Biology Comics

Why Ethanol Is Brown

In 2010, 119 million metric tonnes of the U.S. corn crop (out of 400 million metric tonnes; between one third and one fourth of the total) went to make ethanol. This sent corn prices near record highs.

U.S. corn production has been rising at 2% a year for 30 years, mostly from plant breeding. (The limits of using more and more fertilizer were reached earlier). The crop went from 4 billion bushels in 1970 to 10 billion bushels in 2000.

In 2008 the U.S. corn crop was 12.8 billion bushels. About 40% went to feed animals, 30% for ethanol, 8% was processed for starch, corn oil and sweeteners, 15% was exported (mostly for animal feed). The sweeteners include high fructose corn syrup, a mixture of glucose and fructose which is used to sweeten sodas and processed foods. Fructose is the sugar found in honey and fruits. Unlike glucose (our main source of sugar) it doesn’t promote the release of insulin from pancreatic cells (the cells lack receptors for fructose) and thus doesn’t lead to the biochemical cascade that results in the secretion of leptin, the hormone that tells us we are full (stop eating!). Ingesting lots of fructose (as in soft drinks) leads to weight gain and the associated insulin resistance (which may be a direct result of too much fructose) and Type II diabetes. High fructose corn syrup is cheap and so products sweetened with it are cheap, but full of calories: a disaster—cheap unhealthy foods. We live in a world where buying a candy bar makes more sense than buying an apple.


Michael Pollan describes the miasmic smell of a cattle feedlot hanging over the Kansas plains. The cattle, fattened on a food (corn) to which they are not adapted, are maintained on low dose antibiotics, and develop life threatening strains of e coli in their intestines (life threatening to us, not to the cattle): the bugs disappear when the cattle are fed hay.

The corn is grown as a monoculture (nothing but corn in sight), fed with manufactured nitrogen fertilizer synthesized from natural gas, protected from competition with weeds by herbicides and from insects by pesticides. Resistance to the most popular herbicide, along with some insect killing toxins, are built into the genetically altered corn plants, whose seed is obtained from the manufacturer of the herbicide (a nifty deal for the seed-producing manufacturer).

Because of the petrochemicals (fertilizer, diesel fuel, pesticide) used to grow corn, and because of the energy required to distill it, ethanol is energy neutral or energy negative: that is, more energy goes into making ethanol than it contains. (Not very green.)

On a regenerative farm, rotating row crops with hays improves the tilth of soils, stores carbon, provides most of the nutrients for the following crops. The hay is sold or used to feed cattle.

Industrial corn is not rotated with hays. It is often rotated with soybeans (another animal feed). Both corn and soybeans are row crops whose fields shed topsoil into streams. Soybeans fix nitrogen from nitrogen gas in the atmosphere (making it usable to plants) but only enough for their own use. The manure the feedlot cattle produce is not used to fertilize the corn that feeds them (the corn is grown 100-1000 miles away). Some manure is processed into animal feed, some is spread (far too heavily) on nearby fields.

The extra nutrients from the feedlots and from the fields of corn and soybeans, along with topsoil (a bushel of topsoil for a bushel of corn), herbicides and pesticides, are carried by rain into rivers and streams; some seep down into groundwater, or volatilize into the air. (Herbicides from middle western farms are detectable in spring rains in the northeastern United States.)

Excess nutrients in streams cause algae to grow and reproduce. The algae are always there (they are a basis of the streams’ food chain) but their growth is limited by nutrients and by predation from small animals (zooplankton), which are eaten (as are the algae) by fish.

The flood of nutrients from corn and soybean fields, along with their topsoil, overwhelms the natural systems of streams. Water clouded with algae and silt shades out rooted underwater plants that hold and oxygenate bottom sediments and serve as nurseries for fish. The fish populations change from sight feeders (game fish like bass and pike) to bottom feeders like European carp that locate prey by touch and smell; or to fish that filter algae from the water column (two species of Asian carp that escaped from catfish farms in the Mississippi drainage). Overfertilized lakes and rivers stink, as the algae dies and sinks to the bottom. Most rivers in American farm country (reported by early travellers as clear) are murky with algae and silt. The silt settles out behind dams, shortening their lives.

