What is Magnesium?

Magnesium in Nature

Magnesium is abundant in the earth’s crust. It is found in a wide variety of minerals which becomes available for plant use as they weather or break down. Magnesium is held on the surface of clay and organic matter particles. Although this exchangeable form of Mg is available to plants, this nutrient will not readily leach from soils.

Functions of Magnesium

Magnesium is required to help plants capture the sun’s energy for growth and production through photosynthesis. Photosynthesis takes place in chlorophyll, the green pigment in plants, and magnesium is the central atom of the chlorophyll molecule, with each chlorophyll molecule containing 6.7% magnesium.

Magnesium also plays a significant role in activating enzymes involved in respiration, photosynthesis, and nucleic acid synthesis. It aids in phosphate metabolism, serving as a carrier of phosphate compounds throughout the plant. Magnesium facilitates the translocation of carbohydrates (sugars and starches), enhances the production of oils and fats, and is necessary for cell division and growth.

Human Needs

An adult body contains around 25g of magnesium. Many types of foods contain magnesium including leafy green vegetables, whole grains, beans, nuts, and fish.

Magnesium in Plants & the Environment

To ensure healthy and nutritious plant growth, adequate supplies of magnesium must be maintained in the soil by judicious use of fertilisers and manures. Some soils are naturally high in magnesium which can have a negative impact on soil structure as clay particles can be held tightly together when dry and very loose when wet.