Deadly Harvest: The Intimate Relationship Between Our Heath and Our Food (8 page)

The earliest farmers used hoes to till the ground. But as soon as they had domesticated cattle, oxen were available as a source of power. So, some ingenious person invented the first plows. They were already in use 5,000 years ago in present-day southern Iraq. The technique quickly spread to everywhere in the Fertile Crescent, including Israel and Egypt. The earliest known use in China is more recent, about 2,500 years ago. This basic plowing technique hardly changed for several thousand years although there were gradual improvements: more efficient plows were devised and draft animals became bigger and more powerful. Most farming centers followed this pattern, but in the Americas, no suitable animals were available, so the Aztecs and Incas continued to cultivate by hand.

The first farmers had to grind their cereal grains into flour. They did this with a device called a quern, which consisted of a flat stone with a rounded stone on top. A few grains were put between the two stones and someone pushed the rounded stone backwards and forwards to pulverize the grains into coarse flour. By Roman times, the quern had become a much bigger, rotary device operated by slaves or donkeys. About this time, there was an important advance: nature, in the form of flowing water, was harnessed to turn the millstones. These early “watermills” were built of wood including all the mechanism. In some areas where free flowing water was not readily available (for example, Holland), the watermill technology was adapted to harness wind power; thus the windmill was born. The technology improved steadily over the ensuing centuries. It took steam power during the Industrial Revolution to replace these mills during the 19th century.

The late Middle Ages in northern Europe saw two big leaps in farming practices. In England and Germany, it was discovered how to get three crops every two years instead of just two crops. This is known as the three-field system: one-third was planted in the fall for harvesting early summer, one-third in the spring for harvesting in late summer, and one-third remained fallow. This increased production by 50%. Mediterranean countries like Italy, Greece, and Spain could not benefit from this innovation: unlike northern Europe, they do not have summer rain, which is essential for the system to work.

Secondly, the problem of feeding livestock during the hard winters held back northern Europe. The practice was to slaughter a large part of the herd in autumn and start again in the spring. The three-field system generated a surplus of fodder that farmers could feed to the beasts through the winter. But this could only work if there was a good way of preserving the fodder for several months. This led to a second major development—silage, a way of conserving fodder in deep pits and allowing it to ferment. This stops it from going rotten and preserves its nutrients. These two developments marked the rise in economic power of northern Europe during the Middle Ages to the detriment of the countries of southern Europe.

So, farming techniques improved, at least in the sense that farmers obtained higher production for the same effort. Farming had evolved in a slow and steady way from its early roots and most of the basic principles would have been familiar to a Sumerian from 5,000 years earlier. During all this time, no one knew what was happening to the nutrients in the plants and animals, but no one really thought about it either. They were being kept alive in an uncertain world and survival was the goal.

Plant Chemicals

In spite of 5,000 years of gradual improvement, there was one big area that remained a problem: the loss of crops to diseases and pests of all kinds. It was not until the 19th century that a pest was successfully controlled on a large scale. This was an infestation of vines in the 1840s by a kind of mildew and it was cleared up by dusting with sulfur. However, advances on this front were slow. It took another century before the agricultural world was turned upside down by a discovery by Paul Müller, a Swiss chemist. In 1942, he developed the highly effective and long-lasting insecticide DDT. DDT’s ability to kill just about every insect, yet leave plants and warm-blooded animals apparently unharmed, was so successful that Müller received the Nobel Prize in 1948.

Research on poison gas in Germany during World War II led to the discovery of another group of yet more powerful insecticides—the most common being a compound called parathion. Some of these compounds were “systemic”—that is, the plant absorbed them into its tissues and became itself toxic to insects. Though low in cost, these compounds were toxic to humans and other warm-blooded animals.

