Terminator Genes
Dust Bowl
Organic farming in Cuba
Regenerative farming in Iowa
Are Shrimp Safe to Eat?
Environmental Estrogens

Research in biotechnology and genetic engineering is very expensive. Monsanto is reported to have spent $500 million developing Roundup Ready genes, or about as much as the entire annual USDA research budget. Naturally, they want to protect potential profits from this valuable property. Farmers who buy Monsanto seeds are required to sign a contract that stipulates what kinds of pesticides can be used on fields as well as an agreement not to save seed or allow patented crops to cross with other varieties. Seed sleuths investigate to ensure that contracts are fulfilled. By inserting unique hidden sequences in their synthetic genes, forensic molecular biologists can detect the presence of patented genetic material in fields for which royalties weren't paid. Already Monsanto has taken legal action against more than 300 farmers for replanting proprietary seeds. Farmers claim they can't prevent transgenic pollen from blowing onto their fields and introducing genes against their will. A whole new set of legal precedents is likely to be established by these suits.

A new weapon has recently been introduced in this struggle that many people regard as quite sinister. Using genetic research of a USDA scientist, a small company called Delta and Pine Land developed genetic material officially entitled "gene protection technology" but commonly known as "terminator" genes. The terminator complex includes a toxic gene from a noncrop plant stitched together with two other bits of coding that keep the killer gene dormant until late in the crop's development, when the toxin affects only the forming seeds. Thus, although the crop yield is about normal, there is no subsequent generation and no worry about farmers saving and replanting. They have to buy new seed every year. Delta was quickly purchased by Monsanto for $1 billion, or hundreds of times the small company's book value. This may have been the only time a whole company was purchased just to get a gene complex.

Engineered sterility is not uncommon; it is widely used in producing hybrid crops such as maize. What is unusual about this gene-set is that it can be moved easily from one species to another, and it can be packaged in every seed sold by the parent company. It's also unique to deliberately introduce a toxin into the part that people eat. So what's wrong with a company trying to protect its research investment? For one thing, there's a worry that the toxins might be harmful to consumers, even though toxicity tests so far show no danger. Furthermore these genes may escape. What if some of our major crops become self-sterile and can no longer reproduce? A more immediate concern is the economic effects in developing countries. While seed saving is not common on farms in most developed countries, it is customary and economically necessary in many poorer parts of the world. Melvin Oliver, the principal inventor of the terminator genes, admits that "the technology primarily targets Second and Third World markets"-in effect, guaranteeing intellectual property rights even in countries where patent protection is weak or nonexistent.

Large corporations like Monsanto argue that without patent protection, they can't afford to do the research needed to provide further advances in biotechnology. Critics charge that these companies make enough profit in developed countries to pay back their costs. Targeting less-developed countries and introducing something as potentially dangerous as the terminator gene, they claim is immoral. International protests caused Monsanto to announce in 1999 that it was suspending plans to release crops with terminator genes "for the time being." Still, biotechnology research continues at a furious pace and other genetically-modified organisms are sure to be available soon. What do you think? Are those who protest this technology simply afraid of things that are new and unfamiliar, or are there legitimate reasons for concern? How can we assess risks in a novel and unknown technologies such as these?

Dust Bowl Days

Sunday, April 14, 1935, dawned bright and clear over the city of Amarillo in the Texas panhandle. That afternoon, however, a huge black cloud of dust appeared on the northern horizon and quickly swept across the treeless plains. The dust swirled past, thick as falling snow, as cars stalled in the streets and pedestrians bumped into each other, unable to see things a few feet away. Terrified families huddled together with wet towels over their faces and rags stuffed in cracks around windows and doors, but still the dust seeped in. Tiny dunes formed on windowsills and doorjams and even the food in the refrigerator was covered with dust. Is this the end of the world, they wondered. And where did all this dirt come from?

This storm became known as Black Sunday and inspired the term "dust bowl" to describe both the decade of the 1930s and the high plains area where it occurred. The heart of the dust bowl stretched from Texas to Manitoba but airborne dirt was often carried as far as the East Coast. Amarillo averaged nine serious dust storms per month from January to April - the main dust storm season -- between 1933 and 1938. In April 1934, it had "black blizzards" on twenty-three days. Homes, barns, tractors, and fields were buried under drifts up to 7 m (25 ft) high.

