Nitrogen fertilizer is seen by scientists today as a major contributor to global pollution problems. The history of nitrogen fertilizer is intertwined with the history of chemical warfare and the progressive destruction of the earth's topsoil. In the beginning of its history, fertilizer was thought to be the solution to the need to increase food production.
German chemist Fritz Haber won the 1918 Nobel Peace Prize for discovering the process of turning the nitrogen in the atmosphere into material that can be used to make fertilizer. He had discovered a way of tapping into the earth's reservoir of nitrogen gas and converting it into liquid ammonia. Liquid ammonia is the raw material for making fertilizer. He also invented chemical warfare and directed the release of 150 tons of chlorine onto British and French soldiers in Flanders in 1915, the first gas attack in military history.
Nitrogen is an essential element to all physical life on earth. It is a necessary ingredient in creating plant and animal proteins. The invention of nitrogen fertilizer provided a way to artificially stimulate crop production. Nitrogen fertilizer factories now produce 100 million tons a year and two billion people depend on it for their food production. Scientists now refer to this as a "nutrient overload" that is dangerous to life on earth.
Excessive amounts of nitrogen unbalance the physical cycle of growth and reproduction. Natural biological systems can absorb a certain amount of excess nitrogen but not the amounts produced today by nitrogen fertilizer use. Nitrogen saturation in the soil leads to loss of other nutrients such as calcium, potassium and magnesium. Grey, lifeless "dead soil" is the result. The science of agricultural sustainability seeks to reverse this trend.
"Nitrogen has a role in almost every environmental issue we have today," says James Galloway of the University of Virginia's Department of Environmental Sciences. Excessive nitrates pollute drinking water, produce smog and haze, and destroy the ozone layer. Nitrogen fertilizer goes from farmland to river to ocean, where it causes the excessive growth of algae. An overabundance of algae steals oxygen from fish and ocean plant life, causing "dead zones" where nothing else grows or lives.
The World Resources Institute says that "Reducing the risks of fertilizer use will require a combination of better agricultural practices that raise fertilizer efficiency and increased efforts to trap agricultural runoff before it leaches into waterways." The global effort towards sustainable agricultural practices works to raise awareness of farming practices such as composting and integrated pest management that reduce dependence on nitrogen fertilizers.