Hermann Hellriegel
Hermann Hellriegel ( born October 21, 1831 in Mausitz at Pegau (Saxony ), † 24 September 1895 in Bernburg ) was a German agricultural chemist.
Hellriegel discovered in 1886 the ability of legumes to include elementary atmospheric nitrogen and make it available to plants when microorganisms invade the roots and form nodules. The elucidation of this fact is one of the most important discoveries in the field of plant physiology in the 19th century.
Life
Hermann Hellriegel - a farmer's son - first attended the Prince's School in Grimsby and then studied at the Agriculture and Forestry Academy in Tharandt. From 1851 to 1856 he was assistant there on agricultural chemistry laboratory Julius Adolph Stöckhardts. Stöckhardt sparked his interest in unsolved problems in the field of plant nutrition. 1854 doctorate Hellriegel at the University of Leipzig with a comprehensive 14-page dissertation on the germination of oil seeds imaging.
From 1857 to 1873 Hellriegel was head of the newly established Agricultural Experiment Station Dahme in Dahme / Mark. Since 1869, he held the title of professor. In 1873 he moved to Bernburg and was advisor to the Herzoglich Anhaltisches government. At the same time he worked as an agricultural migrant teachers. With the support of the Association for the beet sugar industry of the German Empire he founded in 1882 in Bernburg an agricultural experiment station. This station he directed until his death.
Although Hellriegel stood by his scientific work in the public eye and countless scientists sought out from home and abroad him in Bernburg, he remained a humble researcher. After 1890 he was the method of sand culture further improved. The experience acquired Hellriegel described in two papers that appeared posthumously.
Hellriegel was an honorary member of numerous scientific societies at home and abroad. 1889 Golden Liebig Medal he was awarded. Friends built him a monument in 1897 in Bernburg.
The method of sand culture
Hellriegel looked at the Agricultural Experimental Station Dahme his main task is to determine the nutrient requirements for the main agricultural crops. During his extensive fertilization experiments he used the method of sand culture. Culturing of test plants is carried in filled with sterile sand vessels. This method he developed into a globally recognized standard scientific method.
The main results of the Dahme fertilization experiments in which Hellriegel had also studied the influence of the factors of heat, light and water on yield of agricultural crops, he published in 1883 in a comprehensive nearly 800 page book entitled " Contributions to the fundamentals of science of agriculture with particular reference to the agricultural life - chemical method of sand culture. " This groundbreaking work is considered a "classic" of the scientific literature and has influenced farming in the following decades, especially the methodological research concepts in the fields of plant nutrition and fertilization sustainable.
The solution of the " nitrogen - question "
As head of the Experimental Station in Bernburg Hellriegel should give priority to explore the nutritional and cultural conditions of the sugar beet and explain the current problems at the time of the beet fatigue. Since the cultivation of beets with the method of sand culture initially prepared considerable problems, he also experimented with other crops to develop by comparative observations optimal for sugar beet cultivation methodology.
In the experiments conducted by Hellriegel with his assistant Hermann Wilfarth, it was observed that growing legumes grew in nitrogen-free sand to completely normal plants with the familiar " honk " at their roots, if they have previously " seeded " with an aqueous soil extract were. Further observations eventually led to the compelling conclusion that the source from which the with " nodule bacteria" infected legume cover their nitrogen requirements, could only be the elemental nitrogen from the atmosphere.
On September 20, 1886 Hellriegel reported at the annual meeting of the Society of German Natural Scientists and Physicians in Berlin for the first time about this discovery. It was a great moment for the agriculture science. The decades of high -discussed " nitrogen " question, the mystery of the origin of the large nitrogen profits in the cultivation of legumes, was thus finally resolved.
The experiments and their results, which led to this discovery, Hellriegel has published together with his longtime collaborator Hermann Wilfarth 1888 in the journal " Studies on the nitrogen nutrition of grasses and legumes ." Despite critical objections to individual researchers made the conclusion that Hellriegel had drawn from the results of these experiments do not refute. From then stood in the practice of farming intermediate crops and the design of crop rotations on a secured scientific foundation.
Publications
- Contribution to Keimungsgeschichte the oil -giving seed. Diss phil. Leipzig 1854.
- Contributions to the scientific principles of agriculture with particular reference to the agricultur - chemical method of sand culture. Braunschweig 1883.
- Studies on the nitrogen nutrition of grasses and legumes. Supplement to Bulletin of the journal of the Association of the beet sugar industry of the German Reich Vol 38, Berlin 1888 ( together with H. Wilfarth ).
- Fertilization trial and vegetation attempt. A talk about research methods. Work of the German Agricultural Society H. 24, 1897. (19 p )
- The method of sand culture. In: Works of the German Agricultural Society H.34, 1898, p.7 - 19th