These dust storms were the worst human-caused environmental disaster the United States has ever experienced. The social, economic, and ecological costs were immense. The Soil Conservation Service, founded in 1935 to address this calamity, estimated that 40 billion tons of topsoil from the heart of the world?s breadbasket had blown away on the wind. By 1938, farm losses had reached $25 million per day and more than half the rural families on the Southern Plains were on relief. Thousands of people died of "dust pneumonia," while millions joined the mass migration described by John Steinbeck in The Grapes of Wrath (1939).

A prolonged drought beginning in 1931 was the immediate cause of the dust storms, but inappropriate agricultural practices allowed erosion to occur, exacerbating the situation. Early in the twentieth century, American farmers were caught up in a specialized, market-driven system that encouraged all-out production and drove out diversified, subsistence farming. During World War I, rising wheat prices, unusually wet weather, and availability of tractors and combines encouraged speculators to expand cultivation into previously untouched land. Without prairie sod to protect the soil, the land blew away when drought came back in the 1930s.

To combat wind erosion, the Soil Conservation Service sponsored research and demonstration projects in alternative farming methods. It also helped finance shelterbelts (rows of trees planted as windbreaks), strip-cropping, reestablishment of grass on damaged cropland, and new tillage methods. Although it will take centuries to rebuild topsoil, most of the visible signs of this terrible erosion have been erased and huge dust storms rarely occur now. Still, this historic example raises questions for current generations. Have we learned from our past mistakes? Are our agricultural policies and practices sustainable today?

The biggest experiment in low-input, sustainable agriculture in world history is occurring now in Cuba. The sudden collapse of the socialist bloc, upon which Cuba had been highly dependent for trade and aid, has forced an abrupt and difficult conversion from conventional agriculture to organic farming on a nationwide scale. Methods developed in Cuba could help other countries find ways to break their dependence on synthetic pesticides and fossil fuels.

Between the Cuban revolution in 1959 and the breakdown of trading relations with the Soviet Union in 1989, Cuba experienced rapid modernization, a high degree of social equity and welfare, and a strong dependence on external aid. Cuba's economy was supported during this period by the most modern agricultural system in Latin America. Farming techniques, levels of mechanization, and output often rivaled those in the United States. The main crop was sugarcane, almost all of which was grown on huge state farms and sold to the former Soviet Union at premium prices. More than half of all food eaten by Cubans came from abroad, as did most fertilizers, pesticides, fuel, and other farm inputs on which agricultural production depended.

Under the theory of comparative advantage, it seemed reasonable for Cuba to rely on international trade. With the collapse of the socialist bloc, however, Cuba's economy also fell apart. In 1990, wheat and grain imports decreased by half and other foodstuffs declined even more. At the same time, fertilizer, pesticide, and petroleum imports were down 60 to 80 percent. Farmers faced a dual challenge: how to produce twice as much food using half the normal inputs.

The crisis prompted a sudden turn to a new model of agriculture. Cuba was forced to adopt sustainable, organic farming practices based on indigenous, renewable resources. Typically, it takes three to five years for a farmer in the United States to make the change from conventional to organic farming profitable. Cuba, however, didn't have that long; it needed food immediately.

Cuba's agricultural system is based on a combination of old and new ideas. Broad community participation and use of local knowledge is essential. Scientific, adaptive management is another key. Diverse crops suitable to local microclimates, soil types, and human nutritional needs have been adopted. Natural, renewable energy sources such as wind, solar, and biomass fuels are being substituted for fossil fuels. Oxen and mules have replaced some 500,000 tractors idled by lack of fuel.

Soil management is vital for sustainable agriculture. Organic fertilizers substitute for synthetic chemicals. Livestock manure, green manure crops, composted municipal garbage, and industrial-scale cultivation of high-quality humus in earthworm farms all replenish soil fertility. In 1995 more than 100,000 metric tons of worm compost were produced and spread on fields.

Pests are suppressed by crop rotation and biological controls rather than chemical pesticides. For example, the parasitic fly (Lixophaga diatraeae) controls sugarcane borers; wasps in the genus Trichogramma feed on the eggs of grain weevils; while the predatory ant (Pheidole megacephala) attacks sweet potato weevils. Pest control also involves innovative use of biopesticides, such as Bacillis thuringiensis, that are poisonous or repellent to crop pests. Finally, integrated pest management includes careful monitoring of crops and measures to build populations of native beneficial organisms and to enhance the vigor and defenses of crop species.

