The quickest way to relieve pressure on world food prices would be to cut U.S. subsidies for ethanol and drop import tariffs on Brazilian ethanol. But there are longer-term steps we need to take as well if we are to ensure food for everyone. The other reason grain prices have spiked is that oil prices have spiked, and industrial agriculture has become heavily reliant on fossil fuel–for fertilizer, for pesticide, for processing and transportation. Today it takes 10 calories of fossil-fuel energy to produce one calorie of food energy. We need to reduce the dependence of modern agriculture on oil, an eminently feasible goal–after all, agriculture is the original solar “technology,” and sustainable farmers have shown us how we might put our food system back on a foundation of sunlight. For example, when you take cattle off their typical feedlot diet of grain and allow them to eat grass, those hamburgers put less pressure on the prices of both oil and grain.

That brings me to the third, and perhaps least tractable, factor behind the run-up in world grain prices: the growing appetite for meat in places like China and India. Most of the world’s grain goes to feed animals, not people, and meat is a very inefficient use for that grain–it takes 10 pounds of grain to make one pound of beef. There would be plenty of grain for everyone if we actually ate it as food and didn’t use it to make meat. Reducing world meat consumption–or feeding our food animals differently–would leave more grain for the world’s hungry.

It comes down to this: the world’s agricultural lands make up a precious and finite resource; we should be using it to grow food for people, not for cars or cattle.

For an American like me, growing up linked to a very different food chain, yet one that is also rooted in corn, not to think of himself as a corn person suggests either a failure of imagination or a triumph of capitalism.

Or perhaps a little of both. For the great edifice of variety and choice that is an American supermarket rests on a remarkably narrow biological foundation: corn. It’s not merely the feed that the steers and the chickens and the pigs and the turkeys ate; it’s not just the source of the flour and the oil and the leavenings, the glycerides and coloring in the processed foods; it’s not just sweetening the soft drinks or lending a shine to the magazine cover over by the checkout. The supermarket itself–the wallboard and joint compound, the linoleum and fiberglass and adhesives out of which the building itself has been built–is in no small measure a manifestation of corn.

There are some 45,000 items in the average American supermarket, and more than a quarter of them contain corn. At the same time, the food industry has done a good job of persuading us that the 45,000 different items or SKUs (stock keeping units) represent genuine variety rather than the clever rearrangements of molecules extracted from the same plant.

How this peculiar grass, native to Central America and unknown to the Old World before 1492, came to colonize so much of our land and bodies is one of the plant world’s greatest success stories. I say the plant world’s success story because it is no longer clear that corn’s triumph is such a boon to the rest of the world.

At its most basic, the story of life on earth is the competition among species to capture and store as much energy as possible–either directly from the sun, in the case of plants, or, in the case of animals, by eating plants and plant eaters. The energy is stored in the form of carbon molecules and measured in calories: the calories we eat, whether in an ear of corn or a steak, represent packets of energy once captured by a plant. Few plants can manufacture quite as much organic matter (and calories) from the same quantities of sunlight and water and basic elements as corn.

The great turning point in the modern history of corn, which in turn marks a key turning point in the industrialization of our food, can be dated with some precision to the day in 1947 when the huge munitions plant at Muscle Shoals, Alabama, switched over from making explosives to making chemical fertilizer. After World War II, the government had found itself with a tremendous surplus of ammonium nitrate, the principal ingredient in the making of explosives. Ammonium nitrate also happens to be an excellent source of nitrogen for plants. Serious thought was given to spraying America’s forests with the surplus chemical, to help the timber industry. But agronomists in the Department of Agriculture had a better idea: spread the ammonium nitrate on farmland as fertilizer. The chemical fertilizer industry (along with that of pesticides, which are based on the poison gases developed for war) is the product of the government’s effort to convert its war machine to peacetime purposes. As the Indian farmer activist Vandana Shiva says in her speeches, “We’re still eating the leftovers of World War II.”

F1 hybrid corn is the greediest of plants, consuming more fertilizer than any other crop. Though F1 hybrids were introduced in the 1930s, it wasn’t until they made the acquaintance of chemical fertilizers in the 1950s that corn yields exploded. The discovery of synthetic nitrogen changed everything–not just for the corn plant and the farm, not just for the food system, but also for the way life on earth is conducted.

All life depends on nitrogen; it is the building block from which nature assembles amino acids, proteins and nucleic acid; the genetic information that orders and perpetuates life is written in nitrogen ink. But the supply of usable nitrogen on earth is limited. Although earth’s atmosphere is about 80 percent nitrogen, all those atoms are tightly paired, nonreactive and therefore useless; the 19th-century chemist Justus von Liebig spoke of atmospheric nitrogen’s “indifference to all other substances.” To be of any value to plants and animals, these self-involved nitrogen atoms must be split and then joined to atoms of hydrogen.

Chemists call this process of taking atoms from the atmosphere and combining them into molecules useful to living things “fixing” that element. Until a German Jewish chemist named Fritz Haber figured out how to turn this trick in 1909, all the usable nitrogen on earth had at one time been fixed by soil bacteria living on the roots of leguminous plants (such as peas or alfalfa or locust trees) or, less commonly, by the shock of electrical lightning, which can break nitrogen bonds in the air, releasing a light rain of fertility.

In his book Enriching the Earth: Fritz Haber, Carl Bosch and the Transformation of World Food Production, Vaclav Smil pointed out that “there is no way to grow crops and human bodies without nitrogen.” Before Haber’s invention, the sheer amount of life earth could support–the size of crops and therefore the number of human bodies–was limited by the amount of nitrogen that bacteria and lightning could fix. By 1900, European scientists had recognized that unless a way was found to augment this naturally occurring nitrogen, the growth of the human population would soon grind to a very painful halt. The same recognition by Chinese scientists a few decades later is probably what compelled China’s opening to the West: after Nixon’s 1972 trip, the first major order the Chinese government placed was for 13 massive fertilizer factories. Without them, China would have starved.

This is why it may not be hyperbole to claim, as Smil does, that the Haber-Bosch process for fixing nitrogen (Bosch gets the credit for commercializing Haber’s idea) is the most important invention of the 20th century. He estimates that two of every five humans on earth today would not be alive if not for Fritz Haber’s invention. We can easily imagine a world without computers or electricity, Smil points out, but without synthetic fertilizer billions of people would never have been born. Though, as these numbers suggest, humans may have struck a Faustian bargain with nature when Fritz Haber gave us the power to fix nitrogen.

Fritz Haber? No, I’d never heard of him either, even though he was awarded the Nobel Prize in 1918 for “improving the standards of agriculture and the well-being of mankind.” But the reason for his obscurity has less to do with the importance of his work than an ugly twist of his biography, which recalls the dubious links between modern warfare and industrial agriculture: during World War I, Haber threw himself into the German war effort, and his chemistry kept alive Germany’s hopes for victory, by allowing it to make bombs from synthetic nitrate. Later, Haber put his genius for chemistry to work developing poison gases–ammonia, then chlorine. (He subsequently developed Zyklon B, the gas used in Hitler’s concentration camps.) His wife, a chemist sickened by her husband’s contribution to the war effort, used his army pistol to kill herself; Haber died, broken and in flight from Nazi Germany, in a Basel hotel room in 1934.

His story has been all but written out of the 20th century. But it embodies the paradoxes of science, the double edge to our manipulations of nature, the good and evil that can flow not only from the same man but from the same knowledge. Even Haber’s agricultural benefaction has proved to be a decidedly mixed blessing.

When humankind acquired the power to fix nitrogen, the basis of soil fertility shifted from a total reliance on the energy of the sun to a new reliance on fossil fuel. That’s because the Haber-Bosch process works by combining nitrogen and hydrogen gases under immense heat and pressure in the presence of a catalyst. The heat and pressure are supplied by prodigious amounts of electricity, and the hydrogen is supplied by oil, coal or, most commonly today, natural gas. True, these fossil fuels were created by the sun, billions of years ago, but they are not renewable in the same way that the fertility created by a legume nourished by sunlight is. (That nitrogen is fixed by a bacterium living on the roots of the legume, which trades a tiny drip of sugar for the nitrogen the plant needs.)

Liberated from the old biological constraints, the farm could now be managed on industrial principles, as a factory transforming inputs of raw material–chemical fertilizer–into outputs of corn. And corn adapted brilliantly to the new industrial regime, consuming prodigious quantities of fossil fuel energy and turning out ever more prodigious quantities of food energy. Growing corn, which from a biological perspective had always been a process of capturing sunlight to turn it into food, has in no small measure become a process of converting fossil fuels into food. More than half of all the synthetic nitrogen made today is applied to corn.

From the standpoint of industrial efficiency, it’s too bad we can’t simply drink petroleum directly, because there’s a lot less energy in a bushel of corn (measured in calories) than there is in the half-gallon of oil required to produce it. Ecologically, this is a fabulously expensive way to produce food–but “ecologically” is no longer the operative standard. In the factory, time is money, and yield is everything.

One problem with factories, as opposed to biological systems, is that they tend to pollute. Hungry for fossil fuel as hybrid corn is, farmers still feed it far more than it can possibly eat, wasting most of the fertilizer they buy. And what happens to that synthetic nitrogen the plants don’t take up? Some of it evaporates into the air, where it acidifies the rain and contributes to global warming. Some seeps down to the water table, whence it may come out of the tap. The nitrates in water bind to hemoglobin, compromising the blood’s ability to carry oxygen to the brain. (I guess I was wrong to suggest we don’t sip fossil fuels directly; sometimes we do.)

