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Study Suggests That Use of Land-Efficient Animal Feed Technologies and Double Cropping Could Reconcile Large-Scale Biofuel Production With Food Production

8 October 2010

Annual mass flows from the current allocation of 114 million ha (left) versus a land efficient allocation (right) showing all major crops and outputs for the maximum ethanol production scenario. CO2 listed is biogenic carbon released during fermentation. Credit: ACS, Dale et al. Click to enlarge.

Large scale biofuel production can be successfully reconciled with food production through the use of land-efficient animal feed technologies and double-cropping while also accomplishing significant greenhouse gas reductions and promoting biodiversity, according to a new analysis by Dr. Bruce Dale and colleagues at Michigan State University.

Their analysis, published as an open access paper in the ACS journal Environmental Science & Technology, found that while using less that 30% of total US cropland, pasture and range, up to 400 billion liters (106 billion gallons US) of ethanol can be produced annually without decreasing domestic food production or agricultural exports. Their approach reduces US greenhouse gas emissions by up to 670 Tg CO2-equivalent per year—more than 10% of total US annual emissions—while increasing soil fertility and promoting biodiversity. It also eliminates the indirect land use change (ILUC) effect.

Our analysis shows that the US can produce very large amounts of biofuels, maintain domestic food supplies, continue our contribution to international food supplies, increase soil fertility, and significantly reduce GHGs. If so, then integrating biofuel production with animal feed production may also be a pathway available to many other countries. Resolving the apparent “food versus fuel” conflict seems to be more a matter of making the right choices rather than hard resource and technical constraints. If we so choose, we can quite readily adapt our agricultural system to produce food, animal feed, and sustainable biofuels.

—Dale et al.

More than 80% of total agricultural production in the United States is used to feed animals, not human beings directly; most animal feed is produced for cattle, which are “nutritionally versatile animals”, Dale et al. note. In their study, they analyzed only the 114 million ha of cropland used now to produce animal feed, corn ethanol, and exports. Cropland used for direct human consumption, forests, grassland pasture, and rangeland are not considered. Thus, they note, the analysis provides an example of what is technically feasible, not an upper limit on US biofuel production.

For the study, they considered two land-efficient animal feed technologies: ammonia fiber expansion (AFEX) pretreatment to produce highly digestible (by ruminants) cellulosic biomass and leaf protein concentrate (LPC) production.

  • During AFEX, concentrated ammonia is contacted with cellulosic biomass at moderate temperatures, resulting in greatly increased production of fermentable sugars by enzymatic hydrolysis. AFEX increases the digestibility of cellulosic biomass for ruminant animals while increasing protein production in the animal rumen due to the addition of ammonia-based byproducts.

    Although extensive feed testing and commercial applications have not yet been introduced, AFEX-treated rice straw has been successfully included in dairy cattle diets, and tests with switchgrass and corn stover have shown increased cell wall digestibility when exposed to rumen microorganisms.

  • High-protein LPC products are generally produced by first pulping and then mechanically pressing fresh green plant matter. The resulting protein-rich juice is then coagulated and dried. The remaining fibrous material is depleted in protein, but is still suitable for animal feed or biofuel production.

Animal feeding operations can be adapted to these new feeds, thereby freeing land for biofuel production, according to the authors. They also considered aggressive double-cropping, thereby increasing the total biomass produced per ha.

The researchers built a nonlinear optimization model to determine either the maximum ethanol production or maximum GHG reduction available from the 114 million ha of land. Either ethanol production or GHG reduction was maximized by varying the amount of land dedicated to each type of crop as well as how each crop is used subject to constraints regarding animal feeding, export requirements, and biodiversity. The model is limited in that it does not consider spatial parameters (such as variance in yields), temporal parameters (such as increasing population or crop yields), nor does it consider other policy or behavioral shifts such as changing human diets away from red meat consumption.

