behemoth down, and the consequences of a crash landing were so obvious, it’s amazing the project was ever funded, let alone kept going for 15 years.

Biomass fuels have equally obvious and predictable reasons for failure. Odum says that time explains why renewable energy provides such low energy yields compared to non-renewable fossil fuels. The more work left to nature, the higher the energy yield, but the longer the time required. Although coal and oil took millions of years to form into dense, concentrated solar power, all we had to do was extract and transport them (Odum 1996)

With every step required to transform a fuel into energy, there is less and less energy yield. For example, to make ethanol from corn grain, which is how all ethanol is made now, corn is first grown to develop hybrid seeds, which next season are planted, harvested, delivered, stored, and preprocessed to remove dirt. Dry-mill ethanol is milled, liquefied, heated, saccharified, fermented, evaporated, centrifuged, distilled, scrubbed, dried, stored, and transported to customers (McAloon 2000).

Fertile soil will be destroyed if crops and other “wastes” are removed to make cellulosic ethanol.

“We stand, in most places on earth, only six inches from desolation, for that is the thickness of the topsoil layer upon which the entire life of the planet depends” (Sampson 1981).

Loss of topsoil has been a major factor in the fall of civilizations (Sundquist 2005 Chapter 3, Lowdermilk 1953, Perlin 1991, Ponting 1993). You end up with a country like Iraq, formerly Mesopotamia, where 75% of the farmland is a salty desert.

Fuels from biomass are not sustainable, are ecologically destructive, have a net energy loss, and there isn’t enough biomass in America to make significant amounts of energy because essential inputs like water, land, fossil fuels, and phosphate ores are limited.

Soil Science 101 – There Is No “Waste” Biomass

Long before there was “Peak Oil”, there was “Peak Soil”. Iowa has some of the best topsoil in the world. In the past century, half of it’s been lost, from an average of 18 to 10 inches deep (Pate 2004, Klee 1991).

Productivity drops off sharply when topsoil reaches 6 inches or less, the average crop root zone depth (Sundquist 2005).

Crop productivity continually declines as topsoil is lost and residues are removed. (Al-Kaisi May 2001, Ball 2005, Blanco-Canqui 2006, BOA 1986, Calviño 2003, Franzleubbers 2006, Grandy 2006, Johnson 2004, Johnson 2005, Miranowski 1984, Power 1998, Sadras 2001, Troeh 2005, Wilhelm 2004).

On over half of America’s best crop land, the erosion rate is 27 times the natural rate, 11,000 pounds per acre (NCRS 2006). The natural, geological erosion rate is about 400 pounds of soil per acre per year (Troeh 2005). Some is due to farmers not being paid enough to conserve their land, but most is due to investors who farm for profit. Erosion control cuts into profits.

Erosion is happening ten to twenty times faster than the rate topsoil can be formed by natural processes (Pimentel 2006). That might make the average person concerned. But not the USDA -- they’ve defined erosion as the average soil loss that could occur without causing a decline in long-term productivity.

Troeh (2005) believes that the tolerable soil loss (T) value is set too high, because it's based only on the upper layers -- how long it takes subsoil to be converted into topsoil. T ought to be based on deeper layers – the time for subsoil to develop from parent material or parent material from rock. If he’s right, erosion is even worse than NCRS figures.

Erosion removes the most fertile parts of the soil (USDA-ARS). When you feed the soil with fertilizer, you’re not feeding plants; you’re feeding the biota in the soil. Underground creatures and fungi break down fallen leaves and twigs into microscopic bits that plants can eat, and create tunnels air and water can infiltrate. In nature there are no elves feeding (fertilizing) the wild lands. When plants die, they’re recycled into basic elements and become a part of new plants. It’s a closed cycle. There is no bio-waste.

Soil creatures and fungi act as an immune system for plants against diseases, weeds, and insects – when this living community is harmed by agricultural chemicals and fertilizers, even more chemicals are needed in an increasing vicious cycle (Wolfe 2001).

