Soil Layering or Stratification

It takes about 1,000 years for a 25mm layer of soil to develop. During the formation of soil, soil particles are separated and accumulate at various depths. Soils are also carried and deposited by water and wind to form soil layers with different soil properties.

The soil layers have an influence on the potential of the soil. If the properties, especially the texture, of the two underlying soil layers differ too much, plant roots will not grow into the next layer. Similarly, water will not penetrate the second layer, but rather flow away along with the merger of the two layers. A simple way to determine if layering could be a problem is by determining the texture of both layers. If the texture differs by more than 50%, the layer will cause a problem. If, for example, the topsoil contains 20% clay and the next layer more than 30% (50% of 20 = 10%), the stratification of the soil is too severe and will impede root growth and water movement.