We believe our analysis is conservative in that it under predicts potential GHG reductions and biofuel production. For example, our analysis does not deal with (i) changing dietary trends which might reduce the need for animal feeds, (ii) more efficient use of grassland pasture and range, (iii) utilization of cellulosic residues other than corn stover, (iv) higher CBC yields, (v) more use of double crops beyond the one-third limit imposed in our analysis, or (vi) any biomass derived from forests. Each of these factors would likely increase biofuel production and further reduce GHG emissions while also reducing pressure on agricultural land. Except for possible increases in nitrate emissions, environmental services such as enhanced biodiversity, increased soil organic matter, and reduced GHG emissions are well served by the approaches outlined here.

...As noted, the technologies that provide most of the benefit to food and biofuel production are extensive double cropping and large scale production of diverse cellulosic crops appropriate to different regions of the country. These are not exotic, expensive, or high risk technologies. Considering their large benefits to energy security and climate security, extensive double cropping and production of diverse cellulosic crops deserve more study for widespread application in integrated biofuel and animal feeding systems than they have received to date.

—Dale et al.


  • Bruce E. Dale, Bryan D. Bals, Seungdo Kim, and Pragnya Eranki (2010) Biofuels Done Right: Land Efficient Animal Feeds Enable Large Environmental and Energy Benefits. Environ. Sci. Technol., Article ASAP doi: 10.1021/es101864b

October 8, 2010 in Ethanol, Sustainability | Permalink | Comments (23) | TrackBack (0)


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USA, Brazil, Russia, Australia, Canada, Argentina, with relative low population per hectare, could afford to divert some crop lands to liquid fuel production.

However, the majority is not in the same favorable position. Countries like China, India, and many others, with very large population to feed, do not have the luxury to use a high percentage of their farm lands to produce liquid fuel.

We often make the mistake of thinking that what is good for us is also good for the rest of the world.

World population may reach 10 to 12 B much sooner than we think and most of the good farm lands will be required to feed it. Instead of using good productive farm lands to produce liquid fuel we could use various wastes and simultaneously reduce liquid fuel usage with electrification of most ground vehicles and machines.

Let us no be taken for a ride by organized farm lobbies.

"We believe our analysis is conservative in that it under predicts potential GHG reductions and biofuel production.``

Of course this is a model and we have learned these can be deeply flawed and politicized. But this looks like a reasonable plan for biofuel production in the future. It will be immediately refuted by oil industry people threatened by a sustainable resource.

Not mentioned is the prospect for algal-based biofuels that also yield animal feed protein. This avenue should be thoroughly explored in pursuit of any biofuel policy.

What about soil health? We're facing too much erosion and compaction without diverting so much residues or dedicating crop for energy and fuel production.

Find out more information on Biomass Energy
or download our Biomass Fact Sheet.

Also see our relevant page on Biofuels.

I really see only Big Oil group which I would like avoid when making my mind. This study really shows what was obvious in the beginning. Ethanol is not the one to blame for food price or starvation. Meet consumption is also not the reason for high food price. The shift to biomass ethanol will not change picture on the world food market because when producing ethanol your are not consuming food. It is obvious without any study. And argument that you consuming food for ethanol is fake.

The same Big Oil argument is that EV and EREVS do not effect or EVEN increase CO2 emission. That it is difficult to oppose because it is obvious that it is nonsense. It is obvious that is only real path of reducing CO2 emissions, because electricity used for transportation is and always will be even 100% vehicles electrified small fraction of electricity consumption. In US it would be no more than 6%. Therefore you should concentrate on CO2 reduction within power generation and electrical propulsion will become C02 free automatically. This is no any other realistic way to fight greenhouse (if it is real) than those ways. But more important issue is US economy sustainability.

USA's economy sustainability is a major issue. Our numerous acquired addictions make most possible solutions a challenge. We will resist to most required changes.

We don't like hybrids or electrified fuel saving vehicles. We don't want to pay a few more cents for non-junk foods. Our children do not want to do away with their 100+ cheaply made in China toys and games. We all want overly large homes even if we can no longer pay for them. The list could be a mile long.