It has been less than a century since Fritz Haber’s invention, yet already it has changed earth’s ecology. More than half of the world’s supply of usable nitrogen is now man-made. (Unless you grew up on organic food, most of the kilo or so of nitrogen in your body was fixed by the Haber-Bosch process.) “We have perturbed the global nitrogen cycle,” Smil wrote, “more than any other, even carbon.” The effects may be harder to predict than the effects of the global warming caused by our disturbance of the carbon cycle, but they are no less momentous.

The flood of synthetic nitrogen has fertilized not just the farm fields but the forests and oceans, too, to the benefit of some species (corn and algae being two of the biggest beneficiaries) and to the detriment of countless others. The ultimate fate of the nitrates spread in Iowa or Indiana is to flow down the Mississippi into the Gulf of Mexico, where their deadly fertility poisons the marine ecosystem. The nitrogen tide stimulates the wild growth of algae, and the algae smother the fish, creating a “hypoxic,” or dead, zone as big as New Jersey–and still growing. By fertilizing the world, we alter the planet’s composition of species and shrink its biodiversity.

And yet, as organic farmers (who don’t use synthetic fertilizer) prove every day, the sun still shines, plants and their bacterial associates still fix nitrogen, and farm animals still produce vast quantities of nitrogen in their “waste,” so-called. It may take more work, but it’s entirely possible to nourish the soil, and ourselves, without dumping so much nitrogen into the environment. The key to reducing our dependence on synthetic nitrogen is to build a more diversified agriculture–rotating crops and using animals to recycle nutrients on farms–and give up our vast, nitrogen-guzzling monocultures of corn. Especially as the price of fossil fuels climbs, even the world’s most industrialized farmers will need to take a second look at how nature, and those who imitate her, go about creating fertility without diminishing our world.

In principle, making fuel from plants makes good sense. Instead of spewing fossilized carbon into the atmosphere, you’re burning the same carbon that a plant removed from the air only a few months earlier — so, theoretically, you’ve added no additional carbon. Sounds pretty green — and would be, if the plant you proposed to make the ethanol from were grown in a green way. But corn is not.

The way we grow corn in this country consumes tremendous quantities of fossil fuel. Corn receives more synthetic fertilizer than any other crop, and that fertilizer is made from fossil fuels — mostly natural gas. Corn also receives more pesticide than any other crop, and most of that pesticide is made from petroleum. To plow or disc the cornfields, plant the seed, spray the corn and harvest it takes large amounts of diesel fuel, and to dry the corn after harvest requires natural gas. So by the time your “green” raw material arrives at the ethanol plant, it is already drenched in fossil fuel. Every bushel of corn grown in America has consumed the equivalent of between a third and a half gallon of gasoline.

And that’s before you distill the corn into ethanol, an energy-intensive process that requires still more fossil fuel. Estimates vary, but they range from two-thirds to nine-tenths of a gallon of oil to produce a single gallon of ethanol. (The more generous number does not count all the energy costs of growing the corn.) Some estimates are still more dismal, suggesting it may actually take more than a gallon of fossil fuel to produce a gallon of our putative alternative to fossil fuel.

Making ethanol from corn makes no more sense from an economic point of view. The federal government offers a tax break of 54 cents for every gallon of ethanol produced, and this incentive is what has generated the enthusiasm for ethanol refining: the spigot of public money is open and the pigs are rushing to the trough. (At the same time, the government protects domestic ethanol producers by imposing a tariff of 54 cents a gallon on imported ethanol.) According to the Wall Street Journal, it will cost U.S. taxpayers $120 for every barrel of oil saved by making ethanol. Some “savings.” This is very good news indeed for Archer Daniels Midland, the agricultural processing company that controls about 30 percent of the ethanol market. (And, it would seem, a comparable percentage of the U.S. Congress, which has been showering the company with ethanol subsidies since the days when Bob Dole of Kansas was known as the senator from A.D.M.)

Absurd as it is, the rush to turn our corn surplus into ethanol appears unstoppable, and the corn belt, laboring under the weight of falling corn prices for the past several years, is celebrating the great good fortune of $3-a-gallon gas prices. We’re desperate for alternatives, and all that corn is waiting to be distilled. As corn prices rise (and the giddiness has already given them a bump), farmers will be tempted to produce yet more corn, which is not good news for the environment this whole deal is supposed to help. Why not? Because farmers will apply more nitrogen to boost yields (leading to more nitrogen pollution) and, since soy bean prices are down, they will be tempted to return to a “corn-on-corn” rotation. That is, rather than rotate their corn crops with soy beans (a legume that builds nitrogen in he soil), farmers will plant corn year after year, requiring still more synthetic nitrogen and doing long-term damage to the land.

It’s not easy being green.

But just because making ethanol from corn is an environmentally and economically absurd proposition doesn’t mean ethanol made from other plants is a bad idea. If you can make ethanol from a plant that doesn’t take so much energy to grow in the first place, the economics and energetics begin look a lot better. The Brazilians make ethanol from sugar cane, a perennial crop that doesn’t require nearly as much fossil fuel to grow. Switch grass, too, is a perennial crop that grows just about anywhere, requires little or no fertilizer and needs no plowing or annual replanting. And although the technology for making ethanol from grasses (cellulosic ethanol — distilled from plant cellulose rather than starch) is not quite there yet, it holds real potential.

So why the stampede to make ethanol from corn? Because we have so much of it, and such a powerful lobby promoting its consumption. Ethanol is just the latest chapter in a long, sorry history of clever and profitable schemes to dispose of surplus corn: there was corn liquor in the 19th century; feedlot meat starting in the 1950’s and, since 1980, high fructose corn syrup. We grow more than 10 billion bushels of corn a year in this country, far more than we can possibly eat — though God knows we’re doing our best, bingeing on corn-based fast food and high fructose corn syrup till we’re fat and diabetic. We probably can’t eat much more of the stuff without exploding, so the corn lobby is targeting the next unsuspecting beast that might help chomp through the surplus: your car.

One of the ballyhooed successes of the North American Free Trade Agreement has been the opening of Mexico to American farmers, who are now selling millions of bushels of corn south of the border. But why would Mexico, whose people still subsist on maize (mostly in tortillas), whose farmers still grow more maize than any other crop, ever buy corn from an American farmer? Because he can produce it much more cheaply than any Mexican farmer can. Actually that’s not quite right—it’s because he can sell it much more cheaply.

This is largely because of U.S. agricultural policies. While one part of the U.S. government speaks of the need to alleviate Third World poverty, another writing subsidy checks to American farmers, which encourages them to undersell Third World farmers.

The river of cheap American corn began flooding into Mexico after NAFTA took effect in 1994. Since then, the price of corn in Mexico has fallen by half. A 2003 report by the Carnegie Endowment says this flood has washed away 1.3 million small farmers. Unable to compete, they have left their land to join the swelling pools of Mexico’s urban unemployed. Others migrate to the U.S. to pick our crops—former farmers become day laborers.

The cheap U.S. corn has also wreaked havoc on Mexico’s land, according to the Carnegie report. The small farmers forced off their land often sell out to larger farmers who grow for export, farmers who must adopt far more industrial (and especially chemical- and water-intensive) practices to compete in the international marketplace. Fertilizer runoff into the Sea of Cortez starves its marine life of oxygen, and Mexico’s scarce water resources are leaching north, one tomato at a time.

Mexico’s industrial farmers now produce fruits and vegetables for American tables year-round. It’s ridiculous for a country like Mexico whose people are often hungry to use its best land to grow produce for a country where food is so abundant that its people are obese—but under free trade, it makes economic sense.

Meanwhile, the small farmers struggling to hold on in Mexico are forced to grow their corn on increasingly marginal lands, contributing to deforestation and soil erosion.

Compounding these environmental pressures is the advent of something new to Mexico: factory farming. The practice of feeding corn to livestock was actively discouraged by the Mexican government until quite recently—an expression of the culture’s quasi-religious reverence for maize. But those policies were reversed in 1994, and, just as it has done in the United States, cheap corn has driven the growth of animal feedlots, sewage concentration and water and air pollution.

Cheap American corn in Mexico threatens all corn—Zea mays itself—and by extension all of us who have come to depend on this plant. The small Mexican farmers who grow corn in southern Mexico are responsible for maintaining the genetic diversity of the species. While American farmers raise a small handful of genetically nearly identical hybrids, Mexico’s small farmers still grow hundreds of different, open-pollinated varieties, commonly called landraces.

This genetic diversity, the product of 10,000 years of human-maize co-evolution, represents some of the most precious and irreplaceable information on Earth, as we were reminded in 1970 when a fungus decimated the American corn crop and genes for resistance were found in a landrace in southern Mexico. These landraces will survive only as long as the farmers who cultivate them do. The cheap corn that is throwing these farmers off their land threatens to dry up the pool of genetic diversity on which the future of the species depends.

Perhaps from a strictly economic point of view, free trade in a commodity like corn appears eminently rational. But look at the same phenomenon from a biological point of view and it begins to look woefully shortsighted, if not mad.