Worker brigades from schools and factories help provide farm labor during harvest season. In addition to state farms and rural communes, urban gardening provides a much-needed supplement to city diets. Individual gardens are encouraged, but community or institutional gardens-schools, factories, and mass organizations-also produce large amounts of food.

Although food supplies in Cuba still are limited and diets are austere, the crisis wasn't as bad as many feared. In some ways, this draconian transition is fortunate. Cuba is now on a sustainable path and is a world leader in sustainable agriculture. It could serve as a model for others who surely will face a similar transition when our supplies of fossil fuels run out.

Dick and Sharon Thompson operate a diversified crop and livestock farm near Boone, Iowa. Originally, the Thompsons practiced high-intensity, monocrop farming using synthetic pesticides and fertilizers just as all their neighbors did. But they felt that something was wrong. Their hogs and cattle were sick. Fertilizer, pesticide, and petroleum prices were rising faster than crop prices. They began looking for a better way to farm. Through 30 years of careful experimentation and meticulous recordkeeping, they have developed a set of alternative farming techniques they call "regenerative agriculture" because it relies on natural processes to rebuild and protect soil.

Rather than depend on synthetic chemical herbicides and pesticides to keep their fields clean of weeds and pests, the Thompsons use a variety of old and new techniques including crop rotation, cover crops, and mechanical cultivation. Instead of growing corn and beans over and over again in the same fields as most of their neighbors do, the Thompsons change crops every year so that no one weed species can become dominant and all species remain relatively easy to control. In the fall, nitrogen-fixing cover crops are planted to hold soil against wind erosion and to keep down weeds.

Before planting, animal manure is spread on fields to rebuild fertility. During the summer, cattle are pastured on fallow land, using intensive grazing techniques that discourage weed growth and spread of manure over the whole field. The soil organic content-the sentinel indicator of soil health-registers at 6 percent, which is more than twice that of their neighbors. Untouched Midwestern prairie usually has about 7 percent organic content. The capacity to store extra carbon in soil might allow farmers to bid on carbon set-aside contracts.

The high levels of organic matter and available nutrients in the Thompsons' fields, coupled with the absence of pesticides that might harm beneficial microbes and pathogens, help crops compete against weeds and insects. Weed control specialists predict that in the future more farmers will follow the Thompsons' lead and concentrate on microbial biocontrol rather than depend on conventional herbicide-dependent systems, some of which can impair soil quality and lead to carryover injury to crops.

Among the cultivation techniques used by the Thompsons are chisel plowing, ridge-tilling, and rotary hoe cultivation. These techniques leave more crop residue on the surface to protect the soil than does conventional moldboard plowing. Chisel plowing merely scratches the surface rather than turning the soil upside down. The rotary hoe is a tool used just after crops germinate to skim the soil surface and remove recently germinated weeds. In ridge tilling, a small plow scrapes weeds out of shallow valleys and mounds up soil into small ridges where crops grow.

More is known about the Thompson operation-production methods, yields, costs and returns, weed counts, soil quality, and environmental impacts-than any other similar farm in the United States. Through 30 years of on-farm experiments, the Thompsons have collaborated with scientists from a variety of institutions. Dozens of research reports and articles have been written about how the Thompsons' diversified farming system affects land fertility, erosion, and livestock health. Every year a field day is held on the farm to give neighbors and others a chance to see how the diversified system works.

While yields on the Thompsons' land is comparable to those of their neighbors, lower reliance on off-farm inputs-including pesticides, fertilizers, and animal drugs-keeps the Thompsons' production costs significantly lower than those in conventional cropping systems. Growing corn costs the Thompsons $1.50 per bushel compared to $2.11 per bushel on neighboring farms. Similarly, soybeans cost the Thompsons $3.90 per bushel compared to $4.80 per bushel for their neighbors. In addition to favorable financial returns, the Thompsons benefit in other ways from their innovative system. The quality of their soil is significantly better than that under conventional agriculture and is steadily improving in fertility, tilth, and health.

