5. Soil degradation

Definition: Measurable loss or reduction of soil capability to produce desired plant material in quantity and quality.
Processes involved: Physical, chemical, and biological processes.
Causes: Natural (topography, climate) and human-induced (deforestation, pollution, mismanagement).
Impact of erosion in Asia: Productivity losses of 20% due to erosion in countries like India and China.
Soil Compaction: Can cause yield reductions of 25-50% in Europe and North America, and up to 90% in West Africa.

Physical Degradation: Compaction, sealing, erosion, desertification.
Chemical Degradation: Nutrient depletion, acidification, salinization.
Biological Degradation: Loss of biodiversity, destruction of soil structure.

Soil is a critical natural resource, necessary for sustaining plant, animal, and human life.
It provides food, regulates water, and supports economic development.
Soil must be protected from erosion and pollution; urban development should minimize environmental damage.

Definition: Soil's ability to supply essential nutrients for plant growth.
Plants require 14 nutrients in adequate forms; deficiency leads to poor growth.
Fertile soil can be poor if not properly managed; management can turn infertile soil productive.

Definition: Capacity of soil to yield optimum productions under specific management conditions.
Factors: Fertility, irrigation, and land management techniques.

Vital for sustaining productivity, enhancing water and air quality, and supporting biodiversity.
Soil is not merely a growing medium; it is a living system.

Measured by capacity to sustain ecosystem functions and productivity.
Quality Index Classifications: Better, Good, Moderate, Low, Very Low (0.80-0,19).

Characteristics: Formed in wetter regions; low fertility; mostly quartz, kaolinite.
Five suborders: Aquox, Perox, Torrox, Udox, Ustox.

Properties: Highly weathered, acidic soils in humid tropical and subtropical areas.
Five suborders focus on moisture regimes and organic matter content.

Deforestation: Leads to loss of organic matter, erosion, and reduced rainfall infiltration.
Shifting Cultivation: Involves clearing and burning of forests, causing soil degradation due to quick rotation cycles.
Soil Desurfacing: Removal of surface soil for construction and brickmaking reduces fertility.
Monocropping: Continuous planting of a single crop depletes soil nutrients.
Mismanagement of Irrigation: Can lead to salinization and reduced water availability.
Heavy Machinery: Compacts soil, disrupting structure and airflow.
Agrochemicals: Excessive use can introduce toxins and heavy metals.

Processes: Detachment and transport of soil particles by water, intensified by human actions like deforestation and overgrazing.
Types: Splash, sheet, rill, and gully erosion.
Control Measures: Use of cover crops, terracing, contour farming.

Occurs in dry, sparse vegetation areas leading to significant loss of topsoil.
Cause: Human actions such as deforestation and overgrazing exacerbate wind erosion.
Control: Vegetative barriers, cover crops, and management of crop residue.

Nutrient Depletion: Loss from continuous cropping without replacement.
Acidification: Affected by excess hydrogen ions; decreases pH.
Salinization: Salt accumulation from evaporation interferes with plant water intake.

Caused by the introduction of harmful substances, mainly from agriculture, industry, and waste disposal.
Main pollutants: Heavy metals, organic chemicals, pesticides, and sewage.
Control Methods: Bioremediation, chemical stabilization, soil washing.