Essential Mineral Elements for Plants

Most of the mineral elements present in soil are absorbed by roots of the plant. But all are not essential. Only 17 elements are considered as essential for the plants. The nutrients or elements which are essential for the healthy growth of the plant are called essential nutrients or essential elements. The roots absorb about 60 elements from the soil.

Types of Essential Elements

Essential elements may be required in small amounts or large amounts. Accordingly they have been grouped into two categories.

Micro elements or Micro nutrients

These are required in minute quantities like 0.1 mg per gram of dry matter or less than that. Also called as trace elements.

Examples: Manganese, Boron, cobatt Copper, Molybdenum, Iron, Zinc and Chlorine are required in very small quantities.

Macro elements or Macro nutrients

These are required in relatively large quantities like one to 10 milligram per gram of dry matter.

Examples: Carbon, Hydrogen, Oxygen Phosphorous, Potassium, Calcium and magnesium, Nitrogen, Sulphur.

Sources of Essential Elements for Plants

Most of the essential elements are taken from soil, and some from the atmosphere.

Carbon: Taken as CO2 from the atmosphere (air).

Oxygen: Absorbed in the molecular form from air or from water. It is also generated within a green plant during photosynthesis.

Hydrogen: Released from water during photosynthesis in the green plant.

Nitrogen: Absorbed by the plants as nitrate ion (NO3) or as ammonium ion (NH4+) from the soil. Some organisms like bacteria and cynobacteria can fix nitrogen from air directly.

Potassium, calcium, iron, phosphorus, sulphur, magnesium: absorbed from the soil in the ionic forms e.g. K+, Ca2+, Fe3+, H2PO4/ HPO42–