The biosphere is the life-supporting zone of the earth. It consists of three sub-zones, namely lithosphere (rock, outermost layer), hydrosphere (water) and atmosphere (air). The soil is the natural resource which forms the lithosphere of the earth. It forms the crust, the outermost layer, of the earth. This layer is rich in minerals required by living organisms. Let us learn about soil formation, its significance and the minerals present in it and also about soil pollution and its consequences.
The soil is the fine particles that cover the outer layer of the earth. It is the abiotic component of an ecosystem. The soil is one of the factors that decide the types and diversity of living things in a habitat.
Formation and Factors Influence
The soil is formed from huge rocks and minerals. Over the thousands and millions of years, the rocks and minerals at the earth surface start to dissolve and break down. This results in the formation of the fine particles of soil. These rocks are called parent rocks and the process is called weathering. Weathering involves a series of events under the influence of various factors. Weathering of rocks includes physical, chemical as well as biological processes. Some of the factors that influence soil formation are as follows:
- Sun: The hot and cool atmosphere during day and night causes expansion and contraction of huge rocks. The uneven expansion and contraction eventually cracks the rock and thus weathering starts.
- Wind: A strong wind can carry small rocks and this will help one rock to strike against another. Continuous collisions wear down the rocks into smaller pieces. Winds also help to transfer soil from one place to another.
- Water: Water gets into the cracks in the rock. As the time passes, this will widen the cracks and break them further. Also, a heavy water flow carries smaller rocks which collide with other rocks, leading to erosion.
- Living organisms: Plants, algae, lichens, etc. are different organisms which take part in the soil formation. The chemicals produced by lichens as well as the growth and penetration of roots of trees into the cracks in the rocks, all these mince the rocks into soil.
Parent rock is rich in a variety of minerals; the above factors help to break the rocks. Thus, living organisms can use the dissolved mineral content in them.
Richness of Minerals
As air is a mixture of gases, a soil is a mixture of minerals and other matters. Soil may contain dead and decayed matter, microorganisms and other minerals which are useful for living organisms. All the organic matters like the dead and decayed content of the soil are called humus. This is a crucial factor that decides the fertility, texture and other characteristics of the soil. Based on the soil particle size, humus content and microorganisms present, the soil is divided into different types. The richness of minerals in a type of soil depends on the parent rock it was formed from.
As we know, the soil is vital for plants to thrive. The minerals and nutrients present, humus content, consistency, etc. are some important factors to be considered for cultivation. The top layer of soil contains minerals, humus, microorganisms and other particles. This topmost layer is called topsoil. Depending upon the topsoil, the biodiversity of a region also varies.
The soil is the backbone of agriculture. Since farmers started to use fertilizers and other chemicals for higher yields, it has spoiled the fertility of the soil. It contaminated the soil and this is called soil pollution. Soil pollution led to infertility by killing micro- and micro-organisms in the soil; the nutrient level has decreased. It also raised the number of barren lands. Deforestations caused soil erosion and soil got exposed to natural disasters. Thus, water and the wind take away the minerals and other contents of the soil.
Replenishment of nutrients in the soil by natural methods and organic farming are few solutions for recovering soil fertility. Reforestation and afforestation help to prevent soil erosions and loss of other valuable resources.
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