There’s so much life in the soil, there can be 10 “biomass horses” underground for every horse grazing on an acre of pasture (Wardle 2004). If you dove into the soil and swam around, you’d be surrounded by miles of thin strands of mycorrhizal fungi that help plant roots absorb more nutrients and water, plus millions of creatures, most of them unknown. There’d be thousands of species in just a handful of earth –- springtails, bacteria, and worms digging airy subways. As you swam along, plant roots would tower above you like trees as you wove through underground skyscrapers.

Plants and creatures underground need to drink, eat, and breathe just like we do. An ideal soil is half rock, and a quarter each water and air. When tractors plant and harvest, they crush the life out of the soil, as underground apartments collapse 9/11 style. The tracks left by tractors in the soil are the erosion route for half of the soil that washes or blows away (Wilhelm 2004).

Corn Biofuel (i.e. butanol, ethanol, biodiesel) is especially harmful because:

  • Row crops like corn and soy cause 50 times more soil erosion than sod crops (Sullivan 2004) or more (Al-Kaisi 2000), because the soil between the rows can wash or blow away. If corn is planted with last years corn stalks left on the ground (no-till), erosion is less of a problem, but only about 20% of corn is grown no-till. Soy is usually grown no-till, but insignificant residues to harvest for fuel.


  • Corn uses more water, insecticide, and fertilizer than most crops (Pimentel 2003). Due to high corn prices, continuous corn (corn crop after corn crop) is increasing, rather than rotation of nitrogen fixing (fertilizer) and erosion control sod crops with corn.


  • The government has studied the effect of growing continuous corn, and found it increases eutrophication by 189%, global warming by 71%, and acidification by 6% (Powers 2005).


  • Farmers want to plant corn on highly-erodible, water protecting, or wildlife sustaining Conservation Reserve Program land. Farmers are paid not to grow crops on this land. But with high corn prices, farmers are now asking the Agricultural Department to release them from these contracts so they can plant corn on these low-producing, environmentally sensitive lands (Tomson 2007).


  • Crop residues are essential for soil nutrition, water retention, and soil carbon. Making cellulosic ethanol from corn residues -- the parts of the plant we don’t eat (stalk, roots, and leaves) – removes water, carbon, and nutrients (Nelson, 2002, McAloon 2000, Sheehan, 2003).

These practices lead to lower crop production and ultimately deserts. Growing plants for fuel will accelerate the already unacceptable levels of topsoil erosion, soil carbon and nutrient depletion, soil compaction, water retention, water depletion, water pollution, air pollution, eutrophication, destruction of fisheries, siltation of dams and waterways, salination, loss of biodiversity, and damage to human health (Tegtmeier 2004).

Why are soil scientists absent from the biofuels debate?

I asked 35 soil scientists why topsoil wasn’t part of the biofuels debate. These are just a few of the responses from the ten who replied to my off-the-record poll (no one wanted me to quote them, mostly due to fear of losing their jobs):

  • “I have no idea why soil scientists aren't questioning corn and cellulosic ethanol plans. Quite frankly I’m not sure that our society has had any sort of reasonable debate about this with all the facts laid out. When you see that even if all of the corn was converted to ethanol and that would not provide more than 20% of our current liquid fuel use, it certainly makes me wonder, even before considering the conversion efficiency, soil loss, water contamination, food price problems, etc.”


  • Biomass production is not sustainable. Only businessmen and women in the refinery business believe it is.


  • "Should we be using our best crop land to grow gasohol and contribute further to global warming? What will our children grow their food on?"


  • “As agricultural scientists, we are programmed to make farmer's profitable, and therefore profits are at the top of the list, and not soil, family, or environmental sustainability”.


  • “Government policy since WWII has been to encourage overproduction to keep food prices down (people with full bellies don't revolt or object too much). It's hard to make a living farming commodities when the selling price is always at or below the break even point. Farmers have had to get bigger and bigger to make ends meet since the margins keep getting thinner and thinner. We have sacrificed our family farms in the name of cheap food. When farmers stand to make few bucks (as with biofuels) agricultural scientists tend to look the other way”.