Like the tulip, the apple and the potato, zea mays (the botanical name for both sweet and feed corn) has evolved with humans over the past 10,000 years in the great dance of species we call domestication. The plant gratifies human needs, in exchange for which humans expand the plant’s habitat, moving its genes all over the world and remaking the land (clearing trees, plowing the ground, protecting it from its enemies) so it might thrive.

Corn, by making itself tasty and nutritious, got itself noticed by Christopher Columbus, who helped expand its range from the New World to Europe and beyond. Today corn is the world’s most widely planted cereal crop. But nowhere have humans done quite as much to advance the interests of this plant as in North America, where zea mays has insinuated itself into our landscape, our food system—and our federal budget.

One need look no further than the $190 billion farm bill President Bush signed last month to wonder whose interests are really being served here. Under the 10-year program, taxpayers will pay farmers $4 billion a year to grow ever more corn, this despite the fact that we struggle to get rid of the surplus the plant already produces. The average bushel of corn (56 pounds) sells for about $2 today; it costs farmers more than $3 to grow it. But rather than design a program that would encourage farmers to plant less corn—which would have the benefit of lifting the price farmers receive for it—Congress has decided instead to subsidize corn by the bushel, thereby insuring that zea mays dominion over its 125,000-square-mile American habitat will go unchallenged.

At first blush this subsidy might look like a handout for farmers, but really it’s a form of welfare for the plant itself—and for all those economic interests that profit from its overproduction: the processors, factory farms, and the soft drink and snack makers that rely on cheap corn. For zea mays has triumphed by making itself indispensable not to farmers (whom it is swiftly and surely bankrupting) but to the Archer Daniels Midlands, Tysons and Coca-Colas of the world.

Our entire food supply has undergone a process of “cornification” in recent years, without our even noticing it. That’s because, unlike in Mexico, where a corn-based diet has been the norm for centuries, in the United States most of the corn we consume is invisible, having been heavily processed or passed through food animals before it reaches us. Most of the animals we eat (chickens, pigs and cows) today subsist on a diet of corn, regardless of whether it is good for them. In the case of beef cattle, which evolved to eat grass, a corn diet wreaks havoc on their digestive system, making it necessary to feed them antibiotics to stave off illness and infection. Even farm-raised salmon are being bred to tolerate corn—not a food their evolution has prepared them for. Why feed fish corn? Because it’s the cheapest thing you can feed any animal, thanks to federal subsidies. But even with more than half of the 10 billion bushels of corn produced annually being fed to animals, there is plenty left over. So companies like A.D.M., Cargill and ConAgra have figured ingenious new ways to dispose of it, turning it into everything from ethanol to Vitamin C and biodegradable plastics.

By far the best strategy for keeping zea mays in business has been the development of high-fructose corn syrup, which has all but pushed sugar aside. Since the 1980′s, most soft drink manufacturers have switched from sugar to corn sweeteners, as have most snack makers. Nearly 10 percent of the calories Americans consume now come from corn sweeteners; the figure is 20 percent for many children. Add to that all the corn-based animal protein (corn-fed beef, chicken and pork) and the corn qua corn (chips, muffins, sweet corn) and you have a plant that has become one of nature’s greatest success stories, by turning us (along with several other equally unwitting species) into an expanding race of corn eaters.

So why begrudge corn its phenomenal success? Isn’t this the way domestication is supposed to work?

The problem in corn’s case is that we’re sacrificing the health of both our bodies and the environment by growing and eating so much of it. Though we’re only beginning to understand what our cornified food system is doing to our health, there’s cause for concern. It’s probably no coincidence that the wholesale switch to corn sweeteners in the 1980′s marks the beginning of the epidemic of obesity and Type 2 diabetes in this country. Sweetness became so cheap that soft drink makers, rather than lower their prices, super-sized their serving portions and marketing budgets. Thousands of new sweetened snack foods hit the market, and the amount of fructose in our diets soared.

This would be bad enough for the American waistline, but there’s also preliminary research suggesting that high-fructose corn syrup is metabolized differently than other sugars, making it potentially more harmful. A recent study at the University of Minnesota found that a diet high in fructose (as compared to glucose) elevates triglyceride levels in men shortly after eating, a phenomenon that has been linked to an increased risk of obesity and heart disease. Little is known about the health effects of eating animals that have themselves eaten so much corn, but in the case of cattle, researchers have found that corn-fed beef is higher in saturated fats than grass-fed beef.

We know a lot more about what 80 million acres of corn is doing to the health of our environment: serious and lasting damage. Modern corn hybrids are the greediest of plants, demanding more nitrogen fertilizer than any other crop. Corn requires more pesticide than any other food crop. Runoff from these chemicals finds its way into the groundwater and, in the Midwestern corn belt, into the Mississippi River, which carries it to the Gulf of Mexico, where it has already killed off marine life in a 12,000-square-mile area.

To produce the chemicals we apply to our cornfields takes vast amounts of oil and natural gas. (Nitrogen fertilizer is made from natural gas, pesticides from oil.) America’s corn crop might look like a sustainable, solar-powered system for producing food, but it is actually a huge, inefficient, polluting machine that guzzles fossil fuel—a half a gallon of it for every bushel.

So it seems corn has indeed become king. We have given it more of our land than any other plant, an area more than twice the size of New York State. To keep it well fed and safe from predators we douse it with chemicals that poison our water and deepen our dependence on foreign oil. And then in order to dispose of all the corn this cracked system has produced, we eat it as fast as we can in as many ways as we can—turning the fat of the land into, well, fat. One has to wonder whether corn hasn’t at last succeeded in domesticating us.

You’ll be speeding down one of Finney County’s ramrod roads when the empty, dun-colored prairie suddenly turns black and geometric, an urban grid of steel-fenced rectangles as far as the eye can see—which in Kansas is really far. I say “suddenly,” but in fact a swiftly intensifying odor (an aroma whose Proustian echoes are more bus-station-men’s-room than cow-in-the-country) heralds the approach of a feedlot for more than a mile. Then it’s upon you: Poky Feeders, population 37,000. Cattle pens stretch to the horizon, each one home to 150 animals standing dully or lying around in a grayish mud that it eventually dawns on you isn’t mud at all. The pens line a network of unpaved roads that loop around vast waste lagoons on their way to the feedlot’s beating heart: a chugging, silvery feed mill that soars like an industrial cathedral over this teeming metropolis of meat.

I traveled to Poky early in January with the slightly improbable notion of visiting one particular resident: a young black steer that I’d met in the fall on a ranch in Vale, S.D. The steer, in fact, belonged to me. I’d purchased him as an 8-month-old calf from the Blair brothers, Ed and Rich, for $598. I was paying Poky Feeders $1.60 a day for his room, board and meds and hoped to sell him at a profit after he was fattened.

My interest in the steer was not strictly financial, however, or even gustatory, though I plan to retrieve some steaks from the Kansas packing plant where No. 534, as he is known, has an appointment with the stunner in June. No, my primary interest in this animal was educational. I wanted to find out how a modern, industrial steak is produced in America these days, from insemination to slaughter.

Eating meat, something I have always enjoyed doing, has become problematic in recent years. Though beef consumption spiked upward during the flush 90′s, the longer-term trend is down, and many people will tell you they no longer eat the stuff. Inevitably they’ll bring up mad-cow disease (and the accompanying revelation that industrial agriculture has transformed these ruminants into carnivores—indeed, into cannibals). They might mention their concerns about E. coli contamination or antibiotics in the feed. Then there are the many environmental problems, like groundwater pollution, associated with “Concentrated Animal Feeding Operations.” (The word “farm” no longer applies.) And of course there are questions of animal welfare. How are we treating the animals we eat while they’re alive, and then how humanely are we “dispatching” them, to borrow an industry euphemism?

Meat-eating has always been a messy business, shadowed by the shame of killing and, since Upton Sinclair’s writing of “The Jungle,” by questions about what we’re really eating when we eat meat. Forgetting, or willed ignorance, is the preferred strategy of many beef eaters, a strategy abetted by the industry. (What grocery-store item is more silent about its origins than a shrink-wrapped steak?) Yet I recently began to feel that ignorance was no longer tenable. If I was going to continue to eat red meat, then I owed it to myself, as well as to the animals, to take more responsibility for the invisible but crucial transaction between ourselves and the animals we eat. I’d try to own it, in other words.

So this is the biography of my cow.

The Blair brothers ranch occupies 11,500 acres of short-grass prairie a few miles outside Sturgis, S.D., directly in the shadow of Bear Butte. In November, when I visited, the turf forms a luxuriant pelt of grass oscillating yellow and gold in the constant wind and sprinkled with perambulating black dots: Angus cows and calves grazing.

Ed and Rich Blair run what’s called a “cow-calf” operation, the first stage of beef production, and the stage least changed by the modern industrialization of meat. While the pork and chicken industries have consolidated the entire life cycles of those animals under a single roof, beef cattle are still born on thousands of independently owned ranches. Although four giant meatpacking companies (Tyson’s subsidiary IBP, Monfort, Excel and National) now slaughter and market more than 80 percent of the beef cattle born in this country, that concentration represents the narrow end of a funnel that starts out as wide as the great plains.

The Blairs have been in the cattle business for four generations. Although there are new wrinkles to the process—artificial insemination to improve genetics, for example—producing beef calves goes pretty much as it always has, just faster. Calving season begins in late winter, a succession of subzero nights spent yanking breeched babies out of their bellowing mothers. In April comes the first spring roundup to work the newborn calves (branding, vaccination, castration); then more roundups in early summer to inseminate the cows ($15 mail-order straws of elite bull semen have pretty much put the resident stud out of work); and weaning in the fall. If all goes well, your herd of 850 cattle has increased to 1,600 by the end of the year.

