Question

After the soil is born how does it die?

Answer 1

Soil degradation is equivalent to death of soil. Soil erosion is the main factor for soil degradation and is due to several mechanisms: water erosion, wind erosion, chemical degradation and physical degradation.

Erosion is strongly related to human activity. For example, roads which increase impermeable surfaces lead to streaming and ground loss. Agriculture also accelerates soil erosion (increase of field size, correlated to hedges and ditches removal). Use of herbicides leaves the ground naked between each crop. New cultural practices, such as mechanization also increases the risks of erosion. Fertilization by mineral manures rather than organic manure gradually destructure the soil. Many scientists observed a gradual decrease of soil organic matter content in soils, as well as a decrease of soil biological activity (in particular, in relation to chemical uses). Deforestation is also responsible for degradation of forest soils.

Agriculture increases the risk of erosion through its disturbance of vegetation by way of:

1. Overgrazing of animals
2. Monoculture planting
3. Row cropping
4. Tilling or plowing
5. Crop removal
6. Land-use conversion