Technology & Medicine › Electric age
Haber–Bosch nitrogen fertilizer
1909 (Haber); industrial 1913 (Bosch)· Invention or discovery· Tools, energy & materials
Well documentedSolid records, physical evidence or scientific consensus.
An industrial process that pulls nitrogen from the air to make ammonia, the base of the synthetic fertilizer that now helps feed billions.
See it on the Technology & Medicine map →How it works
Plants need nitrogen, and air is 78% nitrogen, but in a form plants cannot use. Before 1913 farmers relied on manure and mined Chilean saltpeter (nitrate). In 1909 Fritz Haber combined nitrogen and hydrogen into ammonia using high pressure, heat and a catalyst. Carl Bosch of the chemical maker BASF scaled it up; the first plant opened at Oppau, Germany, in 1913. In World War I the same ammonia made German explosives, and Haber led Germany's poison-gas program.
Why it mattered
By most estimates, food grown with synthetic fertilizer sustains about half of humanity. The process also uses about 1–2% of world energy, and fertilizer runoff pollutes rivers and coasts.
How we know
Haber's 1909 patents and lab records; BASF records of the Oppau plant; Nobel Prizes to Haber (1918) and Bosch (1931); fertilizer and crop statistics analyzed by Vaclav Smil and others.
Still unknown or debated
Estimates of how many people depend on it range from about 40% to 50% of humanity; Haber's double legacy, fertilizer that feeds and gas that killed, is still argued over.
Inside this (1)
Connections (2)
▸Haber–Bosch nitrogen fertilizer was the fertilizer behind the Green Revolution (Borlaug)Well documented
The connection
The new short wheat and rice gave big yields only with heavy nitrogen fertilizer, which Haber–Bosch factories made cheap. Older, taller varieties fell over when fertilized that heavily. Fertilizer use in developing countries rose many times over between the 1960s and 1980s.
When and how
Fertilizer plants built rapidly worldwide after 1945; Mexico from the 1950s; India and Pakistan from 1965–66.
How we know
Field trials showed the new varieties' yields depended on fertilizer; FAO statistics show fertilizer use and grain yields rising together.
Debates and open questions
Fertilizer runoff pollutes water and creates oxygen-starved 'dead zones' in seas; how much nitrogen farming can sustainably use is a live debate.
▸Haber–Bosch nitrogen fertilizer transformed Agriculture (the Neolithic Revolution)Well documented
The connection
Crops need nitrogen, and natural sources such as manure, guano and mined nitrates were limited. Fritz Haber showed in 1909 how to make ammonia from nitrogen in the air plus hydrogen; Carl Bosch scaled it up at BASF by 1913. Synthetic fertilizer greatly raised crop yields and now feeds, by common estimates, about half of humanity.
When and how
Germany: Haber at Karlsruhe, 1909; Bosch's industrial plant at Oppau, 1913; worldwide spread after 1950.
How we know
Fertilizer use and crop yields rose together after 1950; Jan Willem Erisman and colleagues (2008) estimated about 48 percent of people depend on it.
Debates and open questions
The exact dependence is an estimate; nitrogen runoff causes water pollution and dead zones, and how to grow enough food with less is debated.