July 15, 2024




Citrus orchards, known for production of fruits like oranges, lemons, limes, and grapefruits, require specific soil conditions for optimal growth and fruit production. One critical aspect of soil health is the pH balance: if the soil becomes too acidic, it affects nutrient availability, root development, and overall plant health. One effective solution for managing soil acidity is the use of dolomite.

Dolomite is a naturally occurring mineral composed of calcium magnesium carbonate. It is often used as a soil amendment to raise the pH of acidic soils. Unlike calcium carbonate, dolomite provides the added benefit of magnesium, which is an essential nutrient for plants.


Soil pH and its importance in keeping soil healthy

Soil pH is a measure of the acidity or alkalinity of the soil, with a scale ranging from 0 to 14. A pH of 7 is neutral, below 7 is acidic, and above 7 is alkaline. For most citrus trees, the optimal soil pH ranges from 6.0 to 6.5. Within this range, nutrients are most available to plants, promoting healthy growth and high-quality fruit production.

 When soil pH falls below this range, it becomes too acidic, and results in:

  • Nutrient deficiency: Essential nutrients like nitrogen, phosphorus, and potassium become less available.
  • Toxicity: Elements like aluminium and manganese can become toxic to plants.
  • Diminished microbial activity: Beneficial microbial activity decreases, affecting soil health and fertility.

How dolomite works to improve soil

When dolomite is added to acidic soil, it undergoes a chemical reaction. The calcium carbonate and magnesium carbonate in dolomite react with hydrogen ions in the soil, which are responsible for acidity. This reaction forms water and carbon dioxide, effectively reducing the concentration of hydrogen ions and raising the soil pH. Calcium aids in cell wall structure and nutrient uptake, while magnesium is a core component of chlorophyll, necessary for photosynthesis.

  • Before applying dolomite, it's crucial to conduct a soil test to determine the current pH and nutrient levels. Soil tests provide information on how much dolomite is needed to achieve the desired pH balance.
  • Dolomite should be applied several months before planting new citrus trees or during the off-season for established orchards. This allows sufficient time for the dolomite to react with the soil and adjust the pH. Uniform distribution of dolomite is essential for effective pH adjustment. It can be spread using a broadcast spreader or similar equipment.
  • After applying dolomite, regular soil testing is essential to monitor pH levels and nutrient availability. This is because soil pH can fluctuate over time due to factors like irrigation, fertilisation, and organic matter decomposition.

Benefits of using dolomite in citrus orchards

Dolomitic Lime

Improved nutrient availability

By raising soil pH, dolomite enhances the availability of essential nutrients, promoting healthier and more productive citrus trees.

Enhanced root development

Optimal pH levels encourage robust root growth, improving the tree's ability to access water and nutrients from the soil.

Increased microbial activity

Beneficial soil microorganisms thrive in a balanced pH environment, contributing to soil health and fertility.

Magnesium supplementation

Dolomite provides magnesium, an essential nutrient that supports photosynthesis and overall plant health.

By understanding how dolomite works and implementing appropriate application practices, citrus growers can create an optimal environment for their trees, leading to improved yields and fruit quality. Through careful and informed use, dolomite presents a valuable tool in the quest for healthy, productive citrus trees and thriving orchards.

Bringing health back to Southern African soil

Lime Sales Ltd. is one of the leading producers and suppliers of dolomitic limestone products in the Western Cape. We supply dolomite and gypsum to the agricultural, construction and civil construction industries.


back to blogs