My steer spent his first six months in these lush pastures alongside his mother, No. 9,534. His father was a registered Angus named GAR Precision 1,680, a bull distinguished by the size and marbling of his offspring’s rib-eye steaks. Born last March 13 in a birthing shed across the road, No. 534 was turned out on pasture with his mother as soon as the 80-pound calf stood up and began nursing. After a few weeks, the calf began supplementing his mother’s milk by nibbling on a salad bar of mostly native grasses: western wheatgrass, little bluestem, green needlegrass.

Apart from the trauma of the April day when he was branded and castrated, you could easily imagine No. 534 looking back on those six months grazing at his mother’s side as the good old days—if, that is, cows do look back. (“They do not know what is meant by yesterday or today,” Friedrich Nietzsche wrote, with a note of envy, of grazing cattle, “fettered to the moment and its pleasure or displeasure, and thus neither melancholy or bored.” Nietzsche clearly had never seen a feedlot.) It may be foolish to presume to know what a cow experiences, yet we can say that a cow grazing on grass is at least doing what he has been splendidly molded by evolution to do. Which isn’t a bad definition of animal happiness. Eating grass, however, is something that, after October, my steer would never do again.

Although the modern cattle industry all but ignores it, the reciprocal relationship between cows and grass is one of nature’s underappreciated wonders. For the grasses, the cow maintains their habitat by preventing trees and shrubs from gaining a foothold; the animal also spreads grass seed, planting it with its hoofs and fertilizing it. In exchange for these services, the grasses offer the ruminants a plentiful, exclusive meal. For cows, sheep and other grazers have the unique ability to convert grass—which single-stomached creatures like us can’t digest—into high-quality protein. They can do this because they possess a rumen, a 45-gallon fermentation tank in which a resident population of bacteria turns grass into metabolically useful organic acids and protein.

This is an excellent system for all concerned: for the grasses, for the animals and for us. What’s more, growing meat on grass can make superb ecological sense: so long as the rancher practices rotational grazing, it is a sustainable, solar-powered system for producing food on land too arid or hilly to grow anything else.

So if this system is so ideal, why is it that my cow hasn’t tasted a blade of grass since October? Speed, in a word. Cows raised on grass simply take longer to reach slaughter weight than cows raised on a richer diet, and the modern meat industry has devoted itself to shortening a beef calf’s allotted time on earth. “In my grandfather’s day, steers were 4 or 5 years old at slaughter,” explained Rich Blair, who, at 45, is the younger of the brothers by four years. “In the 50′s, when my father was ranching, it was 2 or 3. Now we get there at 14 to 16 months.” Fast food indeed. What gets a beef calf from 80 to 1,200 pounds in 14 months are enormous quantities of corn, protein supplements—and drugs, including growth hormones. These “efficiencies,” all of which come at a price, have transformed raising cattle into a high-volume, low-margin business. Not everybody is convinced that this is progress. “Hell,” Ed Blair told me, “my dad made more money on 250 head than we do on 850.”

Weaning marks the fateful moment when the natural, evolutionary logic represented by a ruminant grazing on grass bumps up against the industrial logic that, with stunning speed, turns that animal into a box of beef. This industrial logic is rational and even irresistible—after all, it has succeeded in transforming beef from a luxury item into everyday fare for millions of people. And yet the further you follow it, the more likely you are to wonder if that rational logic might not also be completely insane.

In early October, a few weeks before I met him, No. 534 was weaned from his mother. Weaning is perhaps the most traumatic time on a ranch for animals and ranchers alike; cows separated from their calves will mope and bellow for days, and the calves themselves, stressed by the change in circumstance and diet, are prone to get sick.

On many ranches, weaned calves go directly from the pasture to the sale barn, where they’re sold at auction, by the pound, to feedlots. The Blairs prefer to own their steers straight through to slaughter and to keep them on the ranch for a couple of months of “backgrounding” before sending them on the 500-mile trip to Poky Feeders. Think of backgrounding as prep school for feedlot life: the animals are confined in a pen, “bunk broken”—taught to eat from a trough—and gradually accustomed to eating a new, unnatural diet of grain. (Grazing cows encounter only tiny amounts of grain, in the form of grass seeds.)

It was in the backgrounding pen that I first met No. 534 on an unseasonably warm afternoon in November. I’d told the Blairs I wanted to follow one of their steers through the life cycle; Ed, 49, suggested I might as well buy a steer, as a way to really understand the daunting economics of modern ranching. Ed and Rich told me what to look for: a broad, straight back and thick hindquarters. Basically, you want a strong frame on which to hang a lot of meat. I was also looking for a memorable face in this Black Angus sea, one that would stand out in the feedlot crowd. Almost as soon as I started surveying the 90 or so steers in the pen, No. 534 moseyed up to the railing and made eye contact. He had a wide, stout frame and was brockle-faced—he had three distinctive white blazes. If not for those markings, Ed said, No. 534 might have been spared castration and sold as a bull; he was that good-looking. But the white blazes indicate the presence of Hereford blood, rendering him ineligible for life as an Angus stud. Tough break.

Rich said he would calculate the total amount I owed the next time No. 534 got weighed but that the price would be $98 a hundredweight for an animal of this quality. He would then bill me for all expenses (feed, shots, et cetera) and, beginning in January, start passing on the weekly “hotel charges” from Poky Feeders. In June we’d find out from the packing plant how well my investment had panned out: I would receive a payment for No. 534 based on his carcass weight, plus a premium if he earned a U.S.D.A. grade of choice or prime. “And if you’re worried about the cattle market,” Rich said jokingly, referring to its post-Sept. 11 slide, “I can sell you an option too.” Option insurance has become increasingly popular among cattlemen in the wake of mad-cow and foot-and-mouth disease.

Rich handles the marketing end of the business out of an office in Sturgis, where he also trades commodities. In fact you’d never guess from Rich’s unlined, indoorsy face and golfish attire that he was a rancher. Ed, by contrast, spends his days on the ranch and better looks the part, with his well-creased visage, crinkly cowboy eyes and ever-present plug of tobacco. His cap carries the same prairie-flat slogan I’d spotted on the ranch’s roadside sign: “Beef: It’s What’s for Dinner.”

My second morning on the ranch, I helped Troy Hadrick, Ed’s son-in-law and a ranch hand, feed the steers in the backgrounding pen. A thickly muscled post of a man, Hadrick is 25 and wears a tall black cowboy hat perpetually crowned by a pair of mirrored Oakley sunglasses. He studied animal science at South Dakota State and is up on the latest university thinking on cattle nutrition, reproduction and medicine. Hadrick seems to relish everything to do with ranching, from calving to wielding the artificial-insemination syringe.

Hadrick and I squeezed into the heated cab of a huge swivel-hipped tractor hooked up to a feed mixer: basically, a dump truck with a giant screw through the middle to blend ingredients. First stop was a hopper filled with Rumensin, a powerful antibiotic that No. 534 will consume with his feed every day for the rest of his life. Calves have no need of regular medication while on grass, but as soon as they’re placed in the backgrounding pen, they’re apt to get sick. Why? The stress of weaning is a factor, but the main culprit is the feed. The shift to a “hot ration” of grain can so disturb the cow’s digestive process—its rumen, in particular—that it can kill the animal if not managed carefully and accompanied by antibiotics.

After we’d scooped the ingredients into the hopper and turned on the mixer, Hadrick deftly sidled the tractor alongside the pen and flipped a switch to release a dusty tan stream of feed in a long, even line. No. 534 was one of the first animals to belly up to the rail for breakfast. He was heftier than his pen mates and, I decided, sparkier too. That morning, Hadrick and I gave each calf six pounds of corn mixed with seven pounds of ground alfalfa hay and a quarter-pound of Rumensin. Soon after my visit, this ration would be cranked up to 14 pounds of corn and 6 pounds of hay—and added two and a half pounds every day to No. 534.

While I was on the ranch, I didn’t talk to No. 534, pet him or otherwise try to form a connection. I also decided not to give him a name, even though my son proposed a pretty good one after seeing a snapshot. (“Night.”) My intention, after all, is to send this animal to slaughter and then eat some of him. No. 534 is not a pet, and I certainly don’t want to end up with an ox in my backyard because I suddenly got sentimental.

As fall turned into winter, Hadrick sent me regular e-mail messages apprising me of my steer’s progress. On Nov. 13 he weighed 650 pounds; by Christmas he was up to 798, making him the seventh-heaviest steer in his pen, an achievement in which I, idiotically, took a measure of pride. Between Nov. 13 and Jan. 4, the day he boarded the truck for Kansas, No. 534 put away 706 pounds of corn and 336 pounds of alfalfa hay, bringing his total living expenses for that period to $61.13. I was into this deal now for $659.

Hadrick’s e-mail updates grew chattier as time went on, cracking a window on the rancher’s life and outlook. I was especially struck by his relationship to the animals, how it manages to be at once intimate and unsentimental. One day Hadrick is tenderly nursing a newborn at 3 a.m., the next he’s “having a big prairie oyster feed” after castrating a pen of bull calves.

Hadrick wrote empathetically about weaning (“It’s like packing up and leaving the house when you are 18 and knowing you will never see your parents again”) and with restrained indignation about “animal activists and city people” who don’t understand the first thing about a rancher’s relationship to his cattle. Which, as Hadrick put it, is simply this: “If we don’t take care of these animals, they won’t take care of us.”

“Everyone hears about the bad stuff,” Hadrick wrote, “but they don’t ever see you give C.P.R. to a newborn calf that was born backward or bringing them into your house and trying to warm them up on your kitchen floor because they were born on a minus-20-degree night. Those are the kinds of things ranchers will do for their livestock. They take precedence over most everything in your life. Sorry for the sermon.”

To travel from the ranch to the feedlot, as No. 534 and I both did (in separate vehicles) the first week in January, feels a lot like going from the country to the big city. Indeed, a cattle feedlot is a kind of city, populated by as many as 100,000 animals. It is very much a premodern city, however—crowded, filthy and stinking, with open sewers, unpaved roads and choking air.

The urbanization of the world’s livestock is a fairly recent historical development, so it makes a certain sense that cow towns like Poky Feeders would recall human cities several centuries ago. As in 14th-century London, the metropolitan digestion remains vividly on display: the foodstuffs coming in, the waste streaming out. Similarly, there is the crowding together of recent arrivals from who knows where, combined with a lack of modern sanitation. This combination has always been a recipe for disease; the only reason contemporary animal cities aren’t as plague-ridden as their medieval counterparts is a single historical anomaly: the modern antibiotic.

I spent the better part of a day walking around Poky Feeders, trying to understand how its various parts fit together. In any city, it’s easy to lose track of nature—of the connections between various species and the land on which everything ultimately depends. The feedlot’s ecosystem, I could see, revolves around corn. But its food chain doesn’t end there, because the corn itself grows somewhere else, where it is implicated in a whole other set of ecological relationships. Growing the vast quantities of corn used to feed livestock in this country takes vast quantities of chemical fertilizer, which in turn takes vast quantities of oil—1.2 gallons for every bushel. So the modern feedlot is really a city floating on a sea of oil.

I started my tour at the feed mill, the yard’s thundering hub, where three meals a day for 37,000 animals are designed and mixed by computer. A million pounds of feed passes through the mill each day. Every hour of every day, a tractor-trailer pulls up to disgorge another 25 tons of corn. Around the other side of the mill, tanker trucks back up to silo-shaped tanks, into which they pump thousands of gallons of liquefied fat and protein supplement. In a shed attached to the mill sit vats of liquid vitamins and synthetic estrogen; next to these are pallets stacked with 50-pound sacks of Rumensin and tylosin, another antibiotic. Along with alfalfa hay and corn silage for roughage, all these ingredients are blended and then piped into the dump trucks that keep Poky’s eight and a half miles of trough filled.

The feed mill’s great din is made by two giant steel rollers turning against each other 12 hours a day, crushing steamed corn kernels into flakes. This was the only feed ingredient I tasted, and it wasn’t half bad; not as crisp as Kellogg’s, but with a cornier flavor. I passed, however, on the protein supplement, a sticky brown goop consisting of molasses and urea.

Corn is a mainstay of livestock diets because there is no other feed quite as cheap or plentiful: thanks to federal subsidies and ever-growing surpluses, the price of corn ($2.25 a bushel) is 50 cents less than the cost of growing it. The rise of the modern factory farm is a direct result of these surpluses, which soared in the years following World War II, when petrochemical fertilizers came into widespread use. Ever since, the U.S.D.A.’s policy has been to help farmers dispose of surplus corn by passing as much of it as possible through the digestive tracts of food animals, converting it into protein. Compared with grass or hay, corn is a compact and portable foodstuff, making it possible to feed tens of thousands of animals on small plots of land. Without cheap corn, the modern urbanization of livestock would probably never have occurred.

We have come to think of “cornfed” as some kind of old-fashioned virtue; we shouldn’t. Granted, a cornfed cow develops well-marbled flesh, giving it a taste and texture American consumers have learned to like. Yet this meat is demonstrably less healthy to eat, since it contains more saturated fat. A recent study in The European Journal of Clinical Nutrition found that the meat of grass-fed livestock not only had substantially less fat than grain-fed meat but that the type of fats found in grass-fed meat were much healthier. (Grass-fed meat has more omega 3 fatty acids and fewer omega 6, which is believed to promote heart disease; it also contains betacarotine and CLA, another “good” fat.) A growing body of research suggests that many of the health problems associated with eating beef are really problems with cornfed beef. In the same way ruminants have not evolved to eat grain, humans may not be well adapted to eating grain-fed animals. Yet the U.S.D.A.’s grading system continues to reward marbling—that is, intermuscular fat—and thus the feeding of corn to cows.

The economic logic behind corn is unassailable, and on a factory farm, there is no other kind. Calories are calories, and corn is the cheapest, most convenient source of calories. Of course the identical industrial logic—protein is protein—led to the feeding of rendered cow parts back to cows, a practice the F.D.A. banned in 1997 after scientists realized it was spreading mad-cow disease.

Make that mostly banned. The F.D.A.’s rules against feeding ruminant protein to ruminants make exceptions for “blood products” (even though they contain protein) and fat. Indeed, my steer has probably dined on beef tallow recycled from the very slaughterhouse he’s heading to in June. “Fat is fat,” the feedlot manager shrugged when I raised an eyebrow.

F.D.A. rules still permit feedlots to feed nonruminant animal protein to cows. (Feather meal is an accepted cattle feed, as are pig and fish protein and chicken manure.) Some public-health advocates worry that since the bovine meat and bone meal that cows used to eat is now being fed to chickens, pigs and fish, infectious prions could find their way back into cattle when they eat the protein of the animals that have been eating them. To close this biological loophole, the F.D.A. is now considering tightening its feed rules.

Until mad-cow disease, remarkably few people in the cattle business, let alone the general public, comprehended the strange semicircular food chain that industrial agriculture had devised for cattle (and, in turn, for us). When I mentioned to Rich Blair that I’d been surprised to learn that cows were eating cows, he said, “To tell the truth, it was kind of a shock to me too.” Yet even today, ranchers don’t ask many questions about feedlot menus. Not that the answers are so easy to come by. When I asked Poky’s feedlot manager what exactly was in the protein supplement, he couldn’t say. “When we buy supplement, the supplier says it’s 40 percent protein, but they don’t specify beyond that.” When I called the supplier, it wouldn’t divulge all its “proprietary ingredients” but promised that animal parts weren’t among them. Protein is pretty much still protein.

Compared with ground-up cow bones, corn seems positively wholesome. Yet it wreaks considerable havoc on bovine digestion. During my day at Poky, I spent an hour or two driving around the yard with Dr. Mel Metzen, the staff veterinarian. Metzen, a 1997 graduate of Kansas State’s vet school, oversees a team of eight cowboys who spend their days riding the yard, spotting sick cows and bringing them in for treatment. A great many of their health problems can be traced to their diet. “They’re made to eat forage,” Metzen said, “and we’re making them eat grain.”

Perhaps the most serious thing that can go wrong with a ruminant on corn is feedlot bloat. The rumen is always producing copious amounts of gas, which is normally expelled by belching during rumination. But when the diet contains too much starch and too little roughage, rumination all but stops, and a layer of foamy slime that can trap gas forms in the rumen. The rumen inflates like a balloon, pressing against the animal’s lungs. Unless action is promptly taken to relieve the pressure (usually by forcing a hose down the animal’s esophagus), the cow suffocates.

A corn diet can also give a cow acidosis. Unlike that in our own highly acidic stomachs, the normal pH of a rumen is neutral. Corn makes it unnaturally acidic, however, causing a kind of bovine heartburn, which in some cases can kill the animal but usually just makes it sick. Acidotic animals go off their feed, pant and salivate excessively, paw at their bellies and eat dirt. The condition can lead to diarrhea, ulcers, bloat, liver disease and a general weakening of the immune system that leaves the animal vulnerable to everything from pneumonia to feedlot polio.

Cows rarely live on feedlot diets for more than six months, which might be about as much as their digestive systems can tolerate. “I don’t know how long you could feed this ration before you’d see problems,” Metzen said; another vet said that a sustained feedlot diet would eventually “blow out their livers” and kill them. As the acids eat away at the rumen wall, bacteria enter the bloodstream and collect in the liver. More than 13 percent of feedlot cattle are found at slaughter to have abscessed livers.

What keeps a feedlot animal healthy—or healthy enough—are antibiotics. Rumensin inhibits gas production in the rumen, helping to prevent bloat; tylosin reduces the incidence of liver infection. Most of the antibiotics sold in America end up in animal feed—a practice that, it is now generally acknowledged, leads directly to the evolution of new antibiotic-resistant “superbugs.” In the debate over the use of antibiotics in agriculture, a distinction is usually made between clinical and nonclinical uses. Public-health advocates don’t object to treating sick animals with antibiotics; they just don’t want to see the drugs lose their efficacy because factory farms are feeding them to healthy animals to promote growth. But the use of antibiotics in feedlot cattle confounds this distinction. Here the drugs are plainly being used to treat sick animals, yet the animals probably wouldn’t be sick if not for what we feed them.

I asked Metzen what would happen if antibiotics were banned from cattle feed. “We just couldn’t feed them as hard,” he said. “Or we’d have a higher death loss.” (Less than 3 percent of cattle die on the feedlot.) The price of beef would rise, he said, since the whole system would have to slow down.

“Hell, if you gave them lots of grass and space,” he concluded dryly, “I wouldn’t have a job.”

Before heading over to Pen 43 for my reunion with No. 534, I stopped by the shed where recent arrivals receive their hormone implants. The calves are funneled into a chute, herded along by a ranch hand wielding an electric prod, then clutched in a restrainer just long enough for another hand to inject a slow-release pellet of Revlar, a synthetic estrogen, in the back of the ear. The Blairs’ pen had not yet been implanted, and I was still struggling with the decision of whether to forgo what is virtually a universal practice in the cattle industry in the United States. (It has been banned in the European Union.)

American regulators permit hormone implants on the grounds that no risk to human health has been proved, even though measurable hormone residues do turn up in the meat we eat. These contribute to the buildup of estrogenic compounds in the environment, which some scientists believe may explain falling sperm counts and premature maturation in girls. Recent studies have also found elevated levels of synthetic growth hormones in feedlot wastes; these persistent chemicals eventually wind up in the waterways downstream of feedlots, where scientists have found fish exhibiting abnormal sex characteristics.

The F.D.A. is opening an inquiry into the problem, but for now, implanting hormones in beef cattle is legal and financially irresistible: an implant costs $1.50 and adds between 40 and 50 pounds to the weight of a steer at slaughter, for a return of at least $25. That could easily make the difference between profit and loss on my investment in No. 534. Thinking like a parent, I like the idea of feeding my son hamburgers free of synthetic hormones. But thinking like a cattleman, there was really no decision to make.

I asked Rich Blair what he thought. “I’d love to give up hormones,” he said. “If the consumer said, We don’t want hormones, we’d stop in a second. The cattle could get along better without them. But the market signal’s not there, and as long as my competitor’s doing it, I’ve got to do it, too.”

Around lunch time, Metzen and I finally arrived at No. 534′s pen. My first impression was that my steer had landed himself a decent piece of real estate. The pen is far enough from the feed mill to be fairly quiet, and it has a water view—of what I initially thought was a reservoir, until I noticed the brown scum. The pen itself is surprisingly spacious, slightly bigger than a basketball court, with a concrete feed bunk out front and a freshwater trough in the back. I climbed over the railing and joined the 90 steers, which, en masse, retreated a few steps, then paused.

I had on the same carrot-colored sweater I’d worn to the ranch in South Dakota, hoping to jog my steer’s memory. Way off in the back, I spotted him—those three white blazes. As I gingerly stepped toward him, the quietly shuffling mass of black cowhide between us parted, and there No. 534 and I stood, staring dumbly at each other. Glint of recognition? None whatsoever. I told myself not to take it personally. No. 534 had been bred for his marbling, after all, not his intellect.

I don’t know enough about the emotional life of cows to say with any confidence if No. 534 was miserable, bored or melancholy, but I would not say he looked happy. I noticed that his eyes looked a little bloodshot. Some animals are irritated by the fecal dust that floats in the feedlot air; maybe that explained the sullen gaze with which he fixed me. Unhappy or not, though, No. 534 had clearly been eating well. My animal had put on a couple hundred pounds since we’d last met, and he looked it: thicker across the shoulders and round as a barrel through the middle. He carried himself more like a steer now than a calf, even though he was still less than a year old. Metzen complimented me on his size and conformation. “That’s a handsome looking beef you’ve got there.” (Aw, shucks.)

Staring at No. 534, I could picture the white lines of the butcher’s chart dissecting his black hide: rump roast, flank steak, standing rib, brisket. One way of looking at No. 534—the industrial way—was as an efficient machine for turning feed corn into beef. Every day between now and his slaughter date in June, No. 534 will convert 32 pounds of feed (25 of them corn) into another three and a half pounds of flesh. Poky is indeed a factory, transforming cheap raw materials into a less-cheap finished product, as fast as bovinely possible.

Yet the factory metaphor obscures as much as it reveals about the creature that stood before me. For this steer was not a machine in a factory but an animal in a web of relationships that link him to certain other animals, plants and microbes, as well as to the earth. And one of those other animals is us. The unnaturally rich diet of corn that has compromised No. 534′s health is fattening his flesh in a way that in turn may compromise the health of the humans who will eat him. The antibiotics he’s consuming with his corn were at that very moment selecting, in his gut and wherever else in the environment they wind up, for bacteria that could someday infect us and resist the drugs we depend on. We inhabit the same microbial ecosystem as the animals we eat, and whatever happens to it also happens to us.

I thought about the deep pile of manure that No. 534 and I were standing in. We don’t know much about the hormones in it—where they will end up or what they might do once they get there—but we do know something about the bacteria. One particularly lethal bug most probably resided in the manure beneath my feet. Escherichia coli 0157 is a relatively new strain of a common intestinal bacteria (it was first isolated in the 1980′s) that is common in feedlot cattle, more than half of whom carry it in their guts. Ingesting as few as 10 of these microbes can cause a fatal infection.

Most of the microbes that reside in the gut of a cow and find their way into our food get killed off by the acids in our stomachs, since they originally adapted to live in a neutral-pH environment. But the digestive tract of the modern feedlot cow is closer in acidity to our own, and in this new, manmade environment acid-resistant strains of E. coli have developed that can survive our stomach acids—and go on to kill us. By acidifying a cow’s gut with corn, we have broken down one of our food chain’s barriers to infection. Yet this process can be reversed: James Russell, a U.S.D.A. microbiologist, has discovered that switching a cow’s diet from corn to hay in the final days before slaughter reduces the population of E. coli 0157 in its manure by as much as 70 percent. Such a change, however, is considered wildly impractical by the cattle industry.

So much comes back to corn, this cheap feed that turns out in so many ways to be not cheap at all. While I stood in No. 534′s pen, a dump truck pulled up alongside the feed bunk and released a golden stream of feed. The animals stepped up to the bunk for their lunch. The $1.60 a day I’m paying for three giant meals is a bargain only by the narrowest of calculations. It doesn’t take into account, for example, the cost to the public health of antibiotic resistance or food poisoning by E. coli or all the environmental costs associated with industrial corn.

For if you follow the corn from this bunk back to the fields where it grows, you will find an 80-million-acre monoculture that consumes more chemical herbicide and fertilizer than any other crop. Keep going and you can trace the nitrogen runoff from that crop all the way down the Mississippi into the Gulf of Mexico, where it has created (if that is the right word) a 12,000-square-mile “dead zone.”

But you can go farther still, and follow the fertilizer needed to grow that corn all the way to the oil fields of the Persian Gulf. No. 534 started life as part of a food chain that derived all its energy from the sun; now that corn constitutes such an important link in his food chain, he is the product of an industrial system powered by fossil fuel. (And in turn, defended by the military—another uncounted cost of “cheap” food.) I asked David Pimentel, a Cornell ecologist who specializes in agriculture and energy, if it might be possible to calculate precisely how much oil it will take to grow my steer to slaughter weight. Assuming No. 534 continues to eat 25 pounds of corn a day and reaches a weight of 1,250 pounds, he will have consumed in his lifetime roughly 284 gallons of oil. We have succeeded in industrializing the beef calf, transforming what was once a solar-powered ruminant into the very last thing we need: another fossil-fuel machine.

Sometime in June, No. 534 will be ready for slaughter. Though only 14 months old, my steer will weigh more than 1,200 pounds and will move with the lumbering deliberateness of the obese. One morning, a cattle trailer from the National Beef plant in Liberal, Kan., will pull in to Poky Feeders, drop a ramp and load No. 534 along with 35 of his pen mates.

The 100-mile trip south to Liberal is a straight shot on Route 83, a two-lane highway on which most of the traffic consists of speeding tractor-trailers carrying either cattle or corn. The National Beef plant is a sprawling gray-and-white complex in a neighborhood of trailer homes and tiny houses a notch up from shanty. These are, presumably, the homes of the Mexican and Asian immigrants who make up a large portion of the plant’s work force. The meat business has made southwestern Kansas an unexpectedly diverse corner of the country.

A few hours after their arrival in the holding pens outside the factory, a plant worker will open a gate and herd No. 534 and his pen mates into an alley that makes a couple of turns before narrowing down to a single-file chute. The chute becomes a ramp that leads the animals up to a second-story platform and then disappears through a blue door.

That door is as close to the kill floor as the plant managers were prepared to let me go. I could see whatever I wanted to farther on—the cold room where carcasses are graded, the food-safety lab, the fabrication room where the carcasses are broken down into cuts—on the condition that I didn’t take pictures or talk to employees. But the stunning, bleeding and evisceration process was off limits to a journalist, even a cattleman-journalist like myself.

What I know about what happens on the far side of the blue door comes mostly from Temple Grandin, who has been on the other side and, in fact, helped to design it. Grandin, an assistant professor of animal science at Colorado State, is one of the most influential people in the United States cattle industry. She has devoted herself to making cattle slaughter less stressful and therefore more humane by designing an ingenious series of cattle restraints, chutes, ramps and stunning systems. Grandin is autistic, a condition she says has allowed her to see the world from the cow’s point of view. The industry has embraced Grandin’s work because animals under stress are not only more difficult to handle but also less valuable: panicked cows produce a surge of adrenaline that turns their meat dark and unappetizing. “Dark cutters,” as they’re called, sell at a deep discount.

