Land degradation is a concept in which the value of the biophysical environment is affected by one or more combinations of human-induced processes acting upon the land. It is any change or disturbance to the land perceived to be deleterious or undesirable.
Soil erosion is but one of the physical indicators of land degradation occurrence. Erosion is the process of weathering and transport of solids (sediment, soil, rock and other particles) in the natural environment or their source and deposits them elsewhere. It usually occurs due to transport by wind, water, or ice; by down-slope creep of soil and other material under the force of gravity; or by living organisms, such as burrowing animals, in the case of bio-erosion.
Erosion is a natural process, but it has been increased dramatically by human land use, especially industrial agriculture, deforestation and urban sprawl. Land that is used for industrial agriculture generally experiences a significantly greater rate of erosion than that of land under natural vegetation, or land used for sustainable agricultural practices. This is particularly true if tillage is used, which reduces vegetation cover on the surface of the soil and disturbs both soil structure and plant roots that would otherwise hold the soil in place.
However, improved land use practices can limit erosion, using techniques such as terrace-building, conservation tillage practices and tree planting. Climate change predictions are that there will be an increase in the average and peak wind speeds experienced in our region. This could substantially escalate wind erosion and airborne dust generation, thus the potential for significant wind erosion hazards in the future will increase which will make good farming practices even more valuable.
Land degradation is a global problem, largely related to agricultural use. The major causes of human activities include:
- Land clearance, such as clear-cutting and deforestation
- Agricultural depletion of soil nutrients through poor farming practices
- Livestock including overgrazing
- Inappropriate irrigation and over-drafting
- Urban sprawl and commercial development
- Land pollution including industrial waste
- Vehicle off-roading
- Quarrying of stone, sand, ore and minerals
Land degradation can indirectly affect phenomena such as floods and wildfires, which may in turn have a more severe impact on life and property.
By drafting your own Family Emergency Plan and identifying all your risks, including those hazards affecting your own environment, you can make a positive contribution to preparedness.