World Soil Day

Why are soils important?

Soils are important for various reasons, such as supporting plant growth, human nutrition, water filtration, and carbon sequestration. Soils also provide anchorage for roots, hold water and nutrients, and host diverse micro-organisms and animals. Healthy soils are essential for a resilient landscape that can cope with drought, flood, or fire.

What is soil?

Soil is the upper layer of the earth in which plants grow. It is a black or dark brown material typically consisting of a mixture of organic remains, clay, and rock particles.

How is soil formed?

Soil is formed through a combination of chemical, physical, and biological weathering. The process of soil formation involves the following steps:

1. Erode – Elements of weather cause the rocks, soil, and plant matter in an area to erode and become sediment that contains various minerals and nutrients that were in the previous materials.
2. Harden – The minerals harden over time to form deposits within the ground – these will later combine with other elements to create the final soil.

Did you know that soil takes several hundred years to form? The formation of 1 cm of soil takes at least 100 years.

What is a healthy soil?

Soil health is the condition of the soil to its inherent (or potential) capability, to sustain biological productivity, maintain environmental quality, and promote plant and animal health. Healthy soil is productive, sustainable, and profitable.

How can we protect soils?

We can protect soils by adopting sustainable land management practices, such as reducing tillage, planting cover crops, and rotating crops. These practices help to maintain soil health, reduce erosion, and improve soil structure and fertility. Additionally, we can use synthetic fertilizers, which can harm soil organisms and reduce the quality of soil, more efficiently.

Which role does soil play for water?

Soil plays a crucial role in the water cycle. It acts as a sponge, absorbing and storing water, and releasing it slowly over time. Soil also filters water, removing pollutants and impurities, and helps to recharge groundwater. Healthy soils are essential for maintaining water quality and quantity, and for mitigating the effects of floods and droughts.

Can you elaborate on this year’s theme “Soil and water: a source of life”?

The theme “Soil and water: a source of life” highlights the importance of soil and water for sustaining life on earth. Soil and water are essential resources that support plant growth, human nutrition, and ecosystem services such as clean air and water. Soil and water are also vital for mitigating the effects of climate change, reducing the risk of floods and droughts, and preserving the earth’s history and cultural heritage. This year’s theme emphasizes the need to protect and conserve soil and water resources for future generations.

Which role does soil play when it comes to civil engineering and agriculture?

Soil can be used in civil engineering to build structures (earthen structures) mainly for transport purposes or flooding protection. The mixing of lime with certain types of soil can improve their properties related to the construction needs making them suitable for use in civil engineering structure limiting or avoiding the transport and use of other soils with better qualities, their disposal and substitution, the use of other materials less sustainable as concrete or asphalt.

To preserve soil used for agriculture, farmers often rely on lime and minerals to balance the pH of the soil, maximize fertilizer efficiency, and improve their crops—our food—with calcium and magnesium. These specialized products also protect against heat stress and crop disease in organic agriculture.

Information based on interviews with Román Dobbe and Audrey Herbinet-Guénégan

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