These chemicals were designed to kill insects. However, there are other nuisances that harm crop yields: funguses, weeds, worms and viruses. Attention was turned to developing fungicides, herbicides (to kill weeds), and vermicides (to kill worms), with almost equal success. Viruses cannot be attacked by chemicals, but they are transmitted from plant to plant by insects, worms, and other bugs; by killing the bugs, virus damage was controlled too. It seemed that almost any pest, disease, or weed problem could be mastered by suitable chemical treatment. Farmers foresaw a pest-free millennium. Crop losses were cut sharply, locust attack was reduced to a manageable problem, and the new chemicals, by dramatically improving food production, saved the lives of millions of people.

But problems began surfacing in the early 1950s. In many crops, standard doses of DDT, parathion, and similar pesticides were found ineffective and had to be doubled or trebled. Resistant breeds of insects had developed. In addition, the powerful insecticides often destroyed helpful insects too. Resistant survivors soon produced worse outbreaks of pests than there had been before the treatment.

Soon, concern was expressed about pesticide residues. It was found that many birds and wild mammals retained considerable quantities of DDT in their bodies. Rachel Carson, in her 1962 book
Silent Spring
, sounded the alarm. Since that time, agriculturalists have tried to find a middle way between the well-tried traditional methods and the use of chemicals. Even so, chemicals have become ever more sophisticated and widespread, and they are not just restricted to controlling pests either. Fruit trees are sprayed to heighten the color of the fruit; they are even treated with hormones to get all the fruit ready for harvesting on a programmed day. Residues in foods are strictly controlled, but there are always some left on our plates. No one really knows the consequences of consuming them over a lifetime or the effect they have when they are added to each other.

Plant Fertilizers

The ancient techniques of enriching the ground with manure had been known for a very long time. However, it was not until the 18th century that a chemical found naturally in India, saltpeter, was used to fertilize fields in England. Ground up bones, especially if treated with sulfuric acid, were found to be useful too. All kinds of other materials were tried, such as powdered gypsum and blast furnace slag, but one of the most successful was guano. Guano is a massive thick deposit of bird droppings accumulated over the centuries in the Peruvian Lobos Islands.

It took a while for anyone to work out why these materials had their effect. Then, the brilliant English chemist Sir Humphry Davy, in an 1820 treatise, explained just what these fertilizers were doing. They were adding three bulk elements essential for plant growth: nitrogen, potassium, and phosphorus. Deposits of phosphorus and potassium were discovered in many parts of the world and their availability, even up to the present day, is not a problem. Sources of nitrogen (as in saltpeter) were scarce and its supply was not assured until, in 1909, the German chemist Fritz Haber discovered how to make nitrogen fertilizer from the nitrogen in the air. These three chemicals—nitrogen, potassium and phosphorus—still form the basis of all bulk fertilizers.

Plants grow in soil that contains a vast range of chemicals and they absorb them, even if they don’t need them. Over the years, scientists have identified those other elements that are essential to a healthy plant. They are needed in much smaller quantities (so they are known as “trace elements”) and there are only about 14 of them. They include chemicals like copper, zinc, manganese, and sulfur. With this discovery, it was possible to grow plants without soil altogether, just dangling their roots in nutrient-rich water. This system is known variously as “hydroponics,” “nutriculture,” and “soil-less culture.” A variant is used extensively in desert areas where plants can be grown, under suitable cover, with their roots in gravel or sand. Beautiful vegetables and fruit can be grown this way by just using these basic nutrients. However, what makes a plant grow is not always sufficient for animals and humans. We need those other trace elements that plants normally absorb when they grow in soil, such as iron, chromium, and selenium, even if the plants themselves do not need them.

Animal Husbandry

In parallel with the developments in pest control since World War II, animal husbandry was under examination. It is expensive allowing cattle, hogs, and chickens to roam freely, feeding as they choose. Much better to restrict their movements and give them feed that is designed to make them grow faster, fatter, and with less waste. Proteins, fats, and carbohydrates are the basic elements of animal nutrition, so does it matter where they come from? Yes, indeed it does. For example, cows’ natural food is found by browsing in trees and bushes. This might come as a surprise, because we think of cows sitting in a grassy meadow chewing the cud. It was only at the end of the Middle Ages when herdsmen discovered that, by feeding cows on “high energy” grass pastures, they would grow more quickly. We now know that this restricted, single-food diet changes the nutritional quality of the meat.

