Seeds of solution to nitrogen glut


To cut back on the flow of lethal nitrogen pollution to the world's waters, Iowa corn grower Roy Bardole would need to let go of the idea that the best farmer is the one with the biggest crop. He'd have to use less fertilizer or set aside some land as a natural pollution filter -- yet still earn enough to support four generations on his 1,000 acres.

Chinese fish farmer Li Zuohui would have to surrender some of the quick profits that have transformed his life. He'd have to thin out the cramped, cloudy pens where he raises grouper by the thousands and spend a big chunk of his income on nonpolluting fish food, instead of on Western-style appliances and other talismans of the good life.

And millions of Americans would have to give up some of their favorite things, too, trading in their sport utility vehicles for less-polluting cars and cutting back on steaks in favor of beans, greens and grains.

There is no one source, and no one solution, for the worldwide glut of nitrogen that is overdosing Earth's living things with twice as much fertilizer as nature intended.

And it isn't a problem that will resolve itself without action. Population growth and prosperity are on track to send nitrogen pollution soaring, especially in Asia.

The United Nations projects that -- with world population increasing by almost 50 percent in the next 50 years and with the growing worldwide preference for a North American-style meat-based diet -- the world's farmers will have to grow twice as much grain as they do now.

University of Minnesota ecologist David Tilman estimates that to double global food production would take almost three times as much nitrogen fertilizer as the world is using now.

Add other expanding sources, such as the burning of oil, coal and gas and the planting of crops that capture nitrogen from the air, and Earth will be absorbing roughly four times as much as nature intended, Tilman estimates.

The mounting problems could be brought under control with a combination of techniques. But it would take a worldwide commitment -- and the nations of the world are far from unified.

In Europe, where the unintended consequences of nitrogen excess are obvious, many governments acknowledged the problem years ago and are trying, with limited success, to impose solutions.

In the United States, by contrast, nitrogen's damage to the Chesapeake Bay might worry Marylanders, and Louisianians might fear for the future of the Gulf of Mexico, but the rest of the country doesn't see many effects of nitrogen pollution. So there's no consensus on taking action.

And such developing countries as China simply have more pressing priorities. The Chinese government knows the nation's fisheries are at risk from excess nutrients. But the need to feed its people and industrialize takes precedence.

The split among nations on this issue is not so different from the international debate over global warming, a debate in which developing nations have long been suspicious of their more prosperous neighbors' push for environmental controls.

Most experts who have pondered the nitrogen dilemma believe it's unlikely that governments, big businesses and ordinary folks would join forces around the globe to halt the spread of nitrogen pollution.

"It's like global warming. You're probably never going to be able to say with absolute certainty, 'This is the bottom line,' " says Dennis Keeney, former director of the University of Iowa's Leopold Center for Sustainable Agriculture. "It's hard to convince people that the impact several hundred miles away is important. Maybe someday that will happen, but I doubt it."

But unexpected events -- such as the toxic Pfiesteria outbreak that hit the Chesapeake Bay in 1997 -- can sometimes change people's minds in a hurry.

Ten years ago, it seemed downright impossible that Maryland poultry growers would team up with a maverick agricultural researcher, Russ Brinsfield, in a quest to cut the flow of nitrogen into the Chesapeake Bay. In the mid-1980s, the University of Maryland scientist earned the industry's ire by insisting that nitrogen in fertilizer and chicken manure was polluting the bay. He urged farmers to try a simple technique for controlling the contamination.

Then came frightening outbreaks of the toxic algae, Pfiesteria, that seem to be fueled by the excess nutrients in agricultural runoff. The scary microorganism has killed fish, made people sick and threatened to knock the bottom out of two important Maryland industries: seafood and tourism.

And today, Brinsfield heads the Delmarva Poultry Industry's research advisory committee and is director of the nonprofit Maryland Agro-Ecology Center. "I only wish we had listened to Russ 10 years ago," says Jerry Truitt, a retired poultry association official.

Home-grown research

Brinsfield's background is atypical, an agricultural researcher who trained among cutting-edge marine biologists. That's the kind of flexible thinking that the nitrogen problem demands -- along with expertise in everything from crop genetics to fisheries, atmospheric chemistry, economics and politics.

The son of an Eastern Shore dairy farmer, Brinsfield was a graduate student at Indiana's Purdue University when his father died and he returned to Dorchester County to run the farm. He continued his studies at the University of Maryland's nearby laboratory at Horn Point, working among marine scientists who were trying to figure out why bay grasses were dying.