Grandin designed the double-rail conveyor system in use at the National Beef plant; she has also audited the plant’s killing process for McDonald’s. Stories about cattle “waking up” after stunning only to be skinned alive prompted McDonald’s to audit its suppliers in a program that is credited with substantial improvements since its inception in 1999. Grandin says that in cattle slaughter “there is the pre-McDonald’s era and the post-McDonald’s era—it’s night and day.”

Grandin recently described to me what will happen to No. 534 after he passes through the blue door. “The animal goes into the chute single file,” she began. “The sides are high enough so all he sees is the butt of the animal in front of him. As he walks through the chute, he passes over a metal bar, with his feet on either side. While he’s straddling the bar, the ramp begins to decline at a 25-degree angle, and before he knows it, his feet are off the ground and he’s being carried along on a conveyor belt. We put in a false floor so he can’t look down and see he’s off the ground. That would panic him.”

Listening to Grandin’s rather clinical account, I couldn’t help wondering what No. 534 would be feeling as he approached his end. Would he have any inkling—a scent of blood, a sound of terror from up the line—that this was no ordinary day?

Grandin anticipated my question: “Does the animal know it’s going to get slaughtered? I used to wonder that. So I watched them, going into the squeeze chute on the feedlot, getting their shots and going up the ramp at a slaughter plant. No difference. If they knew they were going to die, you’d see much more agitated behavior.

“Anyway, the conveyor is moving along at roughly the speed of a moving sidewalk. On a catwalk above stands the stunner. The stunner has a pneumatic-powered ‘gun’ that fires a steel bolt about seven inches long and the diameter of a fat pencil. He leans over and puts it smack in the middle of the forehead. When it’s done correctly, it will kill the animal on the first shot.”

For a plant to pass a McDonald’s audit, the stunner needs to render animals “insensible” on the first shot 95 percent of the time. A second shot is allowed, but should that one fail, the plant flunks. At the line speeds at which meatpacking plants in the United States operate—390 animals are slaughtered every hour at National, which is not unusual—mistakes would seem inevitable, but Grandin insists that only rarely does the process break down.

“After the animal is shot while he’s riding along, a worker wraps a chain around his foot and hooks it to an overhead trolley. Hanging upside down by one leg, he’s carried by the trolley into the bleeding area, where the bleeder cuts his throat. Animal rights people say they’re cutting live animals, but that’s because there’s a lot of reflex kicking.” This is one of the reasons a job at a slaughter plant is the most dangerous in America. “What I look for is, Is the head dead? It should be flopping like a rag, with the tongue hanging out. He’d better not be trying to hold it up—then you’ve got a live one on the rail.” Just in case, Grandin said, “they have another hand stunner in the bleed area.”

Much of what happens next—the de-hiding of the animal, the tying off of its rectum before evisceration—is designed to keep the animal’s feces from coming into contact with its meat. This is by no means easy to do, not when the animals enter the kill floor smeared with manure and 390 of them are eviscerated every hour. (Partly for this reason, European plants operate at much slower line speeds.) But since that manure is apt to contain lethal pathogens like E. coli 0157, and since the process of grinding together hamburger from hundreds of different carcasses can easily spread those pathogens across millions of burgers, packing plants now spend millions on “food safety”—which is to say, on the problem of manure in meat.

Most of these efforts are reactive: it’s accepted that the animals will enter the kill floor caked with feedlot manure that has been rendered lethal by the feedlot diet. Rather than try to alter that diet or keep the animals from living in their waste or slow the line speed—all changes regarded as impractical—the industry focuses on disinfecting the manure that will inevitably find its way into the meat. This is the purpose of irradiation (which the industry prefers to call “cold pasteurization”). It is also the reason that carcasses pass through a hot steam cabinet and get sprayed with an antimicrobial solution before being hung in the cooler at the National Beef plant.

It wasn’t until after the carcasses emerged from the cooler, 36 hours later, that I was allowed to catch up with them, in the grading room. I entered a huge arctic space resembling a monstrous dry cleaner’s, with a seemingly endless overhead track conveying thousands of red-and-white carcasses. I quickly learned that you had to move smartly through this room or else be tackled by a 350-pound side of beef. The carcasses felt cool to the touch, no longer animals but meat.

Two by two, the sides of beef traveled swiftly down the rails, six pairs every minute, to a station where two workers—one wielding a small power saw, the other a long knife—made a single six-inch cut between the 12th and 13th ribs, opening a window on the meat inside. The carcasses continued on to another station, where a U.S.D.A. inspector holding a round blue stamp glanced at the exposed rib eye and stamped the carcass’s creamy white fat once, twice or—very rarely—three times: select, choice, prime.

For the Blair brothers, and for me, this is the moment of truth, for that stamp will determine exactly how much the packing plant will pay for each animal and whether the 14 months of effort and expense will yield a profit.

Unless the cattle market collapses between now and June (always a worry these days), I stand to make a modest profit on No. 534. In February, the feedlot took a sonogram of his rib eye and ran the data through a computer program. The projections are encouraging: a live slaughter weight of 1,250, a carcass weight of 787 pounds and a grade at the upper end of choice, making him eligible to be sold at a premium as Certified Angus Beef. Based on the June futures price, No. 534 should be worth $944. (Should he grade prime, that would add another $75.)

I paid $598 for No. 534 in November; his living expenses since then come to $61 on the ranch and $258 for 160 days at the feedlot (including implant), for a total investment of $917, leaving a profit of $27. It’s a razor-thin margin, and it could easily vanish should the price of corn rise or No. 534 fail to make the predicted weight or grade—say, if he gets sick and goes off his feed. Without the corn, without the antibiotics, without the hormone implant, my brief career as a cattleman would end in failure.

The Blairs and I are doing better than most. According to Cattle-Fax, a market-research firm, the return on an animal coming out of a feedlot has averaged just $3 per head over the last 20 years.

“Some pens you make money, some pens you lose,” Rich Blair said when I called to commiserate. “You try to average it out over time, limit the losses and hopefully make a little profit.” He reminded me that a lot of ranchers are in the business “for emotional reasons—you can’t be in it just for the money.”

Now you tell me.

The manager of the packing plant has offered to pull a box of steaks from No. 534 before his carcass disappears into the trackless stream of commodity beef fanning out to America’s supermarkets and restaurants this June. From what I can see, the Blair brothers, with the help of Poky Feeders, are producing meat as good as any you can find in an American supermarket. And yet there’s no reason to think this steak will taste any different from the other high-end industrial meat I’ve ever eaten.

While waiting for my box of meat to arrive from Kansas, I’ve explored some alternatives to the industrial product. Nowadays you can find hormone- and antibiotic-free beef as well as organic beef, fed only grain grown without chemicals. This meat, which is often quite good, is typically produced using more grass and less grain (and so makes for healthier animals). Yet it doesn’t fundamentally challenge the corn-feedlot system, and I’m not sure that an “organic feedlot” isn’t, ecologically speaking, an oxymoron. What I really wanted to taste is the sort of preindustrial beef my grandparents ate—from animals that have lived most of their full-length lives on grass.

Eventually I found a farmer in the Hudson Valley who sold me a quarter of a grass-fed Angus steer that is now occupying most of my freezer. I also found ranchers selling grass-fed beef on the Web; Eatwild.com is a clearinghouse of information on grass-fed livestock, which is emerging as one of the livelier movements in sustainable agriculture.

I discovered that grass-fed meat is more expensive than supermarket beef. Whatever else you can say about industrial beef, it is remarkably cheap, and any argument for changing the system runs smack into the industry’s populist arguments. Put the animals back on grass, it is said, and prices will soar; it takes too long to raise beef on grass, and there’s not enough grass to raise them on, since the Western range lands aren’t big enough to sustain America’s 100 million head of cattle. And besides, Americans have learned to love cornfed beef. Feedlot meat is also more consistent in both taste and supply and can be harvested 12 months a year. (Grass-fed cattle tend to be harvested in the fall, since they stop gaining weight over the winter, when the grasses go dormant.)

All of this is true. The economic logic behind the feedlot system is hard to refute. And yet so is the ecological logic behind a ruminant grazing on grass. Think what would happen if we restored a portion of the Corn Belt to the tall grass prairie it once was and grazed cattle on it. No more petrochemical fertilizer, no more herbicide, no more nitrogen runoff. Yes, beef would probably be more expensive than it is now, but would that necessarily be a bad thing? Eating beef every day might not be such a smart idea anyway—for our health, for the environment. And how cheap, really, is cheap feedlot beef? Not cheap at all, when you add in the invisible costs: of antibiotic resistance, environmental degradation, heart disease, E. coli poisoning, corn subsidies, imported oil and so on. All these are costs that grass-fed beef does not incur.

So how does grass-fed beef taste? Uneven, just as you might expect the meat of a nonindustrial animal to taste. One grass-fed tenderloin from Argentina that I sampled turned out to be the best steak I’ve ever eaten. But unless the meat is carefully aged, grass-fed beef can be tougher than feedlot beef—not surprisingly, since a grazing animal, which moves around in search of its food, develops more muscle and less fat. Yet even when the meat was tougher, its flavor, to my mind, was much more interesting. And specific, for the taste of every grass-fed animal is inflected by the place where it lived. Maybe it’s just my imagination, but nowadays when I eat a feedlot steak, I can taste the corn and the fat, and I can see the view from No. 534′s pen. I can’t taste the oil, obviously, or the drugs, yet now I know they’re there.