To balance our trade and reduce our unemployment we want other nations to increase the value of their money while in reality our US $$ should be (and is actually being) progressively devalued by up to 50% instead. The truth is that our standard of living will go down either way. A progressive devaluation of the US$$ may be coming and has in fact been going on for the last few years. Will it reach the same value as the Euro? May be it should and will by 2012-2015.

If they can get cellulose front ends for existing ethanol plants, they can transition from corn grain to corn stalks and cobs. What is left over can be gasified to make methanol or more ethanol.

As one of the few farmers who has actually grown switchgrass as a commercial crop, I've thought for a long time we need to be looking at ways to access cellulosic biomass directly.

A field in perennial grass, like switchgrass, has very little soil erosion. In fact, quite the opposite happens. These perennial grasses build soil and sequester carbon by translocating nutrients into their below ground biomass, which far exceeds what is seen above ground.

Instead of depending on annual plants, as we have done for the last 10,000 years, to act as miniature chemical factories synthesizing and concentrating nutrients in their seed heads or tubers, so that we can access those nutrients for ourselves and our animals, the better path would be to extract nutrients directly from the vegetative parts of plants, preferably from perennials. This is exactly what this research has accomplished.

Let's not stop at processing leaf and stalk matter for animal feed. Let's find a way to do the same to create human feed. Then we'll be on the way to a huge paradigm shift in agriculture and get us away from soil disturbance and high fertility regimes that annual plant agriculture requires.

A good point Fred. However, if there is a dollar to be made, farmers will use good farm land to produce whichever non-food plants they can make more money with. Viewed from a farmer point of view, growing switchgrass and other perennial grass to produce liquid fuel will reduce the availability of normal (edible) farm products, farmers will get a better (higher) price and make more profit etc.

In other words, farmers like all business people, don't really care if there is enough food to go around but care about higher produce price and higher profits. At $5+/gallon, all corn, sugar canes and other similar edible farm products would be turned into ethanol. Half of us may go hungry put farmers would do much better if the ethanol factories give them the right price for their products. Historically, this has not always been the case.

"Their approach reduces US greenhouse gas emissions ...more than 10% of total US annual emissions—while increasing soil fertility and promoting biodiversity"

...oh, and will also give every child in America a magical pony!

Common sense suggests that if this system really is the most profitable way to produce food it would already be the way we produce food.

And oil companies love biofuel. Should it ever prove profitable they will twitch their little finger and buy up every ethanol refinery in existence. It perpetuates their business model of producing liquid fuels for internal combustion engines where 80 percent of the energy in a tank is wasted.

Actually 1% of the energy in gasoline is used to get the driver down the road. Most goes out as heat and to move the car itself.

Apparently these are people who think land (as in sq miles) is the only resource needed. They don't consider water, phosphates etc which are all constrained.

Moreover, we can't just keep on taking stuff out of soil. Until artificial fertilizers were made using petroleum, soil was replunished using what came out of it. These guys think you can just burn all that stuff off or feed to animals. What happens to the soil as we run out of petroleum and fertilizers made out of it ?

Oh, my bad. 99% is wasted ; )

I guess the driver could walk and save 100%. This just shows how inefficient a car is. You have to move the car and driver but 70-80% going out as heat is bad. Like I say, the car gets zero miles per gallon at a stop light without a start/stop system.

Harvey D,
Article demonstrates that in reality ethanol is NOT produced from food or instead of food. The corn used for ethanol production normaly is dryed and used as animal feed. One could argue that lot of natural gas is used during drying process, but that is another issue. That is why celulosing ethanol could be more profitable because no need of drying of waste.

Harvey D has a point. Non-subsistence farmers do not grow food in order to feed the world; farmers produce food and fiber as cash crops to generate an income to support their own families. In a capitalist system with private property rights they have the ability to choose for themselves what they want to grow.