About 1980, Ken Staver, a young researcher there, noticed something his professors had missed: The grasses were covered with a green slime thick enough to block the light they needed. The experts, who had never seen healthy bay grasses, assumed they were supposed to be that way. But it turned out that nitrogen and phosphorus running into the bay were feeding the slime.

Science suggested that farm runoff and sewage discharge were the main culprits, but farmers and their political allies steadfastly denied their role. J. Court Stevenson, a Horn Point ecologist, remembers that a university official told him in the 1970s: "If you want to have a career in Maryland, don't mention agriculture and pollution in the same talk."

Brinsfield ignored that advice. Beginning in 1984, he and Staver documented the movement of large amounts of nitrogen from farmland into the bay. Traditional control methods were virtually no help, they found. "Agriculture's approach was honorable and well-intentioned, but it just wasn't doing the job," Brinsfield says.

Brinsfield remembered his father's habit of planting winter crops to feed the cows and control erosion. Recalling the bright green color, he realized the crop was pulling nitrogen from the soil. He and Staver proved that certain winter crops, grown with no additional fertilizer, could absorb 40 percent or more of the excess nitrogen in farm fields -- nitrogen that otherwise would be washed into the bay by winter rains.

Today, the state subsidizes the planting of cover crops, but they are used on only a small fraction of Maryland's half-million acres of farmland draining into the bay. They're even more rare in the farm belt states that contribute to the Gulf of Mexico's dead zone, North America's largest area of nitrogen-contaminated waters.

The reason: money. Planting cover crops typically costs farmers at least $20 an acre -- an expense they cannot pass on by boosting grain prices, which are near record lows.

"This is the first time we've asked farmers to do things that cost them money," says Brinsfield. The price is so high, and the benefits to the rest of society are so great, that "society has to subsidize it. But so far, we don't have the will. Everybody likes cheap food."

To cut fertilizer use without costing farmers money, Stanford University ecologist Pamela Matson and economist Rosamond Naylor have been working with wheat farmers in Mexico's Yaqui Valley, the birthplace of the "green revolution."

Heavy fertilization has sharply boosted crop yields there but, as elsewhere, much of the value of the fertilizer leaks away.

By carefully timing fertilizer use, Matson and Naylor found, farmers can cut nitrogen losses by a third and save $20 an acre or more, while keeping yields steady. "It's essentially substituting knowledge and management for fertilizer," Naylor says.

In Maryland, some farmers have begun using tractors equipped with computers linked to satellite technology to micromanage fertilizer use, applying only as much as each patch of land needs.

But Iowa farmer Bardole, who cut back his fertilizer use and would like to do more, says he hasn't found a reliable method yet. "The technology isn't there," he says.

Fertilizer insurance

Not far from Bardole's farm, along the banks of Iowa's Bear Creek, scientists have found an easy way to reduce nitrogen runoff into rivers and streams and ultimately the Gulf of Mexico: They can simply leave a narrow strip of nitrogen-absorbing trees and shrubs along ditches and streams.

But the buffer strips slightly reduce the amount of land devoted to crops, and that reduction "can make the difference between bankruptcy and luxury," says Iowa State ecologist John Downing.

To protect farmers against losses if they conserve fertilizer and lose money as a result, the Iowa Farm Bureau also is teaming up with the National Soil Tilth Laboratory in Ames to develop a fertilizer insurance program. The idea: Farmers who use less fertilizer would buy insurance policies that would pay off if their yields went down.

About 15 percent of Iowa's farmers are voluntarily cutting fertilizer use, recognizing that it's good for the environment and the bottom line. "But farmers have been programmed since the 1930s that the government will reimburse them, pay them to do things," say Larry Thomsen of West Central Co-op in Ralston, Iowa, "and until that happens, you won't see much of an effect."

Thomsen's main job is to sell farmers fertilizer. Nevertheless, he's leading an effort to cut fertilizer use in central Iowa. He's had some success but says, "The only way I see it happening is with mandatory regulation."

In Maryland, state limits on fertilizer use are scheduled to take effect beginning in 2003. Other states also have taken steps in recent years to control farm pollution -- the latest being Virginia. This week it adopted its first environmental regulations for poultry farming, which call for tracking what happens to the birds' manure.

