Organic farming in Cuba
Regenerative farming in Iowa
Are Shrimp Safe to Eat?
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?
Organic Farming In Cuba
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
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.
Regenerative Agriculture In Iowa
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
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
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.
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?