Calcareous soils

Calcareous soils are a type of soil that is rich in calcium carbonate and often forms in areas with abundant limestone. They are common in many parts of the world, including the Mediterranean region, the Middle East, and parts of North America and Australia.

Formation

Calcareous soils form through the process of weathering, where rainwater that is slightly acidic dissolves the calcium carbonate in limestone and other rocks. This dissolved calcium carbonate is then transported to the surface by the movement of groundwater, where it precipitates out of solution and forms a layer of calcareous soil.

Characteristics

Calcareous soils are typically light in color, ranging from white to light brown, due to the high content of calcium carbonate. They are often shallow and stony, with a high drainage capacity. The pH of calcareous soils is usually neutral to slightly alkaline, which can limit the availability of certain nutrients such as iron and manganese.

Agriculture

Despite these limitations, calcareous soils are often highly productive for agriculture. The high calcium content can improve the structure of the soil, making it easier to work and promoting good root development. However, crops grown on calcareous soils may require additional fertilizer to supply nutrients that are less available due to the high pH.

Environmental Impact

Calcareous soils can have a significant impact on the environment. They can act as a natural buffer, reducing the impact of acid rain and other forms of acid deposition. However, the high calcium content can also lead to the formation of hardpan, a compacted layer of soil that can restrict water movement and root growth.

See Also

• Soil classification
• Soil pH
• Soil fertility
• Limestone