ANZHEN, China -- Nitrogen fertilizer has lifted the yoke off Hua Xijin's shoulders.
Before the "green revolution" came to China, it took roughly 6 tons of river mud to fertilize a rice paddy small enough to fit in the corner of a football field. Hua carried the mud on his back, 130 pounds at a time, in bamboo baskets lashed to a wooden pole.
Now 58-year-old Hua spends about a week each planting season sprinkling his field with hundreds of pounds of chemical fertilizer, leaving plenty of time for playing mah-jong or fishing in a nearby river.
Except there aren't any fish in the river anymore. Or turtles, prawns or water fit to drink.
Downstream from Hua's paddy is the mighty Yangtze, the third-longest river in the world and the last stronghold of an endangered sturgeon with a 50 million-year lineage. The Yangtze is so tainted with factory waste and fertilizer runoff from more than 300 million villagers' fields that it can't even come close to meeting relatively lax Chinese standards for industrial rivers.
And where the Yangtze meets the East China Sea, toxic red tides that can kill fish and poison people now sweep through the bay that provides one-fourth of China's seafood catch.
Once rare, the potentially lethal algae now bloom two to 10 times a year. Scientists think high levels of nitrogen-laden fertilizer and animal waste from farms fuel the outbreaks -- and the amount of those contaminants flowing into the Yangtze is expected to double in less than 15 years.
The Yangtze and bountiful Hangzhou Bay just south of its mouth are headed for ecological calamity if the Chinese government fails to bring chemical fertilizer use under control, a team of scientists warned in 1997. "Urgent attention is needed," concluded the study conducted by Delft Hydraulics, an international consortium.
This is the toxic fallout from the green revolution, which has led Asian farmers since the 1960s to rely heavily on nitrogen-based fertilizers to achieve badly needed increases in crop yields.
Meanwhile, Asian fishermen are also embracing aquaculture, the so-called "blue revolution," producing millions of tons of fish and shellfish in captivity -- along with highly concentrated streams of nitrogen from their waste.
China is the world's most striking illustration of man-made nitrogen's power to create and destroy. It has helped feed the world's most populous nation and eased lives of hardship unimaginable to most Westerners. But it is ruining the nation's rivers, bays and coastal waters.
And worse looms. In 20 years, experts say, Asia will be the dominant source of nitrogen pollution to Earth's air and water, producing more than all the rest of the world's nations combined and almost as much as all of the planet's natural processes.
The green and blue revolutions have already produced unintended, devastating consequences for waters all across Asia. Toxic algae outbreaks are becoming more frequent and the economic losses are mounting. In just the past year, red tides have devastated fishing grounds and fish farms in China, Thailand, Malaysia and Indonesia.
In places like South China's Zhelin Bay, fish farms are ravaged again and again. In the late 1970s, Li Zuohui saw his income skyrocket from less than $500 a year to about $25,000 because of fish farming. But today, the 47-year-old faces financial disaster each summer when red tides sweep through the bay, threatening to kill farmers' fish by the millions.
This summer, the coast south of Shanghai was blanketed with dead fish, shrimp, crabs and clams, all killed by the largest red tide ever recorded in China. At its height, the 2,700-square-mile bloom was big enough to cover Maryland's western shore from the Pennsylvania border south to Annapolis and west to the District of Columbia line.
It was among 20 to 30 red tides that Chinese experts forecast for this year. Over the past three years, the government says, large red tides have done $240 million in damage to China's economy. Officials explicitly blame nitrogen pollution -- but they continue to encourage Chinese farmers to pour on the fertilizer.
Unlike Europe and North America -- where chemical fertilizer use peaked in the 1980s and has since declined slightly or leveled off -- China's use has increased fivefold in the past 30 years and will double or triple again by 2020. In parts of China, farmers already use almost four times as much nitrogen fertilizer per acre as farmers in the American Midwest.
Now that peasants like Hua can afford to eat meat regularly, big Western-style livestock operations and the animal waste they produce are becoming a major new source of nitrogen pollution.
In the past two decades, China's recorded pig sales have soared. Pig and chicken farms within the vast area of central China drained by the Yangtze produce more than 40 times as much nitrogen pollution as all the region's factories -- and that is projected to increase sharply over the next decade.
