Hermann Hellriegel (October 21, 1831 – September 24, 1895)
was a German
agricultural chemist
Agricultural chemistry is the study of chemistry, especially organic chemistry and biochemistry, as they relate to agriculture—agricultural production (economics), production, the food processing, processing of raw products into foods and beverag ...
who discovered that
leguminous plants assimilate the free
nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
of the atmosphere.
Biography
He was born at Mausitz (now part of
Zwenkau
Zwenkau is a town in the district of Leipzig, in Saxony, Germany. Situated between the White Elster and Pleiße rivers, it nestles in the Leipzig Bay and includes parts of the conservation area ''Elsteraue'' and ''Central Germany's Street of Li ...
), in the
Kingdom of Saxony
The Kingdom of Saxony (german: Königreich Sachsen), lasting from 1806 to 1918, was an independent member of a number of historical confederacies in Napoleonic through post-Napoleonic Germany. The kingdom was formed from the Electorate of Saxon ...
. 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 f ...
of
Brandenburg
Brandenburg (; nds, Brannenborg; dsb, Bramborska ) is a states of Germany, state in the northeast of Germany bordering the states of Mecklenburg-Vorpommern, Lower Saxony, Saxony-Anhalt, and Saxony, as well as the country of Poland. With an ar ...
and
Niederlausitz
Lower Lusatia (; ; ; szl, Dolnŏ Łużyca; ; ) is a historical region in Central Europe, stretching from the southeast of the Germany, German state of Brandenburg to the southwest of Lubusz Voivodeship in Poland. Like adjacent Upper Lusatia i ...
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 architecture, Renaissance castle.
Geography
The town centre is situated ...
, where he died. From 1873 to 1882, he was ''Wanderlehrer'' (
circuit riding
In the United States, circuit riding was the practice of a judge, sometimes referred to as a circuit rider, traveling to a judicial district (referred to as a circuit) to preside over court cases there. A defining feature of American federal cour ...
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
Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns and ...
and
; 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 (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
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