Magie (Mg) – Magnesium

Plants absorb magnesium in the form of useful Mg²⁺

Mg²⁺ cycle

Origin: only in the soil

Source of Mg²⁺ supplement:

Soil minerals (dolomite, Mg sulfates …)

Fertilizers & soil improvers

New organic fertilizer

Mg loss pathways:

Wash drift (rough stone)

Crop is absorbed (in the course of cultivation does not fertilize containing Mg)

1. Effects of magnesium on plants:

– Magnesium (Mg²⁺) is an essential nutrient for plants, is an important component of chlorophyll and plays an important role in photosynthesis.

– In plants, Mg is absorbed as Mg²⁺ ions. Mg to the roots by moving by weight and diffusion. The amount of Mg absorbed by plants is usually less than Ca or K. Mg in chlorophyll molecules accounts for about 10% of total Mg²⁺ in leaves. Most of the plant’s Mg is in resin and cytoplasm.

Magnesium in chlorophyll (right) is like Iron in the blood (left)

– Mg²⁺ is classified as a secondary nutrient. Mg²⁺ performs some of the regulating, biochemical and physiological functions in plants such as chlorophyll formation, enzyme activation, protein synthesis and chromosome formation, carbohydrate metabolism and energy transport.

– The main structure of chlorophyll, the structural component of mitochondria, the mitochondrial stability in shape necessary for protein synthesis.

– Mg²⁺ required for maximum activity of most phosphorylating enzymes, glycine synthesis, …

– Mg²⁺ plays an important role in the entire metabolism of plants. Mg²⁺ helps plants, enhance photosynthesis, strong growth.

– In addition, Mg²⁺ also acts as a catalyst in the redox reactions in plant tissues. It also supports iron (Fe) activity and helps plants counteract the harmful effects of poor ventilation. By using a positive effect based on cell membranes and permeability membranes, Mg can increase resistance to drought and disease of the plant.

* Expression of plants lacking in magnesium:

Magnesium deficiency, leafy stems, appear yellow in the flesh of the old leaves while the main ribs remain green due to inadequate chlorophyll formation, which is susceptible to pests and diseases.

                                                            Leaf magma is necrotic, leaf vein is a Christmas tree

                                       The first symptom is light leaf, then the veins turn yellow. In some plants, red or purple spots may appear on the leaves.

The manifestation of symptoms depends very much on the intensity of light that the leaf is exposed to. Plants that are less exposed to light will experience more symptoms.

                                                                                       Lack of Mg on corn

                                                                            The old necrotic leaf necropsies

2. Types of fertilizers and compounds containing magnesium

2.1. Fused phosphate (Van Dien, Ninh Binh) contains 15 – 17% MgO.

So applying 60kg / ha P₂O₅ (360 kg dung) can provide 54kg MgO with enough MgO to ensure a good magnesium balance.

2.2. Iron phosphate (phosphate slag) contains 2 – 5% MgO

Phosphate fertilizers from slag sludge are used in agriculture in a number of countries.

Table Components of the basic slag: P₂O₅: 15 – 20%; Al₂O₃: 0.5 – 2.5%; CaO: 42 – 50%; Fe₂O₃: 9 – 13%; SiO₂: 4 – 6%; MnO: 3 – 6%; MgO: 2 – 5%

3. Potassium – magnesium sulphate contains 5 – 10% MgO

Mineral forms include:

+ Kainite: MgSO₄ • KCl • H₂O (19% K₂O, 12.9% S, 9.7% MgO)

+ Schönit: K₂SO₄ • MgSO₄ • 6H₂O

+ Leonite: K₂SO₄ • MgSO4 • 4H₂O

+ Langbeinite: K₂SO₄ • 2MgSO₄

+ Glaserite: K₃Na (SO₄)₂

+ Polyhalite: K₂SO₄ • MgSO₄ • 2CaSO₄ • 2H₂O

4. Dolomite and calcined dolomite:

Dolomite is a very limestone in our country. The magnesia ratio in dolomite is shown in the table below:

Can be used in the form of MgO (dolomite burning) or MgCO₃ (dolomite grinding). The percentage of MgO in dolomite is higher than that of dolomite. The percentage of MgO in some baked dolomite is as follows:

Firing from dolomite: 29.3 – 33.3% MgO

Calcined dolomite from limestone A 1.5 – 5.5% MgO

Calcined dolomite limestone B 15.5 – 29.3 MgO

5. Secpentin:

                                                                                         Secpentine ore

Secpentin is a silica mineral that contains 2Mg.2SiO₃.2H₂O or Mg₃H₄₂O₉, in addition to MgSiO₃ and some iron compounds. MgO content is 18 – 25% and SiO₂ is 40 – 48%.

6. Magnesium borate (admontite) contains 19% Mg

Admontite ore

Admontite is a mineral magnesium borate with chemical formula MgB₆O₁₀ · 7H₂O. It is named after Admont, Australia. This mineral has a hardness of 2 to 3.

7. Dunit and Kiserit ore.

Dunit Mg₂SiO₄ + Fe₂SiO₄ is an ore containing 24 – 28% MgO 35 – 39% SiO₂ and 3 – 8% FeO.

Mg₂SiO₄ is insoluble in water, but Mg can be exchanged with H-ions in the absorption complex, both ash and Mg – depleting.

Kiserit (MgSO₄.H₂O) and magnesium sulphate (MgSO₄.7H₂O) are two dissolved salts.

In Kiserit contains 29.13% MgO, magnesium sulphate contains 16.2% MgO.

8. Magnesium Chlorate (EDTA – Mg – 6)

                                                                          Magnesium Chelate (EDTA – MgNa₂)

Chemical name: Ethylenediaminetetraacetic acid, Magnesium – Disodium complex, Magnesium sodium ethylenediaminetetraacetate

Molecular formula: C₁₀H₁₂N₂O₈MgNa₂

Molecular weight: 358.52

pH = 6.5 – 7.5

Grayish white powder, well soluble and stable in water, soluble in water 99.95%