Like most of Asia, China is in a bind: As its population of about 1.3 billion people grows, its available farmland is shrinking, throwing the nation into an urgent struggle to increase its farm productivity, says Chinese agronomist T. C. Tso, of the nonprofit Institute of International Development and Education in Agriculture and Life Sciences, in Beltsville.
But present-day farming techniques degrade both the soil and the water, making it tougher for the next generation to keep pace, experts say. "China does not now have a sustainable agriculture," Tso said at a February meeting of the American Academy for the Advancement of Science.
Mistakes of the West
Western scientists and some of their Chinese colleagues say Asia should not repeat the mistakes of the West. They say Asian farmers need to use fertilizer more wisely than Americans and Europeans have, retaining some traditional techniques and sacrificing short-term profits to leave fertile soil and healthy rivers for their children.
But for many Asians, such talk amounts to "Do as I say, not as I do," says Canadian ecologist Vaclav Smil of the University of Manitoba, an expert on Chinese food production.
The Chinese "degrade and pollute because of their rising numbers, because of their quest to lift themselves from bare subsistence and widespread poverty, because of their outdated techniques and poor management," says Smil. "We do the same thing, albeit in different ways, because of our excessive consumption and unnecessary waste."
Nevertheless, Smil and other experts agree that Chinese farmers' exclusive reliance on chemical fertilizer will eventually rob the land of its long-term productivity -- hastening erosion, weakening soil structure and leaching away essential minerals.
This is a major problem. As geographers Erle C. Ellis of the University of Maryland, Baltimore County and S. M. Wang of China's Nanjing Agricultural University have noted, even thousands of years ago, "the exhaustion of soil fertility by unsustainable farm management" was a big factor in the decline of major civilizations.
History offers only a handful of examples of farming practices sustained for generations that have not harmed the land and water. One of those is the 1,000-year-old rice- and wheat-growing culture that flourished along the Yangtze, where traditional methods of maintaining soil fertility have been replaced in just the past generation by the widespread use of chemical fertilizers.
Historians think rice was first domesticated along the Yangtze more than 8,000 years ago. And for more than 1,000 years, the farmers of the Yangtze's Tai Lake region, such as Hua Xijin and other Anzhen villagers, have been considered a model for the nation.
Tai Lake peasants created much of the region's rich farmland out of swamp, beginning in the 10th century. Through brutal labor and obsessive frugality with natural sources of nitrogen, they made their region "the granary of the empire" -- maintaining the land's fertility and the rivers' health.
Nothing went unused in paddies that were planted with rice in the spring, then drained after the harvest and planted in wheat and milk vetch, a legume that fertilizes the soil by capturing nitrogen from the air. Most households raised one or two pigs mainly for their nitrogen-rich manure, which was composted in tile-lined tanks along with human waste. The animals' straw was returned to the fields. Even silkworm wastes and cooking ashes were saved and used as fertilizer.
All that has changed.
Hua says it now takes just several hundred pounds of chemicals to get the effect he once got from tons of mud. He has gone from working in the fields 300 days a year to about 30 days. The rest of the time he spends with friends in his comfortable two-story home -- paid for by his son's job making packing foam at a nearby factory and his daughter-in-law's work at the local traffic administration.
Chemical fertilizers have almost tripled the crop yields of other Tai Lake peasants, says Cai Zucong, a leading Chinese soil scientist. That has allowed many to become part-time farmers and get better-paying factory jobs.
But this extraordinary change for farmers has been potentially calamitous for the streams flowing through their fields, and for the Yangtze River and Hangzhou Bay. Only about 30 percent of their fertilizer ends up in the crops, Cai says. "Eventually all fertilizer that is lost from the fields goes to the East China Sea."
Twenty years ago, the streams and canals crisscrossing Anzhen villagers' fields were filled with fish, prawns and turtles. The 9-foot-deep Jiuli River by Hua's fields was so clear you could see every detail of the bottom.
Today the river, which drains into the Yangtze, is brown and choked with tree limbs. Visibility is just a few inches; aquatic life was killed off long ago.
