Initially, much of the increased production of fertilizer went into grains such as wheat and rice that served as the foundation of a basic diet. But recently, with world economic growth at a brisk 5% 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, such as corn-based ethanol, put new pressure on grain supplies. These factors translated into rising demand and higher prices for fertilizer.
Manufacturers are scrambling to increase the supply. But these projects are expensive and time-consuming, and supplies are expected to remain tight for years.
Fertilizer is vitally important in Iowa, the US state, whose farmers grow more corn than any other state, and depend on fertilizer to greatly increase their 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 soya bean fields to get ready access to manure.
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, around 10% of his farm, and save him perhaps $50,000 (around Rs20 lakh) annually. “Every little bit helps,” he said.
Such strategy has severe limits—manure contains so little nitrogen that tonnes are required on each acre. That means farmers 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, compared with around $4 billion three years ago, and has prompted calls to reform the programme that India depends on to maintain its food supply.
Once new supplies become available, the rising use of fertilizer will still pose difficulties. Environmental groups fear increased use, particularly of nitrogen fertilizer made using fossil fuels. Because plants do not absorb all the nitrogen; much of it leaches into streams and groundwater. That run-off has long been recognized as a major pollution problem, and it is growing as food production increases.
A barometer of that pollution is the rising number of dead zones where rivers meet the sea. In the Gulf of Mexico, for instance, nitrogen run-off 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 run-off, said Robert J. Diaz, a professor at the Virginia Institute of Marine Science. “Nitrogen is nitrogen,” Diaz said. “If it’s on land, it produces corn. If it gets in the water, it produces algae.”
Earlier this month, a UN panel called for urgent changes in agricultural practices to make them less damaging. The panel recommended techniques that offer some of the same benefits as chemical fertilizer, such as increased crop rotation using soya beans and other legumes that naturally add some nitrogen to the soil.