The ground on which we walk is never quite the same, it keeps on changing. Sometimes it is made up of millions of tiny granules and other times it is the hard surface of tar covered roads. There was the time long back when this ground was mostly covered with soil and grass. And then came the roads, rails and so on. This soil is a very broad term and refers to a loose layer of earth that covers the surface of the planet.
The soil is the part of the earth’s surface which includes disintegrated rock, humus, inorganic and other organic materials that provides the medium for plants growth. For the formation of soil, it takes around hundreds to thousands of years. The soil is usually generated when rocks break up into their constituent parts. When a range of different forces acts on the rocks, they break into smaller parts to form the soil. These forces also include the impact of wind, water and the reaction from salts.
There are three stages of soil:
- Solid soil,
- Soil with air in the pores,
- Soil with water in the pores.
There are various types of soil that undergo diverse environmental pressures. The soil is mainly classified by its texture, proportions and different forms of organic and mineral compositions.
Types of Soil
The soil is basically classified into four types:
- Sandy soil.
- Silt Soil.
- Clay Soil.
- Loamy Soil.
The first type of soil is sand. It consists of small particles of weathered rock. Sandy soils are one of the poorest types of soil for growing plants because it has very low nutrients and poor in holding water, which makes it hard for the plant’s roots to absorb water. This type of soil is very good for the drainage system. Sandy soil is usually formed by the breakdown or fragmentation of rocks like granite, limestone, and quartz.
Silt, which is known to have much smaller particles compared to the sandy soil and is made up of rock and other mineral particles which are smaller than sand and larger than clay. It is the smooth and quite fine quality of the soil that holds water better than sand. Silt is easily transported by moving currents and it is mainly found near the river, lake, and other water bodies. The slit soil is more fertile compared to the other three types of soil. Therefore it is also used in agricultural practices to improve soil fertility.
Clay is the smallest particles amongst the other two types of soil. The particles in this soil are tightly packed together with each other with very little or no airspace. This soil has very good water storage qualities and making hard for moisture and air to penetrate into it. It is very sticky to the touch when wet, but smooth when dried. Clay is the densest and heaviest type of soil which do not drain well or provide space for plant roots to flourish.
Loam is the fourth type of soil. It is a combination of sand, silt, and clay such that the beneficial properties from each is included. For instance, it has the ability to retain moisture and nutrients, hence, it is more suitable for farming. This soil is also referred to as an agricultural soil as it includes an equilibrium of all three types of soil materials being sandy, clay, and silt and it also happens to have hummus. Apart from these, it also has higher calcium and pH levels because of its inorganic origins.
Important Questions and Answers about Soil
1. State the classifications of soil.
Soil can be classified into 3 primary types based on its texture – sand, silt and clay. However, the percentage of these can vary, resulting in more compound types of soil such as loamy sand, sandy clay, silty clay etc.
2. State the characteristics of sandy soil.
Sandy soil essentially consists of small particles formed by weathering rocks. It is also very low nutrients and poor in holding water, which makes it one of the poorest types of soil for agriculture.
3. Explain the significant features of a silty soil.
Silt has much smaller particles compared to sand. It is also made up of rock and other mineral particles. Furthermore, its fine quality holds water better than sand. Due to the above-mentioned features, it is also beneficial for agriculture.
4. Explain the characteristic of Clayey soil.
Clay contains the smallest particles amongst the other two types of soil. Particles are so densely packed that there is very little or no airspace. Consequently, this property effectively retains water. However, it also becomes hard for moisture and air to penetrate into it, thereby impeding the growth of plants.
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