A considerably different picture comes to mind while chewing (and, O.K., chewing) a grass-fed steak: a picture of a cow outside in a pasture eating the grass that has eaten the sunlight. Meat-eating may have become an act riddled with moral and ethical ambiguities, but eating a steak at the end of a short, primordial food chain comprising nothing more than ruminants and grass and light is something I’m happy to do and defend. We are what we eat, it is often said, but of course that’s only part of the story. We are what what we eat eats too.

But this is not the only kind of information encoded in a garden seed. For the seeds I order are inscribed with cultural, political and economic information as well. And if I am to believe some of the more polemical seedsmen whose catalogues-cum-tracts have found their way to my mailbox this season, the decision to plant one variety and not another is freighted with moral and environmental significance. A political fight is not exactly what I came to vegetable gardening to pick, but I seem to have stumbled into one anyway.

There I was, looking for a new variety of corn to try, and I wind up reading in the catalogue from Seeds of Change—part of a growing army of seed firms fired with a sense of political mission—about the negative impact that the General Agreement on Tariffs and Trade (GATT), of all things, will have on the free exchange of seeds and global biodiversity. Then Seeds Blum, a boppy counterculture catalogue published in Boise, Idaho, buttonholes me to explain that by planting modern hybrids, I am helping multinational corporations to monopolize the gene pool. And J. L. Hudson, Seedsman, who publishes the somewhat forbidding Ethnobotanical Catalogue of Seeds, preaches that by planting traditional nonhybrid seeds in my garden I can help to preserve cultural as well as genetic diversity.

The alternative seed catalogues paint the “F-1″ hybrid, in particular, as an environmental menace and make a point of refusing to handle the dread seed. In the last few decades F-1 hybrids, which are simply the first generation produced by the crossing of two plant varieties, have become the stock in trade of the commercial seed industry, and they are gradually crowding traditional “open pollinated” varieties (ones pollinated by bees, birds or wind instead of plant geneticists) out of the marketplace. According to the Seed Savers Exchange, an organization established in 1975 to encourage backyard gardeners to preserve certain open-pollinated varieties, almost half of all the nonhybrid vegetable varieties on the market just 10 years ago have been dropped from mail-order catalogues. This often results in extinction, since many domesticated species will not survive unless they are planted over and over again by humans. W. Atlee Burpee & Company would tell you that the disappearance of traditional varieties is simply the Darwinian operation of the marketplace: if the old varieties were any good, they’d compete more successfully. In fact the chairman of Burpee made exactly that argument last spring in a Times Op-Ed piece in defense of the embattled hybrid, likening open-pollinated seeds to Model T’s.

The seed savers see another, darker reason for the hybrid’s predominance. As the Seeds Blum catalogue puts it, in words plain as those of Marx and Engels, “The reason hybrids exist is to protect the breeding investment of the seed company.” Unlike the seeds of open-pollinated varieties, the seeds produced by an F-1 hybrid plant don’t “come true”—their offspring are apt to exhibit the undesirable traits of one or the other parent. In other words, seeds of these hybrids can’t be saved or reproduced; their biology makes them proprietary. By forcing gardeners and farmers to return for new seeds each season, the companies selling F-1 hybrids have effectively taken control of the means of production.

These are not the only ways in which modern hybrids remake nature in the image of capitalism. Given heavy doses of fertilizer, F-1 hybrids grow swiftly and produce high yields. They also produce genetically uniform plants. What could better suit factory farming than a robust field of identical tomato or corn plants genetically coded to ripen all at once, thereby facilitating mechanical harvesting?

But the same uniformity that smoothes capitalism’s way into the farm and garden also violates one of nature’s cardinal principles: genetic diversity. A field of genetically identical plants is much more vulnerable to disease, as American corn farmers discovered in 1970 when a blight decimated the nation’s crop, which had grown dependent on a few genetically similar hybrids. After such blights, breeders have historically turned to traditional varieties of corn, found in places like Mexico, to refresh the gene pool and provide new resistance. But what happens when Mexican farmers have been sold on fancy new hybrids and their traditional varieties have become extinct?

Seeds of Change claims in its catalogue that, second to destruction of habitats, “possibly the biggest single trigger of extinctions is the introduction of hybrid seeds.” This sounds like hyperbole, and yet the seed insurgents are probably right to perceive a threat to biodiversity in the commercial seed trade’s promotion of hybrids. We’re accustomed to think of biodiversity only in connection with wild species in places like the rain forest, but the species that humans have selected and bred since the invention of agriculture are no less important. They represent a priceless worldwide store of genetic and cultural information, the heritage of some 10,000 years of coevolution between humans and their crop plants.

As the seed savers see it, the battle for the survival and control of that heritage is about to intensify. The promise of genetic engineering has set off a “gene rush” as breeders seek to identify and control plant genes for a variety of traits—resistance to disease or frost, say, or to weed-killing chemicals. At the same time, under the new GATT accords, which will be phased in over the next five years, the world will take a giant step toward the privatization of seeds. That’s because the GATT provisions on “intellectual property rights” require all signatories—many for the first time—to set up a system for the patenting of plant varieties.

This development has already ignited powerful protests in the third world. Many farmers worry that by promoting F-1 hybrids and patenting local plant varieties that were previously saved and exchanged freely, multinational corporations will ruin traditional agriculture. Last July a group of Indian farmers destroyed a Cargill seed-processing plant under construction in southern India, the second attack on the American seed giant’s facilities there. (During the first, in December 1992, 300 protesters broke into Cargill’s office in Bangalore and made a bonfire of corporate documents.) And in October, in what may be the largest protest ever against GATT, more than 500,000 farmers in India rallied in defense of their “sovereignty over seeds.” Though it has gone virtually unreported in this country, India’s “seed satyagraha” suggests that freedom of seeds is becoming a point of sharp contention between North and South.

SEEDS OF CHANGE, WHOSE LATEST CATALOGUE brings news of this seed savers Boston Tea Party, bids me to see a connection between my garden and the freedom and diversity of the world seed trade. Take the packet of corn seeds I’m in the market for. What I’m really in the market for, the catalogue makes clear, is a particular set of corn genes, and the choice I make will constitute a kind of evolutionary vote. I could, for example, order a hybrid from Burpee. This year I see they’re offering several of the modern “supersweet” hybrids (several years ago some university researchers figured out how to double the gene for sugar in corn and slow its conversion to starch), including Illini Xtra-Sweet, which the catalogue claims is “four times as sweet as standard hybrids 48 hours after picking!” This is a revealing boast. It suggests that Illini Xtra-Sweet and hybrids like it were developed with factory farmers rather than backyard gardeners in mind. For what gardener would need a corn that holds its sweetness for two days?

To order Illini Xtra-Sweet would be a vote not just for a particular kind of corn but for a kind of agriculture—indeed, for a kind of culture. You could probably deduce a great deal about contemporary America from the genes of Illini Xtra-Sweet; for example, that this is the product of a capitalist economy whose farms rely on petrochemicals (which most hybrids require to thrive) and are typically located a long truck ride away from their consumers, who prize sweetness over nutrition and tend to boil rather than roast their corn. (New corn hybrids have been bred for sweetness and tenderness, usually at the expense of nutritional value.)

The alternative seed catalogues brim with unusual varieties whose genes encode whole different cultures and culinary possibilities that seem worth experiencing—and helping to preserve. From Seeds of Change I can order Black Aztec, said to be a pre-Columbian Aztec variety that does well in poor, dry soils and whose kernels stand up well to roasting. (At maturity the kernels turn blue black and can be ground into a highly nutritious cornmeal.) Seeds Blum recommends Trucker’s Favorite, an heirloom “dent corn” that supposedly makes up in corn flavor what it lacks in sweetness and looks. J. L. Hudson, the most radical of the seedsmen, offers several native American field corns whose appeal seems distinctly less gustatory than, well, ethnobotanical (but then J. L. Hudson believes that we work for the seeds rather than the other way around). This year he’s carrying Pod Corn, an ancestral strain whose every kernel is encased in its own husk, and Mandan Bride, “a beautiful multicolor corn said to be from the Mandan people in what is now called North Dakota.”

Hudson’s catalog is such a vast, teeming democracy of seeds that it makes room for common weeds such as mullein and burdock, four varieties of leaf tobacco (including one grown by Zapotec Indians), even seeds for giant sequoia trees. As one of his cranky, enlightening catalogue essays makes clear, Hudson believes in preserving human as well as genetic diversity—hence the Zapotec tobacco and the Mandan Bride corn, both of whose genes encode specific cultural practices he’s bent on saving. And who knows, one of the old Indian varieties he carries might turn out to contain a trait we will desperately need someday, perhaps the gene that will help us adapt corn to a warmer, drier climate.

That’s the wager J. L. Hudson and his fellow seed insurgents are urging me to make—to turn a corner of my garden into a kind of botanical ark, a blooming, fruiting archive of genetic and cultural information, a multicultural free-port city of open-pollinated, public-domain seeds to be saved and freely disseminated, Burpee and Cargill and GATT be damned! Hudson, Seeds of Change and Seeds Blum hold out a powerful, beguiling and wildly ambitious vision of the garden—and yet it awaits nothing more than a handful of seeds.

I’m expecting my packet of Black Aztecs in the mail any day now.