Vinod Kosla On Better agronomy for energy crops  

Grist has the second installment of Vinod Khosla's series on biomass energy - this one looking at ways to produce biomass for cellulosic ethanol sustainably, in-line with his CLAW requirements. This episode has a lot in common with one of the chapters in Janine Benyus' book "Biomimicry"

I believe improved crop practices are a vital aspect in meeting our cellulosic feedstock needs. There are a few areas that offer significant potential:

1. crop rotation,
2. the use of polyculture plantations,
3. perennials as energy crops, and
4. better agronomic practices.

We address all four issues here. Though none of these have been extensively studied, early studies and knowledgeable speculation point to their likely utility. Further study of these techniques is urgently needed, especially the use of grasses or other biomass-optimized winter cover crops.

Crop rotation

I have proposed the usage of a 10 year x 10 year energy and row crop rotation. As row crops are grown in the usual corn/soy rotation, lands lose topsoil and get degraded, need increased fertilizer and water inputs, and decline in biodiversity. By growing no-till, deep-rooted perennial energy crops (like miscanthus or switchgrass -- see below) for ten years following a ten year row crop cycle, the carbon content of the soil and its biodiversity can be improved and the needs for inputs decreased. The land can then be returned to row crop cultivation after ten years of no-till energy crops.

Currently unusable degraded lands may even be reclaimed for agriculture using these techniques over a few decades. A University of North Dakota study highlights some of the benefits for food crops. I expect similar or even greater benefits for food crop/energy crop long cycle rotations, especially in soil carbon content:

* Improved yields: a crop grown in rotation with other crops will show significantly higher yields than a crop grown continuously.
* Disease control: changing environmental conditions (by changing crops) changes the effect of various diseases that may set in with an individual crop, and crop rotation can limit (and often eliminate) diseases that affect a specific crop.
* Soil nitrogen: legumes (or other nitrogen-fixing crops) used as part of a rotation help to restore the nitrogen that has been depleted by previous crop harvests allow a field to remain fertile for longer periods. Energy crops in the rotation can increase soil carbon content and reduce the impact of topsoil loss materially.
* Better land: the study notes that farmers practicing crop rotations comment on improvements in soil stability and friability. In addition, crop rotations have the potential to increase the efficiency of water usage (by rotation deep-rooted and more moderately rooted crops, or rotation of perennials in long cycles with row crops).

One aspect of the crop-rotation approach is utilizing cover crops such as grasses, legumes, or small grains that are grown between regular crop production periods (i.e., winter for most crops, and summer for winter-specific crops such as winter wheat). As Part I details, Professor David Bransby has noted that such crops require no additional irrigation, and use about 30 percent of the fertilizer of regular crops like corn. Elsewhere, Professor Greg Roth at Penn State is studying the usage of specific winter cover crops (like hulless barley) and has noted it could be used to increase biofuel yields per acre. ...

In addition to providing biomass, winter cover crops provide the benefits of crop rotation -- adding organic matter to the soil, recycling nutrients, and more efficient usage of soil and water resources. Further study of these winter cover crops as a potential biomass source is needed, but they could provide a significant portion of our biofuel land needs while improving the land's ecology over just planting row crops and leaving the land unused during the winter. This will also improve row crop agriculture during the summer. It is even possible that winter cover crops could eliminate the need for most additional lands to meet our biofuels needs in the U.S.

Use of polyculture plantations

Another important crop practice is the idea of utilizing polyculture species instead of monocultures. This is particularly possible for energy crops, as many processes can accept a mixture of biomass types. The Land Institute notes that polycultures (and the resulting plant diversity) have significant benefits, from the provision of an "internal supply of nitrogen, management of exotic and other harmful organisms, soil biodiversity, and overall resilience of the system." Further research shows that grasslands that suffer from overgrazing or drought tend to recover faster if there is greater biodiversity.

The Australian Rural Industries Research and Development Corporation notes (PDF) that "polyculture is shown to offer the proverbial 'free lunch' by producing more from less." The report goes on to note that polycultures yield in greater amounts from smaller areas, and their yields are generally more stable than monocultures (with regards to income level and general risk). Furthermore, polycultures were found to be more efficient in gathering resources such as light, water, and soil nutrients. Elsewhere, Professor David Tilman at the University of Minnesota has highlighted the yield and environmental benefits of polyculture crops. These benefits are starting to gain recognition -- Ceres Corporation has proposed an alternative approach they call polycultivation. ...