  • You are quite correct in your concern that soil science should be factored into decisions about biofuel production. Unfortunately, we soil scientists have missed the boat on the importance of soil management to the sustainability of biomass production, and the long-term impact for soil productivity.

This is not a new debate. Here’s what scientists had to say decades ago:

Removing “crop residues…would rob organic matter that is vital to the maintenance of soil fertility and tilth, leading to disastrous soil erosion levels. Not considered is the importance of plant residues as a primary source of energy for soil microbial activity. The most prudent course, clearly, is to continue to recycle most crop residues back into the soil, where they are vital in keeping organic matter levels high enough to make the soil more open to air and water, more resistant to soil erosion, and more productive” (Sampson 1981).

“…Massive alcohol production from our farms is an immoral use of our soils since it rapidly promotes their wasting away. We must save these soils for an oil-less future” (Jackson 1980).

Natural Gas in Agriculture

When you take out more nutrients and organic matter from the soil than you put back in, you are “mining” the topsoil. The organic matter is especially important, since that’s what prevents erosion, improves soil structure, health, water retention, and gives the next crop its nutrition. Modern agriculture only addresses the nutritional component by adding fossil-fuel based fertilizers, and because the soil is unhealthy from a lack of organic matter, copes with insects and disease with oil-based pesticides.

“Fertilizer energy” is 28% of the energy used in agriculture (Heller, 2000). Fertilizer uses natural gas both as a feedstock and the source of energy to create the high temperatures and pressures necessary to coax inert nitrogen out of the air (nitrogen is often the limiting factor in crop production). This is known as the Haber-Bosch process, and it’s a big part of the green revolution that made it possible for the world’s population to grow from half a billion to 6.5 billion today (Smil 2000, Fisher 2001).

Our national security is at risk as we become dependent on unstable foreign states to provide us with increasingly expensive fertilizer. Between 1995 and 2005 we increased our fertilizer imports by more than 148% for Anhydrous Ammonia, 93% for Urea (solid), and 349 % of other nitrogen fertilizers (USDA ERS). Removing crop residues will require large amounts of imported fertilizer from potential cartels, potentially so expensive farmers won’t sell crops and residues for biofuels.

Improve national security and topsoil by returning residues to the land as fertilizer. We are vulnerable to high-priced fertilizer imports or “food for oil”, which would greatly increase the cost of food for Americans.

Agriculture competes with homes and industry for fast depleting North American natural gas. Natural gas price increases have already caused over 280,000 job losses (Gerard 2006). Natural gas is also used for heating and cooking in over half our homes, generates 15% of electricity, and is a feedstock for thousands of products.

Return crop residues to the soil to provide organic fertilizer, don’t increase the need for natural gas fertilizers by removing crop residues to make cellulosic biofuels.

Part 2. The Poop on Ethanol: Energy Returned on Energy Invested (EROEI)

To understand the concept of EROEI, imagine a magician doing a variation on the rabbit-out-of-a-hat trick. He strides onstage with a rabbit, puts it into a top hat, and then spends the next five minutes pulling 100 more rabbits out. That is a pretty good return on investment!

Oil was like that in the beginning: one barrel of oil energy was required to get 100 more out, an Energy Returned on Energy Invested of 100:1.

When the biofuel magician tries to do the same trick decades later, he puts the rabbit into the hat, and pulls out only one pooping rabbit. The excrement is known as byproduct or coproduct in the ethanol industry.

Studies that show a positive energy gain for ethanol would have a negative return if the byproduct were left out (Farrell 2006). Here’s where byproduct comes from: if you made ethanol from corn in your back yard, you’d dump a bushel of corn, two gallons of water, and yeast into your contraption. Out would come 18 pounds of ethanol, 18 pounds of CO2, and 18 pounds of byproduct – the leftover corn solids.

Patzek and Pimentel believe you shouldn’t include the energy contained in the byproduct, because you need to return it to the soil to improve nutrition and soil structure (Patzek June 2006). Giampetro believes the byproduct should be treated as a “serious waste disposal problem and … an energy cost”, because if we supplied 10% of our energy from biomass, we’d generate 37 times more livestock feed than is used (Giampetro 1997).

