Why do we need to worry about soil? Soil takes hundreds of years to form. Soil erosion (removal of soil) by wind or water is very fast. Humans are speeding up the process of soil erosion.
So how are humans destroying the soil? Over farming Use of chemicals Deforestation
Over farming In most places where farming takes place, people try to get as much profit as possible from as little land as possible. In order to achieve this they: o Farm the land every year, usually with the same crop. o This depletes the nutrients from the soil - the crops that use the nutrients are removed, and the nutrients are not replaced. o Result: The soil is left completely dried out – the amount of food that can be grown on it is reduced, and it can be easily blown away by wind, or carried away by water.
Use of Chemicals in Farming In order to deal with the depleted fertility of the soil, farmers are usually forced to use chemicals. In the long run, this has many negative consequences: The most commonly used chemicals are pesticides and herbicides. These kill the pests / weeds that compete with the crops for nutrients. Chemical fertilizers are also used to provide food for plants when the natural fertility of the soil is too low. Consequences: Chemicals seep into ground water and streams, affecting the entire environment. Many of plants and animals, as well as the people who come into contact with these chemicals, are harmed by this. The chemicals make the soil sterile, so that only one type of plant can survive.
Deforestation While forests in northern countries such as Canada are no longer being depleted, the more important tropical rainforests are being destroyed at a rapid pace! Why are tropical rainforests important? Biodiversity – they contain millions of species of plants and animals. They absorb carbon dioxide and give off oxygen (they reduce global warming).
The Amazon Rainforest This is the world’s largest tropical rainforest. It is located in South America.
The Amazon Rainforest This forest is being destroyed because Poor people are clearing it to make way for farms and ranches. Once it is cleared, the soil quickly becomes infertile and the farmers / ranchers must clear new land within a few years. Trees are also cut down because their wood can be sold. Roads have also been built through the forest to provide access to oil and mineral reserves.
Consequences of Deforestation Desertification Soil erosion Silting of lakes and rivers Floods Climate change (local and global) Drought