With the recent rain and flooding that has occurred in the Eastern States of Australia recently, we have been thinking a lot about the tragic loss of topsoil. In some cases, people have lost most of their nutrient-dense, microbially rich growing medium (topsoil) which they lovingly nurtured for years. My heart goes out to these farmers and gardeners.
With this in mind, we decided to define a few common soil loss terms every gardener and agricultural producer should know and understand. Starting with Soil erosion:
What is soil erosion?
Soil erosion is a process that occurs when the impact of water or wind detaches and removes soil particles, usually washing fertile topsoil away into streams, rivers and oceans.
What causes soil erosion?
Soil erosion is caused by rainfall & flooding, heavy winds, agricultural practices, grazing, logging/mining and construction.
Effects of soil erosion:
Loss of arable land– soil erosion removes the top fertile layer of soil, this material is rich in nutrients required by plants and the soil. Degraded soil does not produce healthy plants/crops
Clogging of waterways -when agricultural soil contains pesticides, insecticides, fertilisers and other chemicals it pollutes local waterways and sediments accumulate in the water raising water levels resulting in flooding
Air pollution – dust particles from blown away soil merge in the air and cause widespread pollution. Pesticides and petroleum substances carried in the wind can be extremely hazardous when inhaled.
Desertification – occurs when once habitable regions are transformed into deserts due to soil loss. This leads to loss of biodiversity, further soil degradation and the alteration of ecosystems
Destruction of infrastructure – accumulation of soil sediments in dams and along embankments can reduce drainage and impact infrastructure projects.
What Is Soil Degradation?
Soil degradation is the physical, chemical and biological decline in soil health and quality, diminishing its capacity to support animals and plants. It results from improper land use from agriculture, pasture, urban and industrial purposes.
What is Soil Pollution?
Soil pollution is defined as the presence of toxic chemicals in soil, in high enough concentrations to cause harm. Common contaminants in soils are pesticides, petroleum products, raddon, asbestos, lead, chromated copper arsenate and creosote. Fossil fuels also contribute to soil contamination and water pollution.
Soil Salinity – Why is it a problem in Australia?
Soil salinity occurs when the water table rises, bringing natural salts to the surface, and at quantity, becoming toxic to plants. In Australia, dryland soil salinity (salinity on non-irrigated land) is our most costly form of land degradation. It is primarily caused by extensive land clearing and overgrazing from livestock.
Dryland salinity is defined as salinity at or near the soil surface causing reduced plant growth, reduced water quality and damage to infrastructure.
When European farming practices were implemented, many native deep root trees and shrubs were replaced with shallow-rooted crops and pastures that used less water and resulted in rising water tables causing dryland salinity. Soil salinity is a problem all over Australia, but especially south-west WA.
What can we do about it….
As explained above, human interference from the industrial age and beyond is responsible for most wide-spread soil loss. With climate change looking evitable, there is a widespread need to change current practice to prevent the impacts of soil erosion.
We need to nurture, cover and feed all valuable topsoil. Using biological fertiliser like Food2Soil along with complementary practices (for example no-till farming, using cover crops, mulching ground, avoiding chemicals etc) is the best way to protect vital topsoil that feeds human, animal and plant life. We simply can not function on this planet without soil.
