Macronutrients : The elements which are required in large amounts for plant growth are called macronutrients, e.g., nitrogen, phosphorus, sulphur, calcium, magnesium, etc. They are present in plant tissues in concetration of 1 to 10 mg/L of dry matter.
Micronutrients : The elements which are required in minute amounts (or trace amounts) for plant growth are called microments, e.g., iron, manganese, copper, molydenum, zinc, boron, chlorine and nickel. They are present in plant tissues in equal to or less then 0.1 mg/L of dry matter.
Beneficial nutrients : The elements which are requried by higher plants in addition to macro-and micronutrients are called beneficial nutrients e.g, sodium, silicon cobalt and selenium.
Toxic elements : A mineral element if supplied to plant tissues in such concentration which reduces the dry weight of tissues by about 10 percent is called toxic element.
Essential element : An essential element is that which must be directly involved in the metabolism of plant and must cause specific deficiency symptom if not supplied to the plant from external medium.
