“It’s a very basic and direct arithmetic point that putting fertilizer on the ground on a 1-acre plot can, in typical cases, raise an extra tonne of output,” said Jeffrey D. Sachs, the Col-umbia University economist who has focused on eradicating poverty. “That’s the difference between life and death.” The demand for fertilizer has been driven by a confluence of events, including population growth, shrinking world grain stocks and the appetite for corn and palm oil used to make biofuel. But experts say the biggest factor has been the growing demand for food, especially meat, in the developing world.
Recently, 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”, Nha recalled.
But market reforms in Vietnam during the last two decades gave farmers access to fertilizer and higher-yielding seeds. Rice yields for each acre have doubled and corn yields have tripled.
Several times a season, Nha and her neighbours walk down their rows of corn with battered metal buckets full of chemical fertilizer, which looks like coarse grey sand. They sprinkle a bit at the base of each plant and carefully hoe it in. Nha’s husband, Le Van Son, remembers villagers’ amazement in the 1990s when they learnt that a pound (0.45kg) of chemical fertilizer contained more of the major nutrients than 100 pounds of manure.
Overall global consumption of fertilizer increased by an estimated 31% from 1996 to 2008, driven by a 56% increase in developing countries, according to the International Fertilizer Industry Association.
“Markets are asking farmers to step on the accelerator,” said Michael R. Rahm, vice-president for market analysis and strategic planning at Mosaic, a major fertilizer producer based in Plymouth, Minnesota. “They’ve pressed on it, but the market has told them to step on it harder.”
Fertilizer is basically a combination of nutrients added to soil to help plants grow. The three most important are nitrogen, phosphorus and potassium. The latter two have been available for centuries, and today originate from mines. But nitrogen in a form that plants could absorb was scarce, and the lack of nitrogen led to low crop yields for centuries.
That limitation ended in the early 20th century with the invention of a procedure, now primarily fuelled by natural gas, that draws chemically inert nitrogen from the air and converts it into a usable form.
As the use of chemical nitrogen fertilizer spread, it was accompanied by improved plant varieties and greater mechanization. From 1900 to 2000, worldwide food production jumped by 600%. Scientists said that increase was the fundamental reason world population was able to rise to around 6.7 billion today, from 1.7 billion in 1900.
Vaclav Smil, a professor at the University of Manitoba, calculates that without nitrogen fertilizer, there would be insufficient food for 40% of the world’s population, at least based on today’s diets. Other experts have come up with slightly lower numbers.