But cattlemen have gone one step further: corn is plentiful and easily made into a concentrated feed, and it fattens cows fast. But corn is not normal cow food at all—they cannot digest it properly and it disrupts the working of their intestines. Their colons become overgrown with bacteria, which in turn produce nasty toxins that get into the carcass. Cattlemen even have a name for this phenomenon: “bloody gut.” Ever cheaper sources of fodder were sought, however outlandish. Even the last swillings from the slaughterhouse floor were collected, dried, and pressed into cake as animal feed. In this way, we were treated to the ultimate spectacle of dead cows being fed to live cows. This practice allowed the incurable sickness bovine spongiform encephalopathy (BSE; familiarly known as “mad cow disease”) to spread in British herds and to fatally sicken many humans who ate the beef.

But that is only the start. Chickens would normally lay only about 170 eggs per year. With clever feeding, suitable lighting, and other stimulation, they now average 240 eggs per year. The ambition is to increase this to 700 eggs per year by the addition of sex hormones to speed up the chicken’s egg-production cycle. They are fed dyes to make their yolks bright yellow, they are dusted with insecticides against parasites, and fed antibiotics to stop them from getting sick in the crowded conditions.

Since 1993, dairy cows have been injected with the hormone known as rBST to increase milk production by up to 25%. Antibiotics have routinely been added to animal feed since the 1950s to increase growth rate. All these measures are sanctioned by government authorities, chief among them the U.S. Food and Drug Administration (FDA). But even this is not enough for some: the competitive pressures to produce cheap meat are so great that unscrupulous cattlemen inject their herds with illegal substances, such as muscle-building steroids.

Mechanization

Meanwhile, in the 19th century, another major development was taking place—mechanization. Early steam “traction engines” were developed for plowing. These were cumbersome but were a great improvement on the horse-drawn methods. Soon, they were supplanted by the internal combustion engine in the form of tractors. The first successful gasoline tractor was built in the United States in 1892. The number of tractors increased dramatically in America from 600 in 1907 to almost 3,400,000 by 1950. Thus, mechanization was a tremendous force for increasing productivity and reducing the need for farm labor.

Through all these changes, the
nature
of the plants was changed by selective breeding. Combine harvesters, tomato reapers, or cotton pickers need plants that grow in specific ways to work efficiently, so the plants were bred to be more suitable for mechanical harvesting. In this way, mechanization drove a trend to change plants for convenient handling. Many plants do not lend themselves to mechanized production, so they were no longer farmed.

“
A chicken in every pot and a car in every garage”—that was the slogan used by Herbert Hoover in his 1928 presidential campaign. It is hard to imagine that, for the average American in those times, it was as rare to eat chicken as it was to own a car. Mechanization changed all that for both chickens and cars. Animals such as hogs and chickens could be kept in large sheds and reared in much more densely packed conditions. Their products became much cheaper. By the 1930s, farming had become so mechanized that this marked a major change: agriculture flipped from being a labor-intensive industry to one that used few farmhands but invested heavily in machines.

Plant Genetics

We have seen how ancient farmers selected the best plants for cultivation. This was a continuous process down through the centuries. Indeed, many plants that we know today are unrecognizably different from their wild ancestors. However, the process accelerated as commercial pressures of farming intensified. There have been some major successes. Millions more could be fed after the “green revolution” that occurred during the 1960s in Asian countries, when new, highly productive strains of rice were planted. However, often plants are modified for seemingly trivial reasons. Take, for example, wheat flakes: different varieties of wheat respond differently to milk. One of the major producers of breakfast cereal, General Mills, has a brand called “Wheaties.” They wanted a flake that curled on contact with milk and reduced sogginess in the breakfast bowl. General Mills undertook a development program to breed such a wheat and then contracted with farmers to supply only this variety.
³⁸
What happened to the nutritional quality? Perhaps nothing changed, but no one cared to find out either.