But state officials say that fairness calls for nationwide regulations, and there's no such legislation pending in Congress.

In October, a federal task force is to recommend ways to cut the flow of nitrogen pollution to the Gulf of Mexico. Task force participants have said it will set goals for voluntary nitrogen reductions from Midwestern farm fields, but will not suggest that the EPA impose new regulations. Some farm state officials, including Iowa's agriculture secretary, object strenuously to even voluntary goals.

European countries have been wrestling with the nitrogen pollution problem for about two decades longer than the United States, and they have a variety of regulations. But the European Union has begun legal proceedings against nine countries for "significant lack of progress in reducing nitrogen." And that includes the Dutch, whose tough policies must cope with the world's highest concentrations of manure from livestock.

Though not among the nine nations under EU pressure, the Swedes are especially concerned about the impact on their fisheries and scenic coastline, and the Swedish government has arguably done as much as any to rein in farmers' fertilizer overflow. Fertilizer there is taxed at 30 percent to encourage its efficient use. Organic farming, which uses no commercial fertilizer, is subsidized. And to limit nitrogen-rich manure, Sweden limits the number of animals on farms.

But it has not been nearly enough.

In the mid-1980s, Sweden set a goal of reducing nitrogen levels 50 percent by 1995; that deadline has been moved back to 2005 and probably still won't be met. Without fundamental change in modern farming methods, reducing nitrogen levels by any more than 25 percent "may not be a realistic goal," says Arne Gustafson, a Swedish agricultural researcher.

Meat boom

Adding to the dilemma, a boom in meat production -- combined with the spread of modern methods for raising livestock in huge enclosed barns -- makes it much harder to safely handle animal waste.

Worldwide, animal manure has outstripped human waste as a major source of water pollution. In the United States, animals produce 130 times more waste than people do -- about 5 tons per person a year, according to a 1997 U.S. Senate study.

Livestock used to be raised on family farms in relatively small numbers, fed on locally grown grain, and their manure was spread on nearby fields.

Today, U.S. farmers produce the same number of hogs as they did 15 years ago, but on one-quarter the number of farms. Enclosed barns containing 30,000 hogs or more -- and their waste -- are becoming commonplace. The same is true of poultry- and cattle-raising, and the intensive techniques are spreading around the world.

The vagaries of the global meat market can leave toxic time bombs behind.

When Russia's economic woes helped trigger a plunge in pork prices in 1998, hundreds of North Carolina's giant hog farms went out of business, leaving behind open-air lagoons full of millions of gallons of hog waste. Last year in the wake of Hurricane Floyd's floods, several dozen lagoons spewed nitrogen-laden manure into waterways flowing into the vulnerable Pamlico estuary, the nation's second-most-productive commercial fishing area.

A recent North Carolina state survey found more than 1,000 abandoned hog waste pits, some of them chronically leaking. Cleanup costs are estimated at $30 million.

If the world's booming population will require more and more food, meat production is an inherently wasteful way to meet that need, says Norwegian agricultural researcher Marina A. Bleken. It takes 3 grams of nitrogen fertilizer to produce a gram of wheat flour, Bleken says, and 16 grams to make a gram of meat.

If everyone in the world ate like Americans of the 1990s, getting more protein from meat than their bodies need, it would take 120 pounds of nitrogen a year to feed each person, Bleken estimates. But if people ate a diet like Italians of the 1960s, richer in vegetables and grains than in meat, it would take about 70 pounds of nitrogen per person to feed the world.

"It is clear that a reduction of animal food in the diet would be the most effective way" of reducing agriculture's nitrogen use, says Bleken. But with grain prices basically unchanged for decades, many farmers rely on extra income from meat as a way to make ends meet.

And the worldwide trend is "clearly toward a more carnivorous diet as countries get richer and more industrialized," she says.

In China, for example, rising demand for meat, milk and farm-raised fish has nearly doubled protein and more than tripled fat in the average Chinese diet, according to Changhua Wu, head of China studies for the World Resources Institute. It's no coincidence that China now uses three times the world average of fertilizer per acre, and Chinese scientists suspect high levels of nitrogen runoff are to blame for an epidemic of red tides in the country's coastal waters.

Bleken says concerned scientists, economists and others from developed nations often ask her, "How can we stop developing countries from eating more meat?" Only by changing our own habits, she replies. "The standard we choose in Europe and North America influences the whole world."