Through their innovative work, Dick and Sharon Thompson are helping find ways to profitably produce high yields without degrading the land or the environment. In 1996, the Thompsons were selected by the Des Moines Register as Iowa's "Farm Leaders of the Year" in recognition of their contributions to the science of sustainable agriculture.

Are Shrimp Safe to Eat?

If you've bought shrimp recently at a restaurant or grocery store, chances are very good that they came from a commercial shrimp farm in a developing country such as Thailand, Ecuador, or Mexico. Once considered a luxury food, shrimp has become much more affordable in recent years, and now competes with tuna as the most popular seafood in the United States. As the world's leading shrimp-consuming country, the U.S. imports around 500,000 metric tons of farm-raised shrimp every year, or about half the total world production. Although this plentiful supply of a reasonably priced, highly desirable food is a boon to diners, there are social and environmental costs associated with its production that aren't widely known.

Shrimp aquaculture or farming first became profitable about 20 years ago and has since mushroomed into a major industry in the developing world. While total catches of wild shrimp have remained relatively stable at about 2 million metric tons per year over the past two decades, farm-raised production has exploded from less than 80,000 metric tons in 1980 to nearly one million metric tons in 1998. These shrimp are raised in shallow ponds ranging in size from a few hundred square meters to many hectares, generally constructed on or near the coastline of a tropical country. Asia has by far the largest area devoted to shrimp farming with more than 1.2 million hectares (3 million acres) in Thailand, Indonesia, China, India, Vietnam, and Bangladesh. Ecuador, with 130,000 hectares of ponds, raises about 60 percent of all shrimp in the Western Hemisphere, and is second in the world (after Thailand) in total production.

Hailed as a "blue revolution" 25 years ago, shrimp farming and other types of aquaculture were promoted as a way to provide a nutritious, inexpensive source of protein for the growing world population as well as to reduce the pressures on already dwindling supplies of wild seafood. While much commercial fish farming has been devoted to high-price, export species such as salmon, shrimp, and oysters, cultivation of some 10 million metric tons of less expensive freshwater fish such as carp and tilapia for local consumption has, indeed, increased the protein supply available in many developing countries. Culture of saltwater species such as shrimp, however, has caused considerable damage both to wild stocks and also to ecosystems that support them.

One of the biggest problems is that flooded mangrove forests and coastal wetlands often are destroyed to build shrimp ponds. Mangrove forests are extremely important as nurseries for a wide variety of ocean species. They absorb excess nutrients and sediment that would otherwise pollute nearshore waters and threaten coral reefs. About half of all mangrove forests in the world already have been destroyed. Shrimp farms are thought to be responsible for about one-fourth of that destruction. Furthermore, because shrimp farms often are stocked in very high densities, fresh seawater is flushed regularly through the ponds to wash out uneaten food, dead animals, feces, ammonia, phosphorus, and carbon dioxide. To prevent diseases among the teeming shrimp populations, most farmers also treat the ponds with antibiotics and chemicals such as formalin and calcium hypochlorite to kill pathogens and pests. All these wastes can leak into freshwater aquifers or overload coastal waters into which they are dumped, causing eutrophication and poisoning large numbers of resident organisms. Similar problems often occur in salmon-raising operations.

Most Asian shrimp farms are stocked with hatchery-produced young shrimp that can be certified free of diseases. In Latin America, however, many shrimp farmers prefer to stock their ponds with juvenile shrimp caught in the wild because they are cheaper and are thought to be stronger and have a higher survival rate. Shrimp harvesters scour estuaries and tidal wetlands to collect young shrimp to sell to farmers. Their fine-mesh nets catch large numbers of unwanted "by-catch" species. Although evidence is sparse, there are concerns that this harvest depletes populations of both wild shrimp and many other species. Furthermore, carnivorous species like salmon and shrimp often are fed high-protein fish meal made from wild ocean fish (sardines, anchovies, pilchard, and other low-value species). Because it takes roughly 2 kg of fish meal to produce a kilogram of farmed fish or shrimp, the result is a net loss of protein.

Not all aquaculture operations are environmentally harmful. With conscientious, scientific management, excess feeding can be minimized, diseases can be controlled without harmful chemical or antibiotic releases, water use can be minimized, and polluted effluent can be treated before being discharged into the environment. Rather than abandon contaminated ponds and start over building expensive new facilities on virgin land, farmers are learning to be careful in how they manage their operations. There isn't yet a certification process, however, so consumers can't tell whether the seafood products they buy have been obtained in an ecologically sound and sustainable manner.

