Question

mention briefly the stages of soil formation​

Answer 1

Answer:

The major points are: Soil forming factors interact to form the soil profile, including climate, topography, parent rock material and vegetation cover. Soil profiles may be formed by weathering or deposition processes. Parent material sitting on top of bedrock may be weathered to form part of the soil profile.

Answer 2

Accumulation of materials

Materials are added to the soil such as organic matter and decomposing materials or new mineral materials deposited by the forces of ice, water or wind and they accumulate over time. This happens in the top layer of the soil. In poorly drained soils, the organic materials accumulate since water-logging prevents it from being oxidized or broken down by soil organisms.

In well drained soils, the materials accumulate when they are held up by the root systems. Depositions by the forces of wind, water or ice equally contribute to the accumulation of new materials. Some plants with the help of bacteria fix atmospheric nitrogen and ammonia compounds into the soil as nitrates.

Leaching and losses

Through the movement of water, wind, ice or the uptake of the accumulated materials by plants, the new particles including clay, organic matter, clay, silt or other chemical compounds are leached and eroded away or taken up from the soil by plants. As a result, the physical and chemical compositions of the new accumulated materials together with the soil parent material are altered. A prime example is the leaching out of some carbonates, magnesium and other minerals.

Transformation and illluviation

Here the soil particles held in the suspension after the leaching such as clay are transformed after which they accumulate. Transformation is the chemical weathering of silt, sand, and the formation of clay minerals as well as the change of organic materials into decay resistant organic matter. After, the clay and other accumulated materials are washed from the upper horizons and deposited in the lower horizons. The plants and animals are also responsible for transformation of the soil by physically and chemically breaking down the materials. The soil begins to take shape on its own through transformation, which improves natural drainage and nutrient composition.

Podsolisation and translocations

Podsolisation takes place when strong acidic solutions breakdown the clay minerals. Accordingly, aluminum, silica and iron form complex materials together with organic compounds in the soil. These materials and the other accumulations are translocated within the profile and/or between the horizons. After a relatively extended time, the movements of the accumulated mineral precipitate such as iron oxides minerals are responsible for the reddish and brownish color of the different soil horizons.

The same applies to the alterations in structure, texture, and other mineral compositions. The soil horizons are then cemented by the carbonate, iron, and silica minerals. For instance, sandy soils are normally cemented by iron. Here, the soil drainage and air space will depend on the resultant soil type and the compaction and cementation process.