Definition:
Soil degradation is the decline in soil quality and productivity, resulting in a loss of value and effectiveness for agricultural and ecological functions. It can stem from various anthropogenic and natural processes that adversely affect soil properties.

FORMS OF SOIL DEGRADATION

1. Physical Degradation
   • Causes:
     • Soil is physically destroyed through the impact of heavy rainfall and the use of machinery in agricultural practices.
   • Characteristics:
     • Poor Drainage: Soil compaction leads to reduced permeability, making it difficult for water to infiltrate.
     • Poor Porosity: Compacted soil has reduced pore spaces, limiting air and water movement.
     • Reduced Water-Holding Capacity: The ability of soil to retain moisture diminishes, adversely affecting plant growth.
2. Chemical Degradation
   • Causes:
     • Use of Agrochemicals: Overreliance on fertilizers and pesticides can lead to soil contamination and toxicity, impacting soil health.
     • Salination: The excessive use of chemical fertilizers may cause salinity, which depletes essential nutrients and reduces crop yields.

CAUSES OF SOIL DEGRADATION

• Deforestation: The removal of trees disrupts the natural cycle, leading to erosion and loss of organic matter.
• Bad Farming Practices: Unsustainable agricultural techniques, such as monocropping and over-tillage, contribute to soil degradation.
• Irrigation and Soil Drainage: Poorly managed irrigation practices can cause the accumulation of acids and salts, harming soil health.
• Leaching: Nutrient loss occurs when rainwater washes vital minerals deeper into the soil, making them unavailable to plants.
• Soil Compaction: Heavy machinery and excessive foot traffic compact the soil, reducing its ability to hold air and water.

EFFECTS OF SOIL DEGRADATION

• Soil Erosion: The removal of the topsoil layer, which is crucial for plant growth.
• Loss of Soil Fertility: Degraded soil becomes less capable of supporting crops due to nutrient depletion.
• Poor Soil Structure: Degradation leads to the breakdown of soil aggregates, affecting water infiltration and root growth.
• Flooding: Compacted and poorly draining soil increases runoff, leading to flooding in surrounding areas.
• Silting: Erosion can result in sediment deposition in rivers and lakes, harming aquatic ecosystems.
• Water Pollution: Chemicals from degraded soils can leach into water bodies, contaminating freshwater resources.
• Reduced Arable Land: The overall land area suitable for agriculture decreases, impacting food production.
• Spread of Weeds: Degraded conditions may promote the growth of invasive weed species, which compete with crops for resources.
• Loss of Fertile Topsoil: The uppermost layer of soil, which is rich in nutrients, is most vulnerable to erosion and degradation.

POPULATION AND SOIL DEGRADATION

• Demand for Wood Fuel: Increasing population leads to higher wood consumption, resulting in deforestation and habitat loss.
• Need for Shelter and Furniture: Urban expansion and construction activities contribute to land degradation and soil loss.
• Demand for Fiber: The cultivation of fiber crops like sisal and cotton can lead to soil depletion if not managed sustainably.
• Need for More Food: Growing populations drive the demand for food production, often leading to intensified agricultural practices that degrade soil.

WAYS TO CONTROL SOIL DEGRADATION

1. A) Biological Methods

• Planting Trees: Reforestation helps restore ecosystems, enhance soil stability, and improve water retention.
• Planting Cover Crops: These crops protect the soil surface, reduce erosion, and improve soil fertility.
• Grassed Waterways: Vegetation in waterways helps filter runoff and reduce erosion.
• Contour Farming: Farming along the contour lines of slopes minimizes soil loss and enhances water retention.
• Mulching: Applying organic materials on the soil surface retains moisture, suppresses weeds, and adds organic matter.

1. B) Physical Methods

• Stone Lines: Constructing lines of stones helps slow down water runoff and reduce erosion.
• Trash Lines: Heaps of crop residues can trap sediments, preventing soil loss and improving moisture retention.
• Ridging: Creating ridges enhances drainage and allows for better water absorption in crops.