Erosion forms many of Earth’s amazing features and can also pose serious problems, as soil being washed away may carry harmful chemicals into water sources and pollute the air.
Factors that lead to soil erosion include weather, topography, vegetation and tectonic activity. Deforestation, no-till farming practices and slash and burn practices are also major human causes that erode soil.
Weather
Rainfall is the primary factor influencing soil erosion. Heavy downpours tend to cause more erosion than light ones, particularly if there is no protection provided by vegetation or mulch covering the area in question. Permeability to water and composition also have an impact; compacted clay-rich soil will have less erosion potential.
Physical erosion, often brought on by swift rivers or streams, transports away rocks and soil fragments, leaving behind gullies, valleys and streambeds that create gullies or valleys; it may even result in landslides or mass wasting.
Plants can help prevent physical erosion by growing into and wedge-ing between cracks and crevices in rocks – this process is known as bioerosion. Liquid water and ice may contribute to physical erosion by seeping into cracks and crevices in rocks and expanding them, known as mechanical weathering or disaggregation. Furthermore, its freeze-thaw cycle may even fracture and fracture rocks into pieces called cryofracturing.
Vegetation
Plants cover the ground to help combat erosion by binding soil particles together and increasing permeability to rainwater, thus decreasing runoff rates. Vegetation also shields the soil from wind erosion rates – while severe winds or lack of cover increase them exponentially.
Erosion is a natural process that wears down landforms over time, yet can become an enormously destructive threat when it leads to poor crop yields, environmental degradation and desertification. Erosion also pollutes soil and sedimentation of waterways clogs rivers and poisons aquatic life including plants and animals that reside there.
Erosion may develop slowly over time and go undetected until large quantities of topsoil are lost. Heavy rainfall, gullies, and changes to soil texture are indicators that erosion is taking place, as are fine particles being carried away that reduce its ability to retain moisture, leading to drought or reduced crop production. But erosion can be controlled by planting trees, shrubs and grasses as living barriers against its spread.
Soil
Weathering breaks down rocks or soil into small particles that are carried away by erosion and deposited elsewhere. Although often unnoticed, erosion can have devastating consequences: its sediment can clog rivers and streams reducing their capacity for transporting water or waste, while at the same time carrying harmful chemicals into our drinking supplies and polluting them further.
Soil erosion is a global concern that reduces crop productivity and soil quality while destabilizing natural landscapes. Encourage your students to identify major landscapes formed by erosion and ask how these were formed; discuss this topic as a class. Common causes include intense agriculture, deforestation, roads, climate change and urbanization – students can reduce this threat by planting grasses that form deep roots that cover most of the ground throughout the year – this will protect it against rainfall or wind erosion.
Water
Water erosion refers to the movement of liquid through soil particles, typically as rain or river flow. This process can have catastrophic effects for agricultural land as well as buildings and roads, transporting agricultural chemicals into watercourses which subsequently pollute drinking water supplies, as well as pollute drinking water sources with agricultural chemicals that pollute drinking water supplies.
Physical erosion refers to rocks undergoing changes without altering their basic chemical makeup, leading them to either become smaller and smoother or accumulate sediments such as sand and gravel on their surfaces. Physical erosion is often one of the major contributors to landslides or mass wasting events.
Intensive agriculture, deforestation, roads, acid rains and climate change all play a role in increasing erosion rates. Erosion causes land degradation which in turn reduces fertility as plants struggle to take in enough carbon dioxide from the air; further contributing to global warming. Erosion also leads to movement of material off site which contributes to sedimentation of rivers or lakes or contamination of drinking water sources.