On the Origin of the Theory of Mineral Nutrition of Plants and the Law of the Minimum

Modern treatises on the origin of the theory of mineral nutrition of plants and the Law of the Minimum usually refer to books published by Justus von Liebig in 1840 and 1855. These works are believed to be original reports of Liebig's own research. Occasionally, however, scholars of early agronomic literature have stated that these books by Liebig contain doctrines on mineral plant nutrition and nutrient deficiencies that had been published earlier by Liebig's countryman and colleague Carl Sprengel (1787–1859). To examine such statements, we studied the relevant literature. This study showed that the agronomist and chemist Carl Sprengel conducted pioneering research in agricultural chemistry during the first half of the 19th century. His early articles and books mark the beginning of a new epoch in agronomy. He published in 1826 an article in which the humus theory was refuted, and in 1828 another, extended journal article on soil chemistry and mineral nutrition of plants that contained in essence the Law of the Minimum. Sprengel's doctrines are presented again in the books published by Liebig in 1840 and 1855. To avoid a dispute on priorities and impacts and to recognize and commemorate the achievements of both pioneering scientists, the Association of German Agricultural Experimental and Research Stations has created the Sprengel‐Liebig Medal. We propose that the international community of agronomists acts similarly by recognizing Sprengel as a cofounder of agricultural chemistry and that the Law of the Minimum henceforth be called the Sprengel‐Liebig Law of the Minimum.