Hermann Hellriegel (October 21, 1831 – September 24, 1895) was a German agricultural chemist who discovered that leguminous plants assimilate the free

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

of the atmosphere.

Biography

He was born at Mausitz (now part of Zwenkau), in the

Kingdom of Saxony The Kingdom of Saxony () was a German monarchy in Central Europe between 1806 and 1918, the successor of the Electorate of Saxony. It joined the Confederation of the Rhine after the dissolution of the Holy Roman Empire, later joining the German ...

. In 1857 he became director of the

agricultural experiment station An agricultural experiment station (AES) or agricultural research station (ARS) is a scientific research center that investigates difficulties and potential improvements to food production and agribusiness. Experiment station scientists work with ...

Brandenburg Brandenburg, officially the State of Brandenburg, is a States of Germany, state in northeastern Germany. Brandenburg borders Poland and the states of Berlin, Mecklenburg-Vorpommern, Lower Saxony, Saxony-Anhalt, and Saxony. It is the List of Ger ...

and Niederlausitz at Dahme, from which he resigned in 1873, and in 1882 accepted a similar post at

Bernburg Bernburg (Saale) () is a town in Saxony-Anhalt, Germany, capital of the Salzlandkreis district. The former residence of the Anhalt-Bernburg princes is known for its Renaissance castle. Geography The town centre is situated in the fertile Magdeb ...

, where he died. From 1873 to 1882, he was ''Wanderlehrer'' ( circuit riding teacher) at Bernburg.

Nitrogen fixation

Among his many agricultural investigations with plants, the most important by far are his demonstration of the ability of leguminous plants to assimilate the free nitrogen of the air, and his discovery of the tubercles on the roots as the agency through which this takes place. The question of the ability of leguminous plants to use the nitrogen of the air had long been one of inquiry, and its settlement by him marked an epoch in the agricultural world. The important parts of these experiments he published in ''Untersuchungen über die Stickstoffnahrung der Gramineen und Leguminosen'' (Investigations into the Nitrogen assimilation of the Gramineae and

Leguminosae Fabaceae () or Leguminosae,International Code of Nomen ...

; Berlin, 1888), and ''Ueber Stickstoffnahrung landwirtschaftlicher Kulturgewächse'' (On Nitrogen assimilation in agricultural crops; Vienna, 1890). Hellriegel and Wilfarth (1887) "grew plants in calcined soil as others had done, but to some of the pots they added leachings from a fertile soil, in other words, an inoculum containing

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

of the proper species and variety. They found that peas growing in inoculated soils produced root nodules, and after an initial period of nitrogen deficiency, turned green and made thrifty growth. On the contrary, peas in a similar soil without an inoculum were unthrifty and perished prematurely."Howard S. Reed (1942) ''A Short History of Plant Science'', page 230, Chronica Publishing

Notes

References

* This work in turn cites: **Römer, ''Hermann Hellriegel, Nachruf'' (Leipzig, 1896)

External links

* {{DEFAULTSORT:Hellriegel, Hermann 1831 births 1895 deaths People from Zwenkau People from the Kingdom of Saxony German agronomists 19th-century German chemists German male writers