鈥淎 butterfly can flap its wings in Peking, and in Central Park, you get rain instead of sunshine.鈥� That memorable quote comes from Jeff Goldbloom in Jurassic Park as he tries to explain how worldly events can be interrelated in a complex fashion. We now have just such a situation with the tragic war in the Ukraine. Its tentacles are reaching all over the world, causing problems ranging from the manufacture of silicon chips for computers to shortages in fertilizer. Ah, fertilizer! To put it simply, fertilizer feeds the plants that feed the world. Russia and Ukraine are prime producers of fertilizer and a disruption in production is set to have global consequences.
By the 1800s, scientists had begun to understand the nuances of agriculture. Through photosynthesis, carbon dioxide from the air supplied plants with the carbon and oxygen they need for growth. Hydrogen, also required, was available from water. But potassium, phosphorous and nitrogen, all essential, had to be supplied by the soil. Once the earth was depleted of these minerals, it would become infertile. The situation could be remedied, the minerals replenished, and the soil made fertile again by ploughing in manure or plant wastes. Unfortunately, it was also becoming clear that even the most efficient recycling of waste products as 鈥渇ertilizer鈥� would not be enough to sustain the growing population. Supplying nitrogen for crops was a particular problem. This may seem strange since about 78% of the air is made up of nitrogen. But with the exception of legumes, plants cannot use nitrogen in this 鈥渆lemental鈥� form. Legumes have bacteria growing on their roots that can convert the gaseous nitrogen of the air into a usable form. All other crops, though, have to rely on compounds of nitrogen in the soil.
During the 19th century, the major source of nitrogen fertilizer in Europe was guano (bird poop) imported from South America or some Pacific islands. Still, all the bird droppings that Europeans could import were not enough to feed the growing agricultural industry. Luckily, though, large deposits of sodium nitrate, better known as saltpeter, were discovered in the Chilean desert. This was an excellent source of nitrogen but would not last forever. Many scientists predicted massive starvation when the saltpeter ran out.
German chemist Fritz Haber turned his attention to this problem in 1904. As he saw it, the solution lay in finding a way to make use of the vast amount of nitrogen available from the atmosphere. Two years earlier, Carl von Linde had succeeded in liquefying air by first compressing it and letting it expand rapidly, thereby cooling it. The liquid air he obtained was readily separated into oxygen and nitrogen by distillation. Haber found that if this nitrogen were reacted with hydrogen under pressure, ammonia (NH3) formed. A breathtaking discovery! Ammonia gas could be pumped directly into soil as a fertilizer, or even better, could be converted into water-soluble ammonium nitrate by reaction with nitric acid, which itself could be made from ammonia. Urea, also produced from ammonia, eventually proved to be an even more efficient fertilizer than ammonium nitrate. In 1909, Haber demonstrated his process to the chemists at the Badische Anilin und Soda Fabrik (BASF) who under the leadership of Karl Bosch then worked out the final details of the industrial large-scale manufacture of ammonia. Haber deservedly received the Nobel Prize for his discovery, but his legacy remains tarnished by his involvement in producing chemical warfare agents during World War 1.
Today, Ukraine and Russia both have extensive facilities to produce fertilizer for their own use and for export. Besides nitrogen fertilizers that also produce potash, a source of potassium. Interestingly, in this case Canada may benefit from a reduction of exports from the Ukraine and Russia since the country has a large potash industry. Ukraine and Russia are also huge producers of natural gas (methane) that is needed to react with steam to make the hydrogen required for the Haber-Bosch synthesis of ammonia. Ukraine鈥檚 production of potash and ammonia has been significantly disrupted by the war and Russia鈥檚 exports have been hit by sanctions. As a result, the world鈥檚 food supply is affected. While, we may only note this at the cash register, some areas of the developing world are likely to experience actual shortages and hunger.
It is sad and very disturbing to see how the same species that has produced Newtons, Pasteurs and Einsteins, also produces war-mongers who care not an iota about human life.
