Essential Major Elements and Trace Elements for Plant
The plant ash reveals the presence of 40 elements but all are not essential for plant nutrition, only a few are essential for growth and development of plants. These are called the essential elements. The essential elements may be grouped as major elements ormacronutrients and trace elements or micro nutrients, based on their requirement by plants.
These elements are required in large amounts and form the plant consituents. The major elements are otherwise known asmacronutrients. These include carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium and sulphur.These elements form an integral part of complex organic molecules. Some of these elements help in the functioning of enzyme systems. The sources of macronutrients are generally the soil or the atmosphere. Carbon is got from carbodioxide of the atmosphere.Oxygen is derived from water and atmospheric oxygen. Nitrogen is present in the atmosphere as an inert substance which is brought to the soil and converted to soluble nitrates either by asymbiotic or symbiotic nitrogen fixation. Phosphorous and sulphur and derived from rocks during weathering. The source of hydrogen is water.
Elements like iron, boron, managanese, copper, zinc and molybdenum are required for plants only in very small amounts but these are indispensable for the normal growth and development of plants.