Also known as mineral elements. When dry plant matter is fully burned, some off-white residue will be left behind, which is the so-called ash. Mineral elements exist in the ash in the form of oxides. If the ash is chemically analyzed, it will be found that it contains phosphorus, potassium, calcium, magnesium, iron, cobalt and other elements. These elements are usually called ash elements. Inorganic matter can be the residue after calcination or the residue after drying. But ash must be the solid part of a substance rather than the gas or liquid part. At high temperatures, a series of physical and chemical changes occur, and finally the organic components volatilize and escape, while the inorganic components (mainly inorganic salts and oxides) remain. These residues are called ash. Trace elements (plant) [microelement (plant)]
Elements that are necessary for normal life activities of plants but are required in extremely small amounts (10-5 to 10-8 of the plant's weight). Also known as micronutrients.
Research overview
J. von Sachs, W. When Knopp and others succeeded in cultivating plants with a solution of inorganic salts, in addition to carbon, hydrogen, and oxygen, they only knew that seven elements, including nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, and iron, were needed. Later, with the purification of the chemicals and water used, and the improvement of the quality of the glassware used for culture, since 1920, it has been gradually discovered that plants also need trace amounts of manganese, boron, zinc, copper, molybdenum, chlorine, sodium and other elements. The discoverers and year of discovery are shown in the table. Since iron is not needed in large amounts, it can also be counted as a trace element. Nutrients such as nitrogen, phosphorus, and potassium that are required in large amounts are called macroelements or macroelements.