Part 3 of Vinod's series looks at what he considers the most important factor - biomass yields.

My most critical assumption with cellulosic biofuels is on land efficiency: tons of biomass per acre, and hence gallons of fuel produced per acre, and more accurately, miles driven per acre. I believe biomass yields per acre will multiply by two to four times from today's norms.

The lack of genetic optimization and research on cultural practices, harvesting, storage, and transport with would-be energy crops -- miscanthus, sorghum, switchgrass, and others -- means that there is significant potential for improvement. The application of advanced breeding methods like genetic engineering and marker-assisted breeding, limiting water usage through drought resistant crops, and large-scale application of biotechnology (i.e., optimizing the process by which plants conduct photosynthesis, or reducing stress-based yield losses) will also contribute to increased yields with fewer inputs.

More importantly, different energy crops are likely to be optimal for different climates -- jatropha makes sense on degraded Indian land, but not in the American Midwest. Rather than a single dominant energy crop, we are likely to see a variety of feedstocks that allow specialization to local conditions, mixes, and needs, while mitigating the risks.

Some reported examples and datapoints of biomass yields speak to the reasonableness of our estimates of yields between 18-24 tons per acre by 2030 (e.g., Prof. Lee Lynd at Dartmouth):

* Miscanthus averaged 16.5 dry tons per acre per year, where switchgrass averaged 4.6 at 3 Illinois sites, with data taken over 3 years. Research in Europe notes yields ranging up to 16 dry tons per acre (PDF).
* Sugarcane ventures in Brazil (Allelyx is using GMO techniques, Canavalis is using more traditional plant breeding) are breeding energy cane that will likely result in a yield of 25 dry tons per acre/year of harvestable biomass. Similar progress is being made by USDA sugarcane geneticists in Louisiana.
* Megaflora Corp. has measured productivities of 28 dry tons per acre per year from crossing North American hardwoods with the paulownia tree in North Carolina. Similar progress is being made by USDA sugarcane geneticists in Louisiana.
* Anagenesis Corp claims of their trees, "one acre can yield 48x times as much ethanol as an acre of corn."
* DOE estimates (PDF) suggest that collecting existing biomass with only a small change in agricultural practices could generate 1.3 billion dry tons of biomass in the U.S. (most of our biomass needs) and still be able to meet all food, feed, and export demands. This would be an alternative scenario to get biomass without energy crops.
* According to Prof. Mark Holtzapple at Texas A&M, high-yield sorghum can be grown in 35 U.S. states and produce yields as high as 25 dry tons per acre/year with low water usage.
* Researchers at Texas A&M have developed new "freakishly tall sorghum plants" that reach heights of nearly 20 feet -- more than double the height of regular sorghum and yielding double the amount of crop per acre. They use little water and have been bred to prevent flowering (thus trapping more energy), and can be grown on marginal crop lands.

A wide variety of crops have potential as feedstocks for cellulosic ethanol. Bical notes: "The criteria for the ideal energy crop are high dry matter yield, perennial growth, and efficient use of nitrogen, water, other resources, and pest and disease resistance." The previously cited Univ. of Illinois study compared corn, short-rotation coppice, and miscanthus versus a set of idealized criteria for energy crops and found miscanthus (and by extension, other C4 photosynthetic grasses) to meet most of the requirements (PDF, or see charts below). Of particular interest to me is miscanthus that "partitions nutrients back to the roots in the fall just before harvesting." I figure crops that provided (and survived) energy for mammals in the prairies can now provide energy for humans!

Many of the advantages of miscanthus are also applicable to some of the other proposed feedstocks. The new, higher-yielding strains of sorghum developed at Texas A&M use less water than conventional sorghum (making them more drought-resistant) and are sterile (not flowering prevents the escape of energy). Their 20-feet height means that yields have effectively doubled. ...

While its great to see someone like Vinod posting at Grist and providing some detailed reasoning about why he chooses to invest in biofuels, I'm still far from convinced that this is the way to go, believing that converting to a clean energy / electric transport system is a much better (and less risky) way to go. But I suspect we will see a fair amount of biofuel (or biomass fueled power generation) in use in the future - and I'm glad Vinod isn't just investing in lots of corn ethanol facilities and trying to defend that option as a valid one.

