Urea (CO(NH₂)₂), a white crystalline substance containing 46% nitrogen, now supports nearly half of global food production. How did this accidental laboratory discovery in the 19th century become the indispensable “food for food” of modern agriculture?
I. Scientific Nature and Fertilizer Value
Urea was the first organic compound synthesized from inorganic materials, accidentally discovered by German chemist Friedrich Wöhler in 1828. In agriculture, its unique properties make it an ideal nitrogen source:
- 46% nitrogen content – 1.3 times that of ammonium nitrate, 2.2 times ammonium sulfate
- Excellent water solubility for easy plant uptake
- Low production cost at ~28-32GJ energy per ton
| Nitrogen Fertilizer | N Content(%) | Production Cost($/ton) | Global Share(2024) |
| Urea | 46 | 250-350 | 57% |
| Ammonium nitrate | 34 | 300-400 | 23% |
| Ammonium sulfate | 21 | 200-300 | 12% |
II. The Industrial Revolution That Changed Agriculture
In early 20th century, the Haber-Bosch process developed by German chemists Fritz Haber and Carl Bosch enabled mass production of urea. This breakthrough:
- Enabled 400% increase in global food production during 20th century
- Supported population growth from 1.6B (1900) to 8B (2023)
- Was hailed as “making bread from air” technology
“Modern urea plants can produce 3,500 tons/day – a single mid-sized facility’s annual output can meet the nitrogen needs of 2 million hectares of wheat”1
III. Contemporary Challenges and Innovations
Despite its success, urea faces low efficiency (only 30-50% absorbed by crops) and environmental concerns. Emerging technologies include:
- Slow-release urea:Sulfur or polymer coatings control nitrogen release
- UAN solutions:Liquid formulations with 15-20% better uptake
- Nitrification inhibitors:Reduce nitrogen loss and N₂O emissions
References
1 IFA (2024). Global Urea Production and Use Statistics.
2 Smil, V. (2023). Harvesting the Air: The Haber-Bosch Legacy.
3 FAO (2024). Nitrogen Use Efficiency in World Agriculture.