So, while eating shrimp is probably safe for you, it may not be good for the environment. This example is only one of many dilemmas we face with respect to food and agriculture. In this chapter we will look at global food supplies and some of the problems associated with production and distribution of food.

Environmental Estrogens

What might alligators in Florida, seals in the North Sea, salmon in the Great Lakes, and you have in common? All are at the top of their respective food chains and all appear to be accumulating threatening levels of toxic environmental chemicals in their body tissues. One of the most frightening possible effects of those chemicals is that they seem to be able to disrupt endocrine hormones that regulate many important bodily functions. Evidence for this seems quite convincing in some wildlife populations, but whether it also is true for humans is one of the most contentious and important questions in environmental toxicology today.

One of the first examples of hormone-disrupting chemicals in the environment was a dramatic decline in alligators a decade ago in Florida's Lake Apopka. Surveys showed that 90 percent of the alligator eggs laid each year were infertile and that of the few that hatched, only about half survived more than two weeks. Male hatchlings had shrunken penises and unusually low levels of the male hormone testosterone. Female alligators, meanwhile, had highly elevated estrogen levels and abnormal ovaries. The explanation seems to be that a DDT spill in the lake in the 1980s, along with pesticide-laden runoff from adjacent farm fields, has led to high levels of DDE (a persistent breakdown product of DDT) in the reptiles' tissues and eggs. Because of a similarity in chemical structure, DDE appears to interfere with the action of androgens and estrogens, the normal sex hormones.

Researchers have begun to suspect that mysterious outbreaks of health and reproductive problems in other wildlife populations may have similar origins. Immune-system failures that killed thousands of seals along the coast of Europe and Scandinavia in 1992, for instance, are thought to have been caused by high levels of pesticides, PCBs, dioxins, and other toxins in their diet. Similarly, reproductive failures in fish and bird populations in the Great Lakes, fewer turtle hatchlings in farm ponds, abnormal thyroids and dramatic increases in tumors in fish, all are now thought to be related to hormone disturbances by exogenous chemicals.

But are humans affected as well? It is quite clear that people everywhere in the world have accumulated many of these same toxic chemicals in their bodies. Women who eat lots of fish from contaminated waters have been shown to have babies with elevated rates of mental, developmental, and behavioral disorders. Studies of women with estrogen-sensitive breast and vaginal cancers were found to have higher than normal levels of pesticides such as DDE in their tissues. Sperm counts in men appear to have decreased by about 50 percent over the past fifty years, while testicular and prostate cancers have increased dramatically during that same time.

Good evidence exists from controlled laboratory experiments that rats and mice exposed in utero or through mother's milk to very low levels of estrogen-like compounds develop physical, reproductive, and behavioral problems. We know that some of these chemicals act as synthetic hormones, others are antagonists that block normal hormone function. Furthermore, there can be striking synergy between some compounds. When endosulfan and DDT or chlordane are applied together, for example, the combination is 1600 times more estrogenic than either chemical alone.

The question is whether these chemicals are linked to human health problems. Many of these compounds are hundreds or thousands of times less active than normal hormones, leading skeptics to doubt that they have any noticeable effects except in animals exposed to extremely high levels from a chemical spill. Since some effects are positive while others are negative, they could cancel each other out. Furthermore, we may have protective mechanisms that are lacking in highly inbred laboratory rodents, and we can eat a highly varied diet that includes protective factors as well as toxins.

The bottom line is that we don't know (and we may never know for sure) whether falling sperm counts, increasing cancers, birth defects, immune diseases, and behavioral disorders in humans are caused by endocrine-disrupting environmental chemicals. Of course, we should do more research and testing of the physiological actions of these chemicals. In 1996, the EPA ordered pesticide manufacturers to begin testing for disrupting effects. Given the continuing uncertainty about the dangers we face, what more do you think we should do? Is this threat serious enough to warrant drastic steps to reduce our risk? If you were head of the Environmental Protection Agency or the Food and Drug Administration, how much certainty would you demand before acting to protect our environment and ourselves from this frightening potential threat?