On the subject of corn ethanol, the Christian Science Monitor has an article wondering if global food price rises can be blamed on the biofuel boom.

The biofuels industry plans on producing record amounts of ethanol this year to meet a mandate of the new US energy law – and will need a lot of corn to do it. At the same time, global food prices are at near-peak levels. The question is, how big is the connection between those two developments?

It's a topic getting more scrutiny as the world enters 2008 with the lowest grain stockpiles on record, near-record grain prices, and prospects for even tighter supplies as global demand rises for food and fuel.

Political instability over higher food prices is a key concern. Last year saw tortilla demonstrations in Mexico, pasta protests in Italy, and unrest in Pakistan over bread prices. Soybean prices, meanwhile, prompted demonstrations in front of Indonesia's presidential palace. Food inflation in China is a major problem.

But the connection between the expansion of biofuels and higher global food prices is not clear cut, with the biofuels industry saying its impact is relatively small and biofuel critics saying that ethanol plants are driving up the price of corn and biodiesel producers are taking a bite out of the soybean crop.

"The United States, in a misguided effort to reduce its oil insecurity by converting grain into fuel for cars, is generating global food insecurity on a scale never seen before," says Lester Brown, president of the Earth Policy Institute (EPI), an environmental think tank in Washington. World population growth will require food for an additional 70 million people this year, the EPI said in a report last week.

Driven mostly by population growth, world grain consumption rose an average of 21 million tons per year from 1990 to 2005, the US Department of Agriculture reported this month. Demand for grain to make ethanol soared by 27 million tons last year, USDA reported.

"Putting [corn-ethanol] land back into food use would have a profound effect on the price of corn," says Bruce Babcock, an economist at Iowa State University's Food and Agricultural Policy Research Institute. This year, he estimates, the US will produce about 8 billion gallons of ethanol. To do that, nearly one-fifth of the 80 million acres now devoted to corn will go to make ethanol.

That demand is helping to boost feed prices for cattle, as well as for crops like peas and beans because less land is devoted to growing them, he says.

In a counterpoint study last month by corn growers and the biofuels industry, higher corn prices were found to be only a small element in rising food costs overall – although higher energy costs for fuel to transport crops and grow them were a larger factor.

"This analysis puts to bed the argument that a growing domestic ethanol industry is solely responsible for rising consumer food prices," Bruce Scherr, CEO of Informa Economics, a food and agriculture research and consulting firm based in Memphis, Tenn., said in a statement.

The "farm value" of commodity raw materials used in foods accounts for 19 percent of total US food costs, down from 37 percent in the 1973. Higher costs for labor, packaging, transportation, and energy were a "key driver" behind higher food costs, the report said.

While higher corn prices cause lower profit margins for livestock and poultry producers, "the statistical evidence does not support a conclusion that there is a strict 'food-versus-fuel' trade-off" driving consumer food prices higher, the study said.

Whatever the reason, prices for grains such as corn and soybeans are up. Despite a record US corn crop in fall 2007, corn prices are near a record high of about $5 a bushel in mid-January.

Because corn is feedstock, higher corn prices can affect food prices. The average price of milk rose 29 percent last year, for instance, and eggs 36 percent.

"More people are coming to the conclusion that there is a food-fuel link," says Siwa Msangi of the International Food Policy Research Institute (IFPRI), a Washington food-security research organization. "The historic pattern of the past, where food prices were in a long-term decline, could be at an end."

But the major reason grain prices are spiking, he and others note, is fast-rising demand for higher-quality food like meat, poultry, and dairy products by the increasingly affluent people of China and India.

Still, biofuels play a role in higher grain prices, says Dr. Babcock.

His findings are bolstered by a study last month in which Mr. Msangi's IFPRI estimated that future biofuel expansion could increase international corn prices between 26 and 72 percent by 2020, depending on how aggressive the expansion turns out to be.

Under two scenarios IFPRI examined, "the increase in crop prices resulting from expanded biofuel production was accompanied by a net decrease in the availability of ... food" for the world's poor, the study found.

As prices rise, of course, producers worldwide have incentive to grow more corn – or other crops, such as wheat, that might be in demand instead of corn.

But that's not happening yet. In an apparent effort to moderate food prices and quell social unrest – which in turn curbs growers' incentive to produce more – Russia this month is expected to place a 40 percent export tax on wheat. Argentina, too, has limited its wheat exports.