Airborne damage

Second only to farming's impact is excess nitrogen released into the air from burning coal, oil and gas. Once aloft, the chemical rains on forests, prairies and bays that evolved over millions of years to flourish at much lower levels of fertilizer.

Airborne nitrogen accounts for only one-fifth of the total amount that humans set loose in nature. But because it travels so far and changes chemical form so easily, scientists think it could have disproportionately large effects. It accounts for a third of the excess nitrogen in Chesapeake waters.

Some landscapes are especially hard-hit. Even in a remote Minnesota nature preserve, nitrogen blowing in from other places has caused rare prairie plants to disappear, plant ecologist Tilman has discovered.

The U.S. Clean Air Act restricts nitrogen, but not enough to prevent damage to waterways, says Robert Howarth, a top nitrogen expert who directs ocean programs for the conservation group Environmental Defense.

Laws haven't done much to control nitrogen from sewage, either. With roughly half the world's population within 100 miles of coastlines, sewage concentrates large amounts of nitrogen in vulnerable waterways.

The World Health Organization estimates that 90 percent of the world's sewage is simply dumped untreated into rivers and oceans. Cities from Jakarta, Indonesia, to Key West, Fla., dispose of it this way. And with more meat in human diets, the nitrogen in sewage has gone up "substantially," says Canadian ecologist Vaclav Smil.

Even where sewage is treated, most processes don't do much to reduce nitrogen.

A treatment system called biological nutrient removal, pioneered in the Chesapeake Bay region, uses microbes to extract the bulk of nitrogen from sewage, but it isn't widely used.

And a new generation of "smart septic tanks" sharply reduces nitrogen seepage -- but this spring the Maryland General Assembly killed Gov. Parris N. Glendening's proposal to require extensive use of this state-of-the-art technology, claiming it was expensive and inconvenient.

Unplanned experiment

One vast unplanned experiment has proven that coastal waters can begin recovering if the nitrogen overload ends. It happened in the Black Sea, in the world's biggest, worst and most persistent dead zone.

The nearly landlocked sea was once considered Russia's Riviera, famed for its resorts and rich fisheries. For thousands of years, it has had a large, naturally occurring dead zone.

But from the 1960s to the 1980s, the Danube River became a pollution pipeline from Eastern Europe, carrying five to six times as much nitrogen as in the past. Other pollutants, including phosphorus, also skyrocketed. The result was a new 5,000-square-mile dead zone that devastated tourism and fishing.

Then came the collapse of the Soviet Union and of the economies of the Eastern bloc. Nitrogen pollution in the Danube fell to half its peak levels. By the late 1990s, oceanographers found scarcely a trace of the Black Sea dead zone, according to scientist Laurence D. Mee of Britain's Plymouth University.

Economic catastrophe hasn't cured the Black Sea -- merely granted it a "reprieve," says Mee. Its fisheries "remain devastated," he says, and an economic rebound could wipe out all environmental gains unless upstream nations enact better pollution controls.

Nonetheless, the Black Sea's rebound "shows reducing nitrogen will work," says Donald Boesch, a Chesapeake Bay expert and director of the University of Maryland's environmental research programs.

Ethical challenge

Meanwhile, scientists are tinkering with a vast array of methods for controlling nitrogen.

In New Mexico, researchers are trying to use vinegar to purify nitrogen-tainted well water. A Colorado group is trying to do the same thing with vegetable oil. In Iraq, tainted fertilizer factory wastes are being treated with molasses. And in Maine, they're trying beds of tree bark to filter the nitrogen-rich water left over after dairy farmers have hosed down their milking barns.

So far, the general public has paid little attention to the issue of excess nitrogen. But experts in science and government say that is bound to change as people realize nitrogen has become the world's most widespread water pollutant.

Tilman, the prairie plant ecologist, is one of those who've given the problem a lot of thought. He believes that some combination of scientific fixes, new laws and economic changes might eventually, over the next several decades, bring runaway nitrogen under control.

But more basic changes have to happen first, he told a February meeting of the American Association for the Advancement of Science.

"The green revolution brought the 35 most glorious years ever on the globe for agricultural production," Tilman said. "We're assuming we can continue ... if we just add more and more nitrogen. But I think we're facing a major problem."

In effect, he said, humans have altered evolution, "and we've done this inadvertently. We've done this without forethought. ... We really have to have major advances in ethics that relate to our impacts on the globe."

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