Magnesium plant micronutrient

Shivashankar, K., and Hagstrom, G. R. (1991). Molybdenum fertilizer sources and their use in crop production. In International Symposium on the Role of Sulphur, Magnesium ami Micronutrients in Balanced Plant Nutrition (1991 Sichuan, China), ed. S. Portch, pp. 297-305 Hong Kong Potash and Phosphate Institute. 

The evolution of a lake or pond into dry land depends on the presence of nutrients in the water. The term nutrients refers to elements and compounds that are necessary for the growth of plants. Nutrients are commonly divided into two categories major nutrients and minor nutrients, also known as micronutrients. Despite some differences in the way that various elements and compounds are classified, carbon, nitrogen, and phosphorus are always regarded as major nutrients. Some authorities also list potassium, sulfur, calcium, magnesium, and/or iron as major nutrients. Micronutrients include aluminum, boron, chlorine, copper, manganese, molybdenum, silicon, and zinc. 

Micronutrients are elements such as Boron, Zinc, Copper, Cobalt, Iron, Magnesium etc. which are required in trace amounts. The addition of extra trace elements has no effect on plant growth but a deficiency of any or all of these can cause serious disturbance of plant growth, leading to a loss of active chemical. Since plants can be cultivated in areas with different soils of varying fertility, it follows that the site of cultivation could influence quality, indicating again the need for assays for chemical content. 

There are thirteen mineral nutrients that plants obtain from the soil, and these are divided into the categories of macronutrients and micronutrients. The primary macronutrients include nitrogen, phosphorus, and potassium. Plants require these primary macronutrients in relatively large quantities and deplete them from the soil more rapidly than others. The secondary macronutrients include calcium, magnesium, and sulfur. Micronutrients are required in smaller quantities than the macronutrients, and these include boron, copper, iron, chloride, molybdenum, manganese, and zinc. 

Secondary nutrients and micronutrients usually are expressed on an elemental basis althou calcium and magnesium sometimes are ejq ressed in the oxide form. However, several countries express all plant nutrients on an elemental basis. Plante actually use neither tile pure element nor the pure oxide form, so the difference is largely academic. Conveireion factors for those plant nutrients that may be expressed in the elemental or oxide form, depending on the country, are shown in Table 1.2. 

The secoixlary nutrients are calcium, magnesium, and sulfur. Concentrations of these nutrients in plant tissues generally are lower than those of the primary nutrients (nitrogen, phosphorus, and potassium) but are higher than those of the micronutrients. The seven micronutri-ents are boron, chlorine, copper, iron, manganese, molybdenum, and zinc, Because chlorine deficiencies rarely occur in nature, most discussions on supplying micronutrient fertilizers are confined to the other six micronutrients. 

Essential mineral elements can be classified into the major elements, calcium, magnesium, potassium, sodium, phosphorus, sulfur and chlorine and essential trace elements (sometimes described as micronutrients) such as copper, manganese, iron, zinc, molybdenum, cobalt, iodine and boron. All of these elements are required for the normal growth and maintenance of health in plants and animals, cobalt being specifically necessary for animals, and boron for plants. 

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