But most of the area's farmers see only fertilizer's significant benefits. "This generation could not imagine how exhausting and how tiring and how hard farming was," says Hua's neighbor, Chen Qisong, 58.
And Hua blames industry, not fertilizer use, for the river's deterioration. Referring to the nitrogen-laden water seeping from his fields: "I can't see it and I can't smell it, so how do I know it's polluted?"
Nonetheless, the nitrogen is there. With about 2 percent of the world's river water, the Yangtze now supplies 9 percent to 18 percent of the total riverborne nitrogen flow to the world's coasts. Most of it comes from farming and livestock production, according to the Delft study, which was commissioned by the Chinese government.
Fueled by nitrogen runoff, algae blooms consume practically all the oxygen in parts of the Yangtze delta, making it unfit for aquatic life. Oxygen levels are dangerously low in the entire area set aside as a sanctuary for the endangered Yangtze sturgeon.
In Hangzhou Bay, just south of the Yangtze delta, red tides are chronic. The bay's Zhoushan Islands, a chain of more than a thousand forest-cloaked islets with the rugged beauty of classical Chinese paintings, have a "virtually unrivaled potential" for tourism, according to the Delft study -- were it not for the toxic blooms that sweep through several times a year.
Scientists have identified five species of harmful algae in the bay, including one that kills fish and two that can be passed along to people in tainted shellfish, causing gastrointestinal illnesses or potentially fatal paralysis.
Worldwide, some toxic blooms are believed to be strictly natural in origin. For other algaes, like the Pfiesteria found in recent years in the Chesapeake Bay, there's strong evidence that nutrient overdoses encourage their growth.
Research on the Hangzhou Bay red tides is scanty. But the Delft study noted that the outbreaks seem to follow the plume of nitrogen-rich Yangtze River water as it mixes with water from the East China Sea.
Predicting "severe and possibly irreversible harm" in the next decade, the study's authors recommended in 1997 that the Chinese government quickly pass strict regulations limiting farmers' use of fertilizer. That hasn't happened, says Cai.
The reason is simple: In China, food translates to power.
Even though the country has a grain surplus now, many still recall the great famine of 1959-1961 when as many as 30 million Chinese died. Hunger has contributed to the fall of many a Chinese dynasty over the centuries, and the current regime's claim to legitimacy rests on its ability to provide a rising standard of living -- including abundant food.
Cai says government pressure to use more fertilizer recently has eased as officials have begun to realize how much pollution it's causing. But he adds: "The government is very worried about food security."
And in China these days, many are looking to the blue revolution to help provide that security.
Thanks to an array of aquaculture techniques, chemicals and specially bred stocks developed over the past 20 years, almost one-fourth of the world's fish and shellfish are now farm-raised.
But as many Chinese fishermen-turned-fish farmers are discovering to their dismay, captive fish are even more vulnerable to nitrogen pollution than their free-roaming relatives.
In Zhelin Bay across from Taiwan, fish farms have multiplied so rapidly with so few environmental controls that the fish appear to be poisoning themselves with their own wastes.
A generation ago, this area was picturesque but poor. Local fishermen such as Li earned $30 to $40 a month working on deep-sea fishing boats. Then came the Chinese economic reforms of the late 1970s and early 1980s, when the government started allowing small private businesses.
Li began raising grouper and other fish, and he soon was earning a fortune by rural Chinese standards. He built a new house and equipped it with such coveted amenities as ceiling fans and a TV set.
Soon everyone wanted in the game. Aquaculture looked easy compared with deep-sea fishing.
Today some 30,000 fish cages are crammed into the bay's shallow, murky waters -- nets that sink out of sight beneath makeshift rafts of planks and barrels. Atop each raft stands a tar-paper shack where fish farmers burn incense at family shrines, drink green tea from tiny porcelain cups and chop up bait fish to feed their more valuable farm-raised fish.
At feeding time the caged fish swirl like piranha in a frenzy, crashing into the nets and one another. Uneaten food mingles with excrement from fish and fish farmers alike, clouding the waters where children splash and dive.
In Zhelin Bay, the first red tides came in 1995 and 1996. Li lost more than $120,000 worth of fish. He borrowed money and started over.
