(I) ORIGIN OF MINERAL FERTILIZATION

¿Where do we come from? => Origin of the Mineral Fertilization (NPK)

19th Century, German Chemist  Justus von Liebig, probed the key role of 3 mineral elements for plants development.

Nitrogen (N), Phosphorus (P) and Potassium (K)

(well known NPKs formulation).

Justus proposed (wrongly) that plants only extract mineral elements from the soil, therefore to increase soil fertility it was only necessary to increase the contribution of these mineral elements.

Since then, the objective of the great world economic powers has been to obtain natural sources of these three elements in their mineral form:

Sources of Nitrogen (N)

Since the mid-19th century, the first source of production was GUANO (from Quechua: wanu) (excrements of seabirds and bats), the natural one contains between 8 and 16% nitrogen, 8 to 12% of phosphoric acid and 2 to 3% potash equivalent.

Millions of tons of this resource were extracted in Peru in the second half of the 19th century and sent to the US, England and the rest of Europe (Holland, Belgium, France, Sweden…)

Later the NITRATE arrived (end of the 19th century) the main deposits were found in the desert in the north of Chile in the regions of Atacama, Antofagasta and Tarapacá.

The dispute over the exploitation of the GUANO and NITRATE deposits, came to provoke the so-called “Saltpeter War” (1879-1884) between Chile (supported by England) and the alliance of Bolivia and Peru.

Finally at the beginning of the s. In the 20th century, the German chemist Fritz Haber discovered how to extract nitrogen from the air by synthesizing ammonia.

German chemist Carl Bosch perfected Haber’s method for obtaining synthetic ammonia, which became known as the “Haber-Bosch process” for which he was awarded the Nobel Prize in Chemistry in 1931.

By means of this method it was possible to synthesize ammonia gas in the manufacture of artificial fertilizers, thus the guano was replaced by synthetic fertilizers.

This process requires the use of natural gas as an energy source to provide the hydrogen needed in the reaction, which means a great dependence on fossil fuels for food production.

Sources of Phosphorus (P)

In 1840, John Lawes discovered the manufacturing process of superphosphates attacking phosphate rocks with sulfuric acid.

Superphosphates became the very first artificial fertilizers which quickly started to be manufactured at large scale by industry.

European reserves of phosphate rock were limited, the search for deposits motivated French and Spanish colonialism in North Africa

More than 80% of the World’s phosphate resources are found in Western Sahara

Other important deposits are located in:

Sources of Potassium (K)

The main natural source since the ancient Greeks and Romans had been plant ash.

In 1861 => The first mineral potash factory is created, from the exploitation of the recently discovered deposits of Stassfurt (Germany).

Subsequently, other important deposits were exploited, such as those in Alsace, then under German control, or those in Suria, in Cataluña.

Currently most of the world’s reserves are concentrated in Canada, Belarus, Russia, China and Israel.

Just as we have seen, the most accepted theory of fertilization comes from pre-industrial Europe in the mid-19th century and was the beginning of chemical agriculture.

Liebig’s mistake was to assume that it was enough to add mineral elements to the soil to maintain and increase its fertility.

Today, after decades of purely mineral contributions, reality has just shown us the opposite… (continues in next Post)

D.LAHOZ