The nutrients, pesticides and herbicides are carried by rivers to the sea. “Dead zones” off the coasts of developed countries are common. Decaying algae deprive the water of oxygen; few fish or invertebrates can survive. Herbicides injure water plants and riverside trees. As estuaries like Chesapeake Bay are overwhelmed by nitrogen and their sea grass meadows die, they lose their value as nurseries for marine fish; oysters disappear; they become dominated by algae and jellyfish (a predator of algae).

Much of this can be traced to poor farming practices: soybeans, corn, ethanol.

Ethanol production (like corn production) is subsidized. Its use in motor fuels is mandated. That it takes more energy to produce than it contains is ignored (a technical problem). This is a wonderful story for corn farmers (who have seen the price of corn near record levels), for the agribusinesses that distill ethanol, for the government whose support payments are no longer necessary. Perhaps less wonderful for drivers, who see their mileage fall while the price of motor fuel remains the same, and may have damage to their vehicles through improperly mixed fuels.

The agricultural support system that began under Franklin Roosevelt (the ever-normal granary; a very old concept of ensuring a food supply) limited the acreage of crops that could be grown on a farm. In return, the government would buy up the surplus at a reasonable price and resell it on the market when demand allowed. Thus the supply of grain would be maintained at a price that profited farmers; and enough grain would be available to feed the population.

Rising food prices under President Nixon forced a change in this policy: farmers were encouraged to grow as much as they could. The government would support the price at the cost of production. So farmers expanded their plantings. (Some conservation limits have been imposed recently.) Ethanol offered a way out of low corn prices caused by the continually expanding corn crop.

Suppose, instead of ethanol, or corn, biologically appropriate farming were subsidized. Farmers would be encouraged to grow an amount of grain their landscape could absorb; that would keep topsoil and nutrients on their fields and out of streams. Their fields would be part of a biologically working landscape, with herbivores (rabbits and deer), predators (foxes and coyotes), songbirds, hawks, amphibians, insects.

From 15% to 40% of such farms would be natural landscape—forest, desert, prairie. These landscapes store carbon (worth, say, $25-$50 an acre) and harbor insects, bats and birds and small predators that help the farmer. (When the farmers of Kern County, California, managed to exterminate their coyotes, the resulting overpopulation of mice chewed their way through their crops.) This natural land might be beside streams. If not, a band of hayfield or lightly grazed pasture 100-300 feet wide should border streams.

Where possible (providing water is a problem), cattle are grazed several months of the year on rotational pastures—small plots grazed for three days or a week, then rested for a month or six weeks. (The pastures are sometimes grazed after the cattle by chickens, which eat the hatching fly larvae out of the manure, spreading the manure in the process.) Grassland birds, the most endangered in the United States today, and ducks, breed in rotational pastures (the cattle graze around their nests). Modern hayfields are cut too often for successful nesting. Game birds and animals are part of farms with natural habitat and spilled grain. Canada Geese are attracted to the Chesapeake region by the spilled corn (about 10% of the crop) left in the fields. Prairie chickens probably increased in numbers as the prairie was settled, and more food was available in farmers’ fields, then disappeared as the larger landscape was reduced to grain fields and they lost their breeding grounds. Quail nest in damp thickets in Carolina corn and soybean fields. So hunting rights can be leased; and farms become attractive places to visit.

Row crops on the regenerative farm are rotated with hays. A third of the cultivated ground is in hays at any one time. (The corn crop is now down by a half to a third and the price of corn is as high as now.) Cattle are brought back to the farm to eat the hays, their manure used to grow the farm’s crops.

Cattle are grazed on small rotating pastures in summer and fall, fed baled hay in winter. Pigs are raised in large hoop houses bedded with hay, free to root, socialize, build great communal nests in the hay. After they are slaughtered, the hay and manure is scraped up and spread on the fields; or the house moved and the ground used to grow vegetables.

The corn stalks and cobs from fields harvested for grain are chopped and partially burned in a kiln to provide heat for the farmer’s house (hot tub, greenhouse) and biochar, a fine charcoal. Biochar increases the productivity of soils (some claim by several times) by storing and releasing nutrients (thus reducing losses through leaching). It locks up the carbon in the corn stalks for tens of thousands of years.

With the right management regenerative farms can grow food, improve soils, provide habitat for wild animals and store carbon.

The streams that run through the farm are clear and swimmable; the ocean estuaries and marine fisheries (with limits on fishing and fishing gear and large protected areas) recovering.

Green dreams! What corporation will profit? And population continues to grow, the demand for meat and grain with it…