The Food Chain

Shortages Threaten Farmers’ Key Tool: Fertilizer

Credit...Justin Mott for The New York Times


The biggest reason the children are so robust: fertilizer.












Credit...Justin Mott for The New York Times



Recently, Ms. Nha, the tiny Vietnamese woman, stood in a field outside her village, her weather-beaten face shielded from the drizzle by a big straw hat. She took a break from wielding her wood-handled hoe and described the meager diets of her youth.

Her family, including six brothers and sisters, struggled to survive on rations from the commune where they lived, eating little protein. The occasional pigs they raised on rice stalks and mush “fattened very slowly,” Ms. Nha recalled.

But with market reforms, better seeds and increased fertilizer use, Vietnam’s rice yields per acre have doubled and corn yields have tripled, allowing farmers to fatten a growing herd of livestock.

Several times a season, Ms. Nha and her neighbors walk down their rows of corn with battered metal buckets full of chemical fertilizer, which looks like coarse gray sand, sprinkling a bit at the base of each plant. Ms. Nha’s husband, Le Van Son, remembers villagers’ amazement in the 1990s when they learned that a pound of chemical fertilizer contained more of the major nutrients than 100 pounds of manure.


“Markets are asking farmers to step on the accelerator,” said Michael R. Rahm, vice president for market analysis and strategic planning at Mosaic, a fertilizer producer in Plymouth, Minn. “They’ve pressed on it, but the market has told them to step on it harder.”


That limitation ended in the early 20th century with the invention of a procedure, now primarily fueled by natural gas, that draws chemically inert nitrogen from the air and converts it into a usable form.

As the use of such fertilizer spread, it was accompanied by improved plant varieties and greater mechanization. From 1900 to 2000, worldwide food production jumped by 600 percent. Scientists said that increase was the fundamental reason world population was able to rise to about 6.7 billion today from 1.7 billion in 1900.


Initially, much of the increased production of fertilizer went to grains like wheat and rice that served as the foundation of a basic diet. But recently, with world economic growth at a brisk 5 percent a year, hundreds of millions of people began earning enough money to buy more meat from animals fattened with grains. That occurred at the same time that rising production of biofuels, like ethanol, put new pressure on grain supplies.

These factors translated into rising fertilizer demand. Prices at a terminal in Tampa, Fla., for one fertilizer, diammonium phosphate, jumped to $1,102 a ton from $393 a ton in the last year, according to JPMorgan Securities, which tracks the prices. Urea, a type of granular nitrogen fertilizer, jumped to $505 a ton from $273 a ton in the last year.


Fertilizer is vitally important in Iowa, whose farmers grow more corn than in any other state and depend on fertilizer to increase yields.

But the combination of high prices and spot shortages has forced some farmers to revert to older methods of fertilization, making hog manure a hot commodity. Farmers are cutting deals to have hog barns built on the edges of their corn and soybean fields.

On a tour of his rolling farm in Oxford Junction in eastern Iowa, Jayson Willimack pointed to the future sites of two buildings that will hold 2,400 hogs. Their manure will eventually replace commercial fertilizer on 400 acres, about 10 percent of his farm, and save him perhaps $50,000 annually. “Every little bit helps,” he said.

Such a strategy has severe limits  manure contains so little nitrogen that tons are required on each acre. That means farmers in Iowa and abroad have little choice but to pay the higher prices for commercial fertilizer.

In many countries, those cost increases have so far been offset by record high prices for crops. But fertilizer inflation has created a crisis in countries that subsidize fertilizer use for farmers. In India, for instance, the government’s subsidy bill could be as high as $22 billion in the coming year, up from $4 billion in 2004-5.

Once new supplies become available, the rising use of fertilizer will still pose difficulties.


A barometer of the pollution is the rising number of dead zones where rivers meet the sea. In the Gulf of Mexico, for instance, nitrogen runoff from fields in the Corn Belt washes downstream and feeds plant life in the gulf. The algae blooms suck oxygen from the water, killing other marine life.

More than 400 dead zones have been identified, from the coasts of China to the Chesapeake Bay, and the primary reason is agricultural runoff, said Robert J. Diaz, a professor at the Virginia Institute of Marine Science.

“Nitrogen is nitrogen,” Professor Diaz said. “If it’s on land, it produces corn. If it gets in the water, it produces algae.”

This month, a United Nations panel called for changes in agricultural practices to make them less damaging. The panel recommended techniques that offer some of the same benefits as chemical fertilizer, like increased crop rotation with legumes that naturally add some nitrogen to the soil.

But others say those approaches, while helpful, will be not be enough to meet the world’s rapidly rising demand for food and biofuel.
