Magnesium

Magnesium (Mg) is the central atom of the chlorophyll molecule, making up about 20% of its structure, which makes it critical for photosynthesis.

This element acts as an activator for over 300 enzymatic reactions, participating in the synthesis of proteins, carbohydrates, fats, and organic acids.

It plays a key role in energy transport, facilitating ATP formation and ensuring energy metabolism within all plant cells.

Magnesium contributes to better absorption of phosphorus and nitrogen, increasing the overall efficiency of the mineral nutrition system in crops.

The element is also involved in the synthesis of pectin substances in cell walls, which provides mechanical strength and resistance to lodging.

The main symptom of magnesium deficiency is interveinal chlorosis of the lower leaves, occurring due to the plant's ability to remobilize magnesium to young tissues.

In cases of severe deficiency, leaf margins begin to curl, and the tissue between the veins takes on a yellow, orange, or reddish color while the veins remain green.

Magnesium toxicity is rare, but it can lead to antagonism with calcium and potassium, blocking their uptake by the root system.

Visually, excessive magnesium content can manifest as stunted root growth and delayed development of vegetative plant mass.

To prevent imbalances, soil testing is necessary, as symptoms of excess are often masked by the deficiency of other cations.

Magnesium application rates depend on soil type, crop variety, and nutrient availability, typically ranging from 20 to 80 kg of active ingredient per hectare.

The most popular fertilizers include magnesium sulfate, potassium-magnesium sulfate, dolomitic lime, and magnesium nitrate, which differ in absorption rates.

The primary dose of magnesium is recommended for pre-sowing cultivation or plowing to ensure uniform distribution within the topsoil layer.

For quick correction of deficiency during the growing season, foliar feeding with soluble magnesium salts at a 1–3% concentration is highly effective.

Application frequency is determined by crop rotation: crops with high nutrient extraction (potatoes, sugar beets, cereals) require annual replenishment.

Magnesium is most actively leached from light sandy and loamy soils, where the efficiency of a single application is significantly lower.

High potassium levels in the soil can block magnesium uptake by the plant, making it crucial to maintain a proper K:Mg balance in the fertilization program.

Acidic soils reduce magnesium availability; therefore, liming with dolomitic lime is the preferred method for correcting both acidity and nutrient levels.

Under drought conditions, soil application efficiency decreases, so preference should be given to fertigation or foliar treatments.

It is necessary to consider the antagonism between magnesium and ammonium or calcium ions, which requires split applications when using complex mineral fertilizers.