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Nutrient Benefits


High Mg levels can reduce the availability of:

  • Potassium


Increased Mg levels can create a demand for more:

  • Phosphorus
  • Nitrogen


  • The center molecule of the chlorophyll
  • Aids several functions of different plant enzymes
  • Aids plant to form sugar and starches
  • Plays an important part of the translocation of P

Deficiency Symptoms

  • Interveinal chlorosis beginning in the tops of older leaves. Veins remain green, while the chlorotic areas turn yellow to brown (other colours in some plants)
  • Leaves become brittle and necrotic and may drop prematurely
  • Yield may be seriously reduced
  • Cotton leaves develop a purplish red colour between veins
  • Some varieties of black grapes and stone and pit fruit can develop interveinal red chlorotic areas

Factors Affecting Availability

  • Sandy, acidic soils, particularly in high rainfall areas
  • Coarse textured soils in humid regions
  • Cold, wet conditions
  • Soils where there has been heavy inputs of K
  • Soils which have received repeated manuring
  • Severe defoliation of terminal shoots progressing from base to tip

Sensitive Crops

Vines, pome fruit, stone fruit, citrus, tomatoes, capsicums, broccoli, cauliflower, lettuce, potatoes, parsley, pumpkin, cereals, oilseeds, corn, and other root crops


The following OMEX products can assist with addressing and correcting Magnesium deficiency:

Visual Guide