Correcting Magnesium Deficiency in Crops with Dolomite — Symptoms, Causes, and Treatment

Introduction

Magnesium is one of the most overlooked nutrients in crop production, yet it sits at the heart of every chlorophyll molecule — without it, plants literally cannot photosynthesise efficiently. Magnesium deficiency quietly caps yields across many soils, and dolomite is the classic, economical correction. This guide covers how to recognise magnesium deficiency, what causes it, and how to fix it with dolomite granules.

Why Magnesium Matters

Magnesium is an essential secondary nutrient with several critical roles:

• It is the central atom of chlorophyll — the molecule that captures light for photosynthesis.
• It activates many enzymes involved in energy transfer and metabolism.
• It supports the movement of phosphorus within the plant and helps in sugar formation and transport.

Because magnesium is central to photosynthesis, a shortage directly reduces the plant's ability to produce the sugars that build yield.

Recognising the Symptoms

Magnesium is mobile in the plant, so deficiency shows up in older, lower leaves first as the plant moves magnesium to new growth. The classic sign is:

• Interveinal chlorosis: yellowing *between* the leaf veins while the veins themselves stay green, giving a marbled or "herringbone" look.
• Progression from older to younger leaves as deficiency worsens.
• In some crops, reddish, purple, or bronze tints on older leaves.
• Reduced vigour, poor fruit fill, and lower yield in severe cases.

Because these symptoms can resemble other issues, confirm with a soil test and/or leaf tissue analysis before treating.

What Causes Magnesium Deficiency

Several conditions drive magnesium shortage: