Hermann Hellriegel

Hermann Hellriegel

Grave of Hermann Hellriegel in Bernburg

Hermann Hellriegel (born October 21, 1831 in Mausitz , † September 24, 1895 in Bernburg ) was a German agricultural chemist .

Hellriegel discovered in 1886 the ability of legumes to absorb elemental nitrogen from the air and make it available to plants when microorganisms penetrate the roots and form nodules . The clarification of this fact is considered to be one of the most important discoveries in the field of plant physiology in the 19th century.

Life

Hermann Hellriegel - son of a farmer - first attended the Princely School in Grimma and then studied at the Agriculture and Forestry Academy in Tharandt . From 1851 to 1856 he was an assistant at Julius Adolph Stöckhardt's agricultural chemistry laboratory . Stöckhardt aroused his interest in unsolved problems in the field of plant nutrition. In 1854 Hellriegel received his doctorate from the University of Leipzig with a 14-page dissertation on the germination of oil-giving seeds.

From 1857 to 1873 Hellriegel was the head of the newly founded agricultural research station Dahme in Dahme / Mark . Since 1869 he held the title of professor. In 1873 he moved to Bernburg and became an advisor to the Ducal Anhalt government. At the same time he worked as an agricultural hiking instructor . With the support of the Association for the Beet Sugar Industry of the German Reich , he founded an agricultural research station in Bernburg in 1882, which later became an agricultural college and is now part of the Anhalt University of Applied Sciences . He headed this station until his death.

Although Hellriegel was in the public eye for his scientific work and countless scientists from home and abroad visited him in Bernburg, he remained a modest researcher. After 1890 he further improved the method of sand culture. Hellriegel described the experience he gained in two papers that appeared posthumously .

Hellriegel was an honorary member of numerous scientific specialist societies in Germany and abroad. From 1892 he was a corresponding member of the Académie des Sciences in Paris. In 1889 he was awarded the Golden Liebig Medal . Friends erected a memorial to him in Bernburg in 1897.

The method of sand culture

At the agricultural research station in Dahme, Hellriegel saw his main task in determining the nutrient requirements for the most important agricultural crops. In his extensive fertilization experiments he used the method of sand culture . The test plants are grown in vessels filled with sterile sand. He developed these procedures into a globally recognized standard scientific method.

The most important results of the fertilization tests carried out in Dahme, in which Hellriegel had also examined the influence of the factors heat, light and water on the yield formation of agricultural crops, he published in 1883 in a book of almost 800 pages under the title “Contributions to the scientific fundamentals of arable farming with special consideration of the agricultural-chemical method of sand culture ”. This groundbreaking work is considered to be a "classic" of scientific agricultural literature and, in the decades that followed, had a lasting influence on methodical research concepts in the fields of plant nutrition and fertilization.

The solution to the "nitrogen question"

As head of the research station in Bernburg, Hellriegel was primarily supposed to research the nutritional and cultural conditions of the sugar beet and to clarify the current problem of beet fatigue at the time . Since the cultivation of beets with the sand culture method initially caused considerable problems, he also experimented with other cultivated plants in order to develop an optimal cultivation method for sugar beet through comparative observations.

In the experiments that Hellriegel carried out with his assistant Hermann Wilfarth , it was observed that legumes growing in nitrogen-free sand grew into completely normal plants with the well-known “nodules” on their roots if they were “inoculated” beforehand with a watery soil extract. Further observations finally led to the compelling conclusion that the source from which the legumes infected with “nodule bacteria” meet their nitrogen requirements could only be elemental nitrogen from the atmosphere.

On September 20, 1886, Hellriegel reported on this discovery for the first time at the annual meeting of the Society of German Natural Scientists and Doctors in Berlin. It was a great moment for agricultural science. The “nitrogen question”, which had been intensely discussed for decades, the riddle about the origin of the large nitrogen gains from the cultivation of legumes, was finally solved.

The experiments and their results that led to this discovery were published by Hellriegel, together with his long-time colleague Hermann Wilfarth, in 1888 in the publication “Investigations on the nitrogen nutrition of the Gramineae and legumes”. Despite critical objections from individual researchers, the conclusion that Hellriegel had drawn from the results of these experiments could not be refuted. From then on, in the practice of land management of the catch crops and the design of crop rotations on a solid scientific foundation.

Publications

• Contribution to the germination history of the oil-giving seeds . Diss. Phil. Leipzig 1854.
• Contributions to the scientific principles of arable farming with special consideration of the agricultural-chemical method of sand culture . Brunswick 1883.
• Investigations into the nitrogen diet of the gramineae and legumes . Supplement to the magazine of the Association of the Beet Sugar Industry of the German Reich, Vol. 38, Berlin 1888 (together with H. Wilfarth).
• Fertilization trial and vegetation trial. A chat about research methods . Work of the German Agricultural Society, issue 24, 1897. (19 pages)
• The method of sand culture . In: Work of the German Agricultural Society H. 34, 1898, pp. 7-19.

literature

• Carl Leisewitz:  Hellriegel, Dr. Hermann . In: Allgemeine Deutsche Biographie (ADB). Volume 50, Duncker & Humblot, Leipzig 1905, pp. 169-171.
• Ludwig Schmitt :  Hellriegel, Hermann. In: New German Biography (NDB). Volume 8, Duncker & Humblot, Berlin 1969, ISBN 3-428-00189-3 , p. 488 ( digitized version ).
• H. Wilfarth: Hermann Hellriegel † . In: The agricultural test stations, Vol. 46, 1896, pp. 1–8 (with picture and list of the most important publications).
• H. Römer: Hermann Hellriegel. Obituary . In: Zeitschrift für Naturwissenschaften Vol. 69, 1896, pp. 1–8.
• G. Wimmer et al.: Memorandum to commemorate the 50th anniversary of the Anhalt Research Station in Bernburg 1882-1932 . In: Journal of the Association of the German Sugar Industry Vol. 82, 1932, Techn. Part, pp. 277-315 (with a complete list of Hellriegels publications).
• O. Lemmermann: Hellriegel's studies on the nitrogen nutrition of the Gramineae and legumes . In: Journal for plant nutrition, fertilization and soil science, Part A, Vol. 45, 1936, pp. 257-276.
• Wolfgang Böhm : The fixation of elementary nitrogen by the root nodules of legumes. In memory of Hermann Hellriegel's epoch-making discovery in 1886 . In: Angewandte Botanik Vol. 60, 1986, pp. 1-5 (with picture).
• Wolfgang Böhm: The nitrogen question in agricultural science in the 19th century . In: Journal of Agricultural History and Agricultural Sociology Vol. 34, 1986, pp. 31–54.
• Martin Stolzenau: Tharandt academician solves the nitrogen question , In: Sächsische Zeitung, Freital edition, September 28, 2011

Web links

• Literature by and about Hermann Hellriegel in the catalog of the German National Library