It’s even worse than he realized – Giampetro didn’t know most of this “livestock feed” can’t be fed to livestock because it’s too energy and monetarily expensive to deliver – especially heavy wet distillers byproduct, which is short-lived, succumbing to mold and fungi after 4 to 10 days. Also, byproduct is a subset of what animals eat. Cattle are fed byproduct in 20% of their diet at most. Iowa’s a big hog state, but commercial swine operations feed pigs a maximum of 5 to 10% byproduct (Trenkle 2006; Shurson 2003).

Worst of all, the EROEI of ethanol is 1.2:1 or 1.2 units of energy out for every unit of energy in, a gain of “.2”. The “1” in “1.2” represents the liquid ethanol. What is the “.2” then? It’s the rabbit feces – the byproduct. So you have no ethanol for your car, because the liquid “1” needs to be used to make more ethanol. That leaves you with just the “.2” --- a bucket of byproduct to feed your horse – you do have a horse, don’t you? If horses are like cattle, then you can only use your byproduct for one-fifth of his diet, so you’ll need four supplemental buckets of hay from your back yard to feed him. No doubt the byproduct could be used to make other things, but that would take energy.

Byproduct could be burned, but it takes a significant amount of energy to dry it out, and requires additional handling and equipment. More money can be made selling it wet to the cattle industry, which is hurting from the high price of corn. Byproduct should be put back into the ground to improve soil nutrition and structure for future generations, not sold for short-term profit and fed to cattle who aren’t biologically adapted to eating corn.

The boundaries of what is included in EROEI calculations are kept as narrow as possible to reach positive results.

Researchers who find a positive EROEI for ethanol have not accounted for all of the energy inputs. For example, Shapouri admits the "energy used in the production of … farm machinery and equipment…, and cement, steel, and stainless steel used in the construction of ethanol plants, are not included". (Shapouri 2002). Or they assign overstated values of ethanol yield from corn (Patzek Dec 2006). Many, many, other inputs are left out.

Patzek and Pimentel have compelling evidence showing that about 30 percent more fossil energy is required to produce a gallon of ethanol than you get from it. Their papers are published in peer-reviewed journals where their data and methods are public, unlike many of the positive net energy results.

Infrastructure. Current EROEI figures don’t take into account the delivery infrastructure that needs to be built. There are 850 million combustion engines in the world today. Just to replace half the 245 million cars and light trucks in the United States with E85 vehicles will take 12-15 years, It would take over $544 million dollars of delivery ethanol infrastructure (Reynolds 2002 case B1) and $5 to $34 billion to revamp 170,000 gas stations nationwide (Heinson 2007).

The EROEI of oil when we built most of the infrastructure in this country was about 100:1, and it’s about 25:1 worldwide now. Even if you believe ethanol has a positive EROEI, you’d probably need at least an EROEI of at least 5 to maintain modern civilization (Hall 2003). A civilization based on ethanol’s “.2” rabbit poop would only work for coprophagous rabbits.

Of the four articles that showed a positive net energy for ethanol in Farrells 2006 Science article, three were not peer-reviewed. The only positive peer-reviewed article (Dias De Oliveira, 2005) states “The use of ethanol as a substitute for gasoline proved to be neither a sustainable nor an environmentally friendly option” and the “environmental impacts outweigh its benefits”. Dias De Oliveria concluded there’d be a tremendous loss of biodiversity, and if all vehicles ran on E85 and their numbers grew by 4% per year, by 2048, the entire country, except for cities, would be covered with corn.

Part 3. Biofuel is a Grim Reaper

The energy to remediate environmental damage is left out of EROEI calculations.

Global Warming

Soils contain twice the amount of carbon found in the atmosphere, and three times more carbon than is stored in all the Earth’s vegetation (Jones 2006).

Climate change could increase soil loss by 33% to 274%, depending on the region (O'Neal 2005).

Intensive agriculture has already removed 20 to 50% of the original soil carbon, and some areas have lost 70%. To maintain soil C levels, no crop residues at all could be harvested under many tillage systems or on highly erodible lands, and none to a small percent on no-till, depending on crop production levels (Johnson 2006).

