Hermann Hellriegel was a noted German

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 agricultural chemist who discovered the mechanism by which leguminous plants assimilate the free nitrogen

Nitrogen

Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

 of the atmosphere.

Biography

He was born at Mausitz (near Pegau

Pegau

Pegau is a town in the Leipzig district in the Free State of Saxony, Germany, situated in a fertile country, on the Weiße Elster, 18 m. S.W. from Leipzig by the railway to Zeitz....

), in Saxony

Kingdom of Saxony

The Kingdom of Saxony , lasting between 1806 and 1918, was an independent member of a number of historical confederacies in Napoleonic through post-Napoleonic Germany. From 1871 it was part of the German Empire. It became a Free state in the era of Weimar Republic in 1918 after the end of World War...

. In 1857 he became director of the agricultural experiment station

Agricultural experiment station

An agricultural experiment station is a research center that conducts scientific investigations to solve problems and suggest improvements in the food and agriculture industry...

 of Brandenburg

Brandenburg

Brandenburg is one of the sixteen federal-states of Germany. It lies in the east of the country and is one of the new federal states that were re-created in 1990 upon the reunification of the former West Germany and East Germany. The capital is Potsdam...

 and Niederlausitz at Dahme

Dahme

Dahme may refer to:*Dahme, Brandenburg, a town in Brandenburg, Germany*Dahme, Schleswig-Holstein, a municipality in Schleswig-Holstein, Germany*Dahme , a river in Brandenburg, Germany*Dahme-Spreewald, a district of Brandenburg, Germany...

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

Bernburg

Bernburg is a town in Saxony-Anhalt, Germany, capital of the district of Salzlandkreis. It is situated on the river Saale, approx. 30 km downstream from Halle. The town is dominated by its huge Renaissance castle featuring a museum as well as a popular, recently updated bear pit in its...

, where he died. From 1873 to 1882, he was Wanderlehrer (circuit riding

Circuit rider

Circuit rider is a term originating from the United States for any professional who travels a regular circuit of locations to provide services, and has several specific applications:...

 teacher) at Bernburg.

Nitrogen fixation

Among his many agricultural investigations with plants none rank in importance with 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; Berlin, 1888), and Ueber Stickstoffnahrung landwirtschaftlicher Kulturgewächse (On Nitrogen assimilation in agricultural crops; Vienna, 1890).