Soil Degradation- Causes And Effects
Soil degradation refers to a decrease in soil quality caused by factors such as improper land use, agriculture, and pasture, as well as urban and industrial purposes. It entails the deterioration of the physical, biological, and chemical properties of the soil.
What are the Causes of Soil Degradation?
1. PHYSICAL FACTORS
• There are a number of physical factors that contribute to soil degradation, each of which is distinguished by how they alter the soil's natural composition and structure. Rainfall, surface runoff, floods, wind erosion, tillage, and mass movements all contribute to the loss of fertile topsoil, lowering soil quality.
• All of these physical factors cause various types of soil erosion (primarily water and wind erosion) and soil detachment actions, and the resulting physical forces change the soil's composition and structure by wearing away the top layer as well as organic matter.
• Physical forces and weathering processes cause soil fertility to decline over time, as well as adverse changes in the composition and structure of the soil.
2. BIOLOGICAL FACTORS
• Biological factors refer to human and plant activities that have the potential to degrade soil quality. Overgrowth of bacteria and fungi in a given area can have a significant impact on soil microbial activity via biochemical reactions, reducing crop yield and soil productivity capacity.
• Poor farming practices, for example, can deplete soil nutrients, resulting in a reduction in soil fertility. The biological factors have a major impact on the soil's microbial activity.
3. CHEMICAL FACTORS
• The chemical components of soil degradation include the loss of soil nutrients due to alkalinity or acidity, as well as water logging. In the broadest sense, it refers to changes in the chemical properties of the soil that influence nutrient availability.
• It is primarily caused by salt buildup and nutrient leaching, both of which degrade soil quality by causing undesirable changes in the essential chemical ingredients.
• These chemical factors cause irreversible loss of soil nutrients and productivity capacity, such as the hardening of iron and aluminum rich clay soils into hardpans.
4. DEFORESTATION
• Deforestation exposes soil minerals by removing trees and crop cover, which support the availability of humus and litter layers on the soil's surface, resulting in soil degradation. Because vegetation cover promotes soil binding and formation, its removal has a significant impact on the soil's aeration, water holding capacity, and biological activity.
• When trees are cut down for logging, infiltration rates increase, leaving the soil bare and vulnerable to erosion and toxic buildup. Logging and slash-and-burn techniques used by individuals who invade forest areas for farming, rendering the soils unproductive and less fertile in the end, are examples of contributing activities.
5. MISUSE OR EXCESS USE OF FERTILISERS
• Pesticides and chemical fertilizers are overused and misused, killing organisms that help bind the soil together. Most agricultural practices that involve the use of fertilizers and pesticides frequently involve misuse or overuse, resulting in the death of beneficial bacteria and other microorganisms that aid in soil formation.
• Denaturation of essential soil minerals occurs as a result of the complex forms of fertilizer chemicals, resulting in nutrient losses from the soil. As a result, fertilizer misuse or overuse accelerates soil degradation by destroying the biological activity of the soil and causing toxicities to build up as a result of improper fertilizer use.
6. Industrial and Mining activities
• Industrial and mining activities are the primary sources of soil pollution. Mining, for example, destroys crop cover and releases a slew of toxic chemicals like mercury into the soil, poisoning it and rendering it useless for any other purpose.
• On the other hand, industrial activities release toxic effluents and material wastes into the atmosphere, land, rivers, and ground water, which eventually pollute the soil and have an impact on soil quality.
• The physical, chemical, and biological properties of soil are all degraded as a result of industrial and mining activities.
7. Improper cultivation practises
• Certain agricultural practices are both environmentally unsustainable and the single largest contributor to the global decline in soil quality. One of the main factors is tillage on agricultural lands, which breaks up soil into finer particles, which increases erosion rates.
• The decline in soil quality is becoming more pronounced as a result of agricultural mechanization, which allows for deep ploughing, reduced plant cover, and the formation of the hardpan.
• Other improper cultivation practices, such as farming on a steep slope and mono-cropping, row-cropping, and surface irrigation, deplete the soil's natural composition and fertility, preventing it from regenerating.
8. Urbanization
• The impact of urbanization on soil degradation is significant. First and foremost, it depletes the vegetation cover of the soil, compacts the soil during construction, and changes the drainage pattern. Second, it covers the soil with an impermeable layer of concrete, which increases surface runoff and causes more erosion of the top soil.
• Again, most urban runoff and sediments are heavily contaminated with oil, fuel, and other chemicals. Increased runoff from urban areas also causes significant disruption to nearby watersheds by altering the rate and volume of water flowing through them, as well as depleting them with chemically polluted sediment deposits.
9. Overgrazing
• Overgrazing contributes significantly to soil erosion and the loss of soil nutrients as well as top soil. Overgrazing causes soil erosion by destroying surface crop cover and breaking down soil particles. As a result, soil quality and agricultural productivity have suffered significantly.
Effects of Soil Degradation
1. LAND DEGRADATION
• Soil degradation is one of the most common causes of land degradation, accounting for 84 percent of the world's shrinking land area. Huge swaths of land are lost each year due to soil erosion, contamination, and pollution.
• Erosion and the use of chemical fertilizers, which prevent land from regenerating, have severely harmed the quality of about 40% of the world's agricultural land.
• The degradation of soil quality caused by agricultural chemical fertilizers also leads to water and land pollution, lowering the value of land on the planet.
2. DROUGHT AND ARIDITY
• Drought and aridity are issues that are exacerbated and influenced by soil degradation. The UN recognizes that drought and aridity are anthropogenic induced factors, particularly as a result of soil degradation, as much as it is a concern associated with natural environments in arid and semi-arid areas.
• As a result, factors that contribute to soil quality decline, such as overgrazing, poor tillage methods, and deforestation, are also major contributors to desertification, which is characterized by droughts and arid conditions. In the same vein, soil degradation has the potential to reduce biodiversity.
3. LOSS OF ARABLE LAND
• Because soil degradation is linked to land degradation, it results in a significant loss of arable land. As previously stated, approximately 40% of the world's agricultural land is lost due to soil quality degradation caused by agrochemicals and soil erosion.
• The majority of crop production practices result in topsoil loss and damage to the natural soil composition that allows agriculture to exist.
4. INCREASED FLOODING
• When land loses its physical composition due to soil degradation, it is frequently altered from its natural landscape. As a result, the transformed land is unable to absorb water, causing flooding to become more common.
• To put it another way, soil degradation reduces the soil's natural ability to hold water, contributing to an increase in the number of cases of flooding.
5. POLLUTION AND CLOGGING OF WATERWAYS
• The majority of eroded soil, as well as chemical fertilizers and pesticides used in agricultural fields, are discharged into rivers and streams.
• The sedimentation process can clog waterways over time, leading to water scarcity.
• Agricultural fertilizers and pesticides also harm marine and freshwater ecosystems, limiting domestic water usage for populations who rely on them for survival.