Magnesium is a chemical element of symbol Mg atomic number 12 (12 protons and 12 electrons) with atomic mass 24 u. It is a metal alkaline earth , solid at ambient conditions.
MG SOURCES
Magnesium is the eighth most abundant element in the earth's crust. The average content of Mg in the earth's crust is 19.3 g kg -¹, varying according to the geological origin of the soil. Mg is the soil in the forms: non-exchangeable, exchangeable and soil solution. The Mg in the non-exchangeable form is found mainly in primary and secondary minerals such as biotite, augite, horblenda, olivine, serpentinite, chlorite, montmorillonite, illite, vermiculite, and carbonate minerals such as dolomite and Magnesita.
MG IN AGRICULTURE
The cultures Magnesium require relatively small quantities of the order of 10 kg / ha to 40 kg / ha in most cases. The supply of magnesium to crops is commonly done by means of dolomite lime, although they are also used Magnesite and magnesium oxide.
PHYSIOLOGICAL FUNCTION
- One of the important functions of magnesium as a central element of the chlorophyll molecule, is participation in photosynthesis;
- Activator of enzymatic reactions;
- Influences the movement of the sheets of carbohydrates to other plant parts;
- It stimulates the uptake and transport of phosphorus in the plant.
MAGNESIUM ABSORPTION WAYS
Mg is absorbed by plants in the form of Mg +2. Due to its characteristics, the Mg absorption can be greatly affected by the availability of K +, NH 4 +, Ca 2+ and Mn 2+.
MAGNESIUM DEFICIENCY SYMPTOMS IN PLANTS
The symptoms are:
- Chlorosis of occurrence between the ribs, which progresses with intensity;
- Chlorosis in the shape of 'V' green inverted relative to the stem when in an advanced state;
- Reduced production;
- The reduced fruit size;
- Total acidity and vitamin C at lower levels.