Ultimately, are based fertilizer on plant nutrition has long been known nutrient solutions. Depending on the purpose (whether used in agriculture and horticulture NPK fertilizer or fertilizer used in horticulture and other crops), however, they are composed very differently. Their common characteristic is that they have the task of ensuring a continuous supply of the necessary nutrients. Already in 1840 showed the Giessen chemist Justus v. Liebig (1803-1873) in his work “The Organic Chemistry in its Application to Agriculture and Physiology” the importance of the mineral components, resulting from the decay of plant and animal residues. He came to the conclusion that the plants find the components of carbon, hydrogen, oxygen and nitrogen in abundance, so that the supply of these substances is superfluous by fertilization. KARL SPRENGEL provided further evidence that certain, though extremely small amounts of mineral components for the life and prosperity of plants are equally important.
The first synthetic nutrient solution was produced by J. v. SACHS ago in collaboration with the chemist J. A. STÖCKHARDT. It contains up to 1000 ml of water: 1 g of potassium nitrate, 0.5 g of calcium sulphate, 0.4 g of magnesium sulfate, 0.5 g calcium hydrogen phosphate, and a trace of iron (III) chloride.
1861 developed JALW KNOP named after him and still much used Knopsche broth: it contains up to 1000 ml of water. 1 g calcium nitrate, 0.25 g of magnesium sulfate, 0.25 g of potassium dihydrogen phosphate, 0.25 g of potassium nitrate and a trace of iron sulfate < / p>
The absence of one of the elements can not be compensated by an excess of another (it chemically related). Atmospheric nitrogen, metallic potassium or elemental sulfur may also not be used. Required are the respective ions.
This, however, not all the elements needed by a plant to be covered. It still lacks the trace elements, even indirectly provided evidence for their requirement Sprengel.
R. D. HOAGLAND (1884-1949) presented a solution of trace elements together, add the 1 ml to a standard nutrient solution is: In 18 liters of water are dissolved: 0.5 g of lithium chloride, 1 g of copper sulfate, 1 g of zinc sulfate, 11 g of boric acid, 1 g of aluminum sulfate, 0.5 g of tin chloride, 7 g of magnesium chloride, 1 g of nickel sulfate, 1 g of cobalt nitrate, 0.5 g of potassium iodide, 1 g of titanium oxide, 0.5 g of potassium bromide. This is also referred to as A-Z trace element solution, most of the required organisms trace elements are covered. After today’s mind, boron, copper, manganese, zinc and molybdenum are always needed. Nevertheless, there is evidence that other trace elements such as molybdenum, zinc or cobalt are required (for the synthesis of vitamin B12) from several organisms.
In the hunting is for “normal” planted community tank The situation is different than that of nitrogen (mainly in the form of nitrate) and phosphorus (in the form of phosphate) mostly in sufficient quantity, if not exist even in excess. The main source of these two elements is the fish feed, which is at least partially supplied via the detour of the animal to water plants. These elements are therefore in water plant fertilizers for aquarium usually not necessary (except plants are heavily dominated, fish aquariums poor). However, the other necessary trace elements are very often lack Substances which should additionally supplied in order to achieve a stable, strong plant growth and to maintain.
Good water plant fertilizer for community tanks such as the Fermendo system are therefore free of nitrogen and phosphorus and are oriented in the composition of the A-Z solution of Hoagland.
Nutritional salts on www.biologie.uni-hamburg.de
Knops nutritional solution on www.biologie-lexikon.de