Soil Degradation

Why in news?

In a recent conference, UNESCO warns 90% of Earth’s land could be degraded by 2050.

What is soil degradation?

• Soil – A material composed of minerals, living organisms, soil organic matter, gas, and water.

• Soil degradation – It is the loss of the intrinsic physical, chemical, and/or biological qualities of soil either by natural or anthropic processes, which result in the diminution or annihilation of important ecosystem functions.

A third of the world’s soils are degraded and in India, around 29.7% land is degraded.

• Causes of soil degradation – The leading causes of soil deterioration are wind and water erosion, deforestation, and urbanization.
• Soil erosion – It is the displacement of the top layer of soil and is often caused by wind and water forces.
• Although these are naturally-occurring elements of nature, too much erosion can lead to soil depletion.
• Deforestation and overgrazing – Overgrazing and deforestation are the leading human activities that cause soil depletion.
• Urbanization – It creates mass amounts of pollution and less agricultural productivity, indirectly causing soil deterioration.

What are impacts of soil degradation?

• Loss of fertile soil – Degradation reduces the soil's ability to supply essential nutrients to plants, leading to decreased agricultural productivity.
  • World Atlas of Desertification – 75% of soils are already degraded, directly affecting 3.2 billion people.
• Lead to soil compaction - Heavy machinery, overgrazing, and deforestation can compact the soil, reducing its ability to hold water and air.
• Compacted soils have poor drainage and root penetration, which negatively impacts plant growth.
• Affects the health of living – The use of pesticides, herbicides, and industrial pollutants can contaminate the soil, affecting its health and the health of plants, animals, and humans that rely on it.
• Loss of soil inorganic carbon – This depletion could hurt the health of soil and its ability to regulate nutrient levels, foster plant growth and store carbon.
  • In India, soil acidification might lead to loss of 3.3 billion tonnes of soil inorganic carbon (SIC) from the top 0.3 metres of its soil over the next 30 years. 
• Depletes productivity – Acidic soils affect crop growth and productivity by reducing the availability of plant nutrients.
• Low pH levels (acidic soils) dissolves solid carbonate and removes it either as carbon dioxide gas or releases them directly into the water.
• It also predisposes plants to other biotic and abiotic stress factors.
• Threat to food security – Soil erosion and land degradation pose a major threat to global food security and to the achievement of the UN-mandated SDGs, compromising the well-being of at least 3.2 billion people around the world.
  • The loss of a few inches of topsoil has the potential to lower crop yields by 50%.

What lies ahead?

• Practice conservation tillage - Reducing the frequency and intensity of tillage helps preserve soil structure, reduces erosion, and maintains organic matter. Techniques such as no-till or minimum-till farming can be adopted.
• Cover crops - Planting cover crops during off-season periods helps protect the soil from erosion, improves soil structure, adds organic matter, and enhances nutrient cycling.
• Promote Agroforestry - Integrating trees and shrubs into agricultural landscapes provides multiple benefits, including improved soil structure, increased organic matter, reduced erosion, and enhanced biodiversity.
• Follow terracing and contour Farming - On sloped land, terracing and contour farming can reduce soil erosion by slowing down water runoff and promoting water infiltration.
• Enhance soil testing - Regular soil testing helps determine nutrient needs and prevent over-application of fertilizers.
• Control usage of fertilizers – Using balanced fertilization practices maintains soil fertility without causing pollution.
• Create awareness – The United Nations Food and Agricultural Organization (FAO) declared December 5 as ‘World Soil Day’.

References

1. Down To Earth| UNESCO Warns Accelerated Degrading of Earth’s Land
2. Down To Earth| Measures to Reduce Soil Degradation