Frangula alnus with magnesium deficiency

Frangula alnus with magnesium deficiency

© Karduelis

Type: Other


Magnesium deficiency

Magnesium is a key component of chlorophyll - the pigment which absorbs the energy from light (it also gives plants their green colour as green light is less well absorbed so this is what we see) to be used in photosynthesis. Affected plants will try to ensure that new leaves have enough chlorophyll so will move it from older leaves. Soil acidity (low pH) is the usual cause but the use of high potassium (potash) fertilisers also make magnesium unavailable to plants as it may be taken up in preference and nutrient-poor sandy soils may also suffer.

Symptoms

  • Yellow, orange, red or purple areas between leaf veins affect lower/older leaves first
  • These leaves may then turn brown and die
  • Reduced photosynthesis leads to stunted growth and lower yields

    • Prevention & control

      • Lime to raise soil pH
      • Reduce the use of high potash feeds
      • Build up organic matter (compost, manure, mulches) in lighter soils to help retain nutrients
      • Foliar feeding with Epson salts is the short-term solution
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