Deforestation of temperate hardwood forests, and conversion of range and wetlands to grow energy and food crops increases global warming. An average of 2.6 million acres of cropland were paved over or developed every year between 1982 and 2002 in the USA (NCRS 2004). The only new cropland is forest, range, or wetland.

Rainforest destruction is increasing global warming. Energy farming is playing a huge role in deforestation, reducing biodiversity, water and water quality, and increasing soil erosion. Fires to clear land for palm oil plantations are destroying one of the last great remaining rainforests in Borneo, spewing so much carbon that Indonesia is third behind the United States and China in releasing greenhouse gases. Orangutans, rhinos, tigers and thousands of other species may be driven extinct (Monbiot 2005). Borneo palm oil plantation lands have grown 2,500% since 1984 (Barta 2006). Soybeans cause even more erosion than corn and suffer from all the same sustainability issues. The Amazon is being destroyed by farmers growing soybeans for food (National Geographic Jan 2007) and fuel (Olmstead 2006).

Biofuel from coal-burning biomass factories increases global warming (Farrell 2006). Driving a mile on ethanol from a coal-using biorefinery releases more CO2 than a mile on gasoline (Ward 2007). Coal in ethanol production is seen as a way to displace petroleum (Farrell 2006, Yacobucci 2006) and it’s already happening (Clayton 2006).

Current and future quantities of biofuels are too minuscule to affect global warming (ScienceDaily 2007).

Surface Albedo. “How much the sun warms our climate depends on how much sunlight the land reflects (cooling us), versus how much it absorbs (heating us). A plausible 2% increase in the absorbed sunlight on a switch grass plantation could negate the climatic cooling benefit of the ethanol produced on it. We need to figure out now, not later, the full range of climatic consequences of growing cellulose crops” (Harte 2007).


Farm runoff of nitrogen fertilizers has contributed to the hypoxia (low oxygen) of rivers and lakes across the country and the dead zone in the Gulf of Mexico. Yet the cost of the lost shrimp and fisheries and increased cost of water treatment are not subtracted from the EROEI of ethanol.

Soil Erosion

Corn and soybeans have higher than average erosion rates. Eroded soil pollutes air, fills up reservoirs, and shortens the time dams can store water and generate electricity. Yet the energy of the hydropower lost to siltation, energy to remediate flood damage, energy to dredge dams, agricultural drainage ditches, harbors, and navigation channels, aren’t considered in EROEI calculations.

The majority of the best soil in the nation is rented and has the highest erosion rates. More than half the best farmland in the United States is rented: 65% in Iowa, 74% in Minnesota, 84% in Illinois, and 86% in Indiana. Owners seeking short-term profits have far less incentive than farmers who work their land to preserve soil and water. As you can see in the map below, the dark areas, which represent the highest erosion rates, are the same areas with the highest percentage of rented farmland. Gallery/sediment.htm

Water Pollution

Soil erosion is a serious source of water pollution, since it causes runoff of sediments, nutrients, salts, eutrophication, and chemicals that have had no chance to decompose into streams. This increases water treatment costs, increases health costs, kills fish with insecticides that work their way up the food chain (Troeh 2005).

Ethanol plants pollute water. They generate 13 liters of wastewater for every liter of ethanol produced (Pimentel March 2005)

Water depletion

Biofuel factories use a huge amount of water – four gallons for every gallon of ethanol produced. Despite 30 inches of rain per year in Iowa, there may not be enough water for corn ethanol factories as well as people and industry. Drought years will make matters worse (Cruse 2006).

Fifty percent of Americans rely on groundwater (Glennon 2002), and in many states, this groundwater is being depleted by agriculture faster than it is being recharged. This is already threatening current food supplies (Giampetro 1997). In some western irrigated corn acreage, groundwater is being mined at a rate 25% faster than the natural recharge of its aquifer (Pimentel 2003).


Every acre of forest and wetland converted to cropland decreases soil biota, insect, bird, reptile, and mammal biodiversity.

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