Then in 1998, a red tide killed 90 percent of the bay's farmed fish at an estimated loss of $7 million. At the time, Qi Yuzao, a professor at Jinan University in Guangzhou, found that the water beneath the aquaculture rafts had 60 percent more nitrogen and twice as much phosphorus, another fertilizer-turned-pollutant, as other parts of the same bay.
Qi blames the sudden appearance of red tides on the farmed fishes' waste, the rotting detritus of their food and the crowded conditions in the bay. He thinks fewer farms and better aquaculture techniques could control the problem -- but his suggestions are mostly ignored.
"The fishermen want more money," Qi says, "so they build more cages."
Red tides swept through Zhelin Bay again in the summer of 1999. Li filled up his old wooden skiff with water, dumped his fish in it and ferried them to nets in deeper, cleaner water. He saved his fish, but he couldn't protect his profits. Back in the bay, he's now finding that his fish grow more slowly than they did when the water was cleaner -- and that hurts his bottom line.
"If we don't have a red tide for two years, we have some profit," Li says. Besides, he adds, "we have nothing else to do."
South from Zhelin Bay, densely populated and industrialized Hong Kong also has been hit by red tides regularly over the past decade. By the mid-1990s, its waters were experiencing as many as 25 outbreaks each year, some lethal.
In 1998, when a bloom threatened the Hong Kong fishing village of Ma Wan, more than 100 fish farmers used their sampans' outboard motors to literally turn back the tide -- halting the incoming flow of toxins and saving about two-thirds of their fish.
That year alone, Hong Kong aquaculturists lost an estimated $40 million worth of fish. The newly discovered microscopic killer -- Gyrodinium HK98--- was one of more than 50 varieties of toxic algae found worldwide in recent decades.
John Hodgkiss, a University of Hong Kong professor, says levels of nitrogen and phosphorus, which nourish the blooms, have risen nine- and tenfold in some Hong Kong waters since the 1970s.
In addition to pollution from the area's many fish farms, the city of high-rises and high finance dumps almost two-thirds of its sewage into the sea with little or no treatment. It also sits at the mouth of the Pearl River, used as an open sewer by China's heavily industrialized Guangdong Province, where many goods labeled "Made in China" are manufactured. By the mid-1990s, 1.4 billion tons of domestic sewage a year -- almost all of it untreated -- was sweeping down the Pearl toward Hong Kong.
Given that enormous discharge, Hong Kong is reluctant to spend billions of dollars to clean up its own effluent, local scientists acknowledge. "It would be madness for Hong Kong to spend that amount of money to clean up our waters without something being done about the Pearl River Delta," says Hodgkiss.
The devastation all along China's coast seems destined to get worse, posing a huge ecological and economic threat to the world's most populous nation.
Modernization of China's economy has triggered an exodus from the countryside to cities, and valuable farmland is being gobbled up by urban sprawl and industries, ratcheting up the pressure on the land. Already, China feeds itself with just a quarter-acre of arable land per person; the United States uses seven times as much.
And economists say Chinese farmers will have to do even more with even less as already severe water shortages worsen, farming on marginal land increases soil erosion, and chemical fertilizers reduce their land's natural fertility.
The easiest short-term solution: Pour on more fertilizer.
Chinese leaders recognize the problem, but they have few alternatives. And some Western powers are encouraging China to modernize its agriculture just as the United States and Europe did, while ignoring concerns about the likely effects of nutrient pollution.
The World Bank, for example, acknowledged in a 1997 report that nutrient pollution from fertilizer is fast becoming one of China's gravest environmental woes. But it hasn't funded any programs to address the problem directly. Instead, the bank and the International Monetary Fund are helping the Chinese find investors to build huge new fertilizer plants.
China might soon need an environmental revolution just as badly as it needed the green and blue revolutions. Signs of a grass-roots environmental consciousness are slowly emerging, and lately China's authoritarian government has been strikingly open about the problems.
Tang Xiyang, a pioneer in China's nascent environmental movement, believes there's hope -- if traditional farming practices were blended with certain new technologies and if the Chinese people were given much greater freedom.
"Some people say there are too many people and their needs are great, but I think ... you can find a new way to solve these problems," Tang says. "Many people who love nature ... would even sacrifice their lives to protect the environment."