If farm production generates more net income as biofuel than as feed, then it would be the logical from the farmer's point of view to take that option. How many non-farmers would prefer a lower income option in their own lives?

The main point I want to emphasize, however, is the need for a paradigm shift in agriculture: away from the pattern of the last 10,000 years in depending on annual plants and switching to perennial vegetative matter to produce feed, human and animal. This would reduce fertilizer and chemical requirements, reduce soil disturbance and resultant soil erosion, reduce on-farm capital investments and debt loads, while at the same time increasing production to meet the needs of an expanding human population.

This Michigan State research has the significance of Norman Borlaug's Green Revolution. Borlaug is the single human being who has had the greatest effect on the daily lives of the greatest number of people in history. That's pretty significant.

"These guys think you can just burn all that stuff off or feed to animals. What happens to the soil as we run out of petroleum and fertilizers made out of it ?"

Er, how about the age old practice of using animal waste as fertilizer? Most farmers know the value of manure.

@Fred: Not sure this study will affect the millions who benefited from Borlaug's genetic engineering. Fungus resistant crops produce food in abundance - this study shows how food and energy crops can co-exist.

OT: Odd that Borlaug is an atheist hero - where other scientists of his caliber are not.

It would be amazing to develop a perennial corn crop. Just cut if off at the ground, use the grain for feed/food, the stalks and cobs for fuel and it just grows back. Combine that with under ground drip irrigate with nutrients in the water and save water and fertilizer.

Good on Fred,
As a horticulturalist, some of the modern deconstructed can see that it is possible to both remediate and make productive - just as the thoughtless can destroy the best nature can offer.
The trick is IMO to set the bar at a achieving both targets. At least then no one should argue the destructive outcome.

The downside then would be the diversion of productive intellectual and logistical phisical resources from food production.
That is another question and there may be a range of legitimate 'ethical' views on that.

Nature herself is also a major contributer and resource that can assist us if we respect and understand her needs.

I thnk that the point Fred makes that degrading of any land is not prerequisite is valid.
Of course, this depends on best practice and everything depends on educated persons getting involved at all levels of society.

The 'other' ethical consideration must include consideration of fertility and reproductive rights . giving women the right to choose (however unpopular this subject may be in the various religious and patriarchal societies) is the sensible approach to reducing overpopulation and the excessive demands it places on natural systems.

The fact is that we live in a constrained world and most people refuse to accept that fact.
Given that, wars and starvation will be the alternative option that can allow biodiversity and humans to continue.

Producing animal feed is much the same as producing human food. After an inefficient process (about 9% for beef), we eat the animal that we fed with grain etc.

Since producing chickens is about 4 times as efficient as producing beef, we should produce beef tasting chickens for human food and feed 4 times more people with the same input. Beef producing industries (and the Beef Party) would never allow it.

Perennial corn is probably not impossible to do but specialized high profit seed growers (and the Corn Party) would never allow it.

Do you mean that we have to cater to the politically possible? Then it followers that me must update our obsolete constitution!

I suggest:

1.One term in any elective office.
2.Politicians may only share their limited time with constituants.
3.Do away with the electorial college.
4.Offering or accepting anything other that a limited government paid salery shall be treated as treason, punishable by death.

"follows that WE"

Elected politicians do longer govern; lobbies, speculators, financial supporters and pressure groups do.

Your no. 4) may be essential to liberate our political leaders and give them a free hand to govern. How would you stop the brown envelops and the old boys clubs?

"The fact is that we live in a constrained world and most people refuse to accept that fact."

Actually, most people DO accept that idea which empowers the thought. Should they think and act antithetically - there would be a different approach to distribution of wealth and resources. Unfortunately, the human race remains largely fearful of "not enough." This attitude drives the fear that drives the hoarding and conflict.

When the people finally see the universe is abundant and limitless - and consider themselves as a part of that universe - the fear will abate.

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