http://geoengineeringourclimate.com/2013/07/09/nitrogen-geoengineering-opinion-article/

NITROGEN GEOENGINEERING (OPINION ARTICLE)

"In the 1870s strategic control of the richest South American nitrate deposits were a principal cause of the “War of the Pacific” (also called the Saltpetre War) between Chile, Peru and Bolivia."

"Noting the ever-greater demand for wheat and the lack of new land on which to grow it, Sir William Crookes, a noted British chemist, used his 1898 presidential address to the British Association for the Advancement of Science to stress that it was “vital to the progress of civilized humanity” that chemists solve the problem by fixing nitrogen from the air into compounds that could be used as fertilizers and chemical feedstocks. If they failed there would be a planet-wide “catastrophe little short of starvation…and even the extinction of gunpowder!”[3] In 1908 Fritz Haber hit on a successful scheme; Carl Bosch made its use a practical industrial process, and Germany’s need for explosives in the First World War saw the process put into large-scale use.[4] By the 1920s the Haber-Bosch process was available to industries throughout the world and chemistry textbooks were congratulating themselves on having solved the “nitrogen problem”."

"It has been estimated that the explosives made possible by the Haber Bosch contributed directly to 150 million deaths over the twentieth century.[5] In the second half of the century, though, it made an even greater contribution to life than it had to death. Nitrogen-based fertilizers were the single greatest contributor to near tripling of crop yields in the decades after 1950. Today fertilizers produced by the Haber-Bosch process account for almost half of the nitrogen in human food; without them the population would not have been able to grow close to its present seven billion. By the time the population stabilizes somewhere around 10 billion, most of the nitrogen in those peoples muscle fibers, nerve cells and DNA will be coming from factories."

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"There are other aspects of nitrogen geoengineering that climate geoengineers should be aware of. One is that it is deployed inefficiently. Most of the deliberately fixed nitrogen does not get into crops; Vaclav Smil estimates that the overall efficiency of the global food system seen this way is less than 15%.[6] The wasted nitrogen is not just a loss; it often does harm."