(RHIE) Human Impact- Erosion Lesson

Human Impact-Erosion 

Water, wind and gravity all play a part in the destructive process of erosion. Humans must deal with the result of changes in the land. Choices are made every day that will in some cases slow the process of erosion and other times will speed up the process of erosion.

Land and Soil

Soil is a non-renewable resource that once it is eroded it is not renewed.  Soil erosion is the permanent change of the main characteristics of soil that could see it lose its fertility, pH, colour, humus content or structure.  Soil erosion occurs naturally by wind or harsh climatic conditions but human activities cause erosion too, these activities include overgrazing, overcropping and deforestation.

You have learned that most of the Earth is covered in water. Less than a quarter of Earth's surface is dry land. Land is one of Earth's most precious natural resources. People need the land to produce their food, build shelter, and to obtain other resources. Humans use land in many ways. Humans change the land through agriculture, development, and mining.

Agriculture

Human activity causes ten times more soil erosion than all natural processes combined. Wilkinson, a scientist at the University of Michigan, warns us people can't find a way to stop stripping soil at the rate we are going now, nature will not be able to keep up. In geography and agriculture, arable land (from Latin arāre; "To plough, To farm") is land ploughed or tilled regularly, generally under a system of crop rotation.

Overgrazing

This happens when cattle ranchers, sheep farmers or other farmers of grazing animals have too many animals on their land. The animals cause damage to the soil by eating too much of the vegetation and digging into the wet soil or compacting the dry soil simply by walking over it with their hooves. The result of these actions prevent grass from growing and can slow water percolation through the soil. Nutrients are removed and the air between peds gets compressed out leaving damaged soil structure. Now the water between the soil gets compressed and less vegetation can grow. This will eventually leave the soil drier and susceptible to erosion by the wind and rain. Not just any soil, but rather the very important topsoil.

Overcropping

After a long, hard week of work your body and mind grows tired and you need to eat to replenish nutrients and you need to rest. The land needs time to replenish and to rest as well. Continuous cultivation of the land without allowing it to lie fallow between crops will result in overcropping. Constant farming of the land reduces the soils ability to produce valuable humus. Some farmers will attempt to restore fertility to soil by adding fertilizers or artificial nutrients.

Deforestation

When large area of forest are cut down leaving open, exposed landscape this is known as deforestation. Deforestation occurs for many reasons such as the sale of wood, charcoal or as a source of fuel, while cleared land is used as pasture for livestock, plantations of commodities, and settlements. Without sufficient reforestation the removal of trees can result in damage to habitat, biodiversity loss and drying of the soil. Natural erosion will be accelerated. Tree removal will remove the source of minerals and nutrients from the soil. Soil erosion will also happen faster because the exposed soil will easily be loosened when it rains heavily.

Development

Development includes any type of construction; homes, malls, stores, medical buildings, schools, office buildings, roads, bridges and any other type of structure. When people settle in an area they need shelter and access to goods and services. As population grows people expand across the land developing new areas to call home. Development can reduce the amount of available farmland and can destroy habitats wildlife depend upon. 

Low Impact Development and Green Infrastructure

Low Impact Development is primarily concerned with stormwater, you will learn about techniques to lessen the threat of stormwater damages as we read about the human impact on our natural resource; water. However, Low Impact Landscaping is sustainable landscaping that strives to create beauty with the lowest possible impact on the natural environment within which it exists, this type of landscaping design adds a strong emphasis on rainwater retention - preserving and enhancing the natural flow of water - to counteract the destructive water-wasteful practices humans have employed in the past.

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