Mineral Riches in Soil: Formation, Types and Functions

Ans: Different chemical elements in soils from soil mineral riches. They are nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, iron, manganese, molybdenum, etc and their compounds. All these mineral elements, their free ions, and compounds form soil mineral riches.

These mineral nutrients in the available forms are very important for the growth and development of plants. Vegetative growth, flower formation, and fruit formations depend on these essential elements. Without these elements, plants cannot complete their life cycles.

Ans: The topmost layer of the earth crust is called soil. The earth’s crust consists of rocks with chemical compounds in different proportions. Due to the influence of wind, water, and biological agents, these rocks are disintegrated into simpler compounds or elements. The process of disintegration of rocks is called weathering.

Soil is formed due to physical, chemical and biological factors. Sunlight supplies heat to rocks. Rocks expand during the daytime and contract during night-time. So, rocks develop cracks. Water freezes in gaps to widen the gap in rock crevices. The roots of plants exert pressure in gaps. Carbon dioxide from roots forms carbonic acid after being combined with water. Carbonic acid and humic acid in organic matter further make soil particles finer.

Ans: Essential elements in soil form soil mineral riches. Soil mineral riches are classified as primary minerals and secondary minerals based on their origin.

Soil mineral riches that have been in the existing form since their formation from parent rocks are called primary minerals. Some of the primary minerals in soil mineral riches consist of crystalline minerals like siliceous minerals, silicates, apatite, ferrous minerals, titanomagnetite, volcanic gases and non-crystalline minerals.

Soil mineral riches that have been in a chemically different form since their formation from parent rocks are called secondary minerals. Due to an increase in the surface area, these particles retain a lot of soil moisture. Fine silt and clay particles especially have this kind of soil mineral riches. Some of the important secondary minerals in the soil mineral riches are carbonates, halides, hydroxides, oxides, phosphates, phyllosilicates, and sulphates.

Ans: Chemical constituents of soil are called soil minerals. They are different types like

1. Calcite: It is a colourless or white mineral substance. It is a major component of sedimentary rocks that are formed from calcium carbonate.
2. Dolomite: It is calcium-magnesium carbonate. It is a chief source of magnesium in different soils.
3. Gibbsite: Chemically it is aluminium hydroxide. It is also called hydrargillite. It is an important aluminium ore in soils.
4. Gypsum: It is a soft calcium sulphate dehydrate mineral. It is found in sedimentary rocks and is water-soluble.
5. Hematite: It is a hydrated iron mineral. It is red to blackish-red in tint and swells upon absorbing water.

Ans: Essential chemical elements in the soil form soil mineral riches. Their important functions are,

1. Soil mineral riches form the basic structural and chemical composition of the soil.
2. The soil texture is decided by the relative sizes of the soil particles and minerals in them.
3. The structure of soil mineral riches decides the feasibility of cultivation.
4. Different ions in soil mineral riches are a source of nutrition for the growth and development of plants.
5. The presence of essential elements in the soil is very important for the cultivation of different crops.

Ans: Minerals present in soil are called mineral riches in the soil. Minerals that are required for the growth and development of plants are called essential elements. Soil minerals without any change in their properties are called primary minerals. Soil minerals with changes in their chemical properties are called secondary minerals. There are different soil-forming minerals like calcite, dolomite, gypsum, hematite, etc. Different ions in soil mineral riches are a source of nutrition for the growth and development of plants.

Ans: The disintegration of parent rocks into soil particles is called weathering. Weathering of rocks occurs due to physical, chemical and biological factors. Mineral elements in rocks are in an unavailable form. Weathering makes these elements available in molecular, and ionic forms. These tiny compounds get mixed with soil solution. When plants absorb water, these mineral elements will also enter the plant body. Likewise, weathering helps plants absorb various essential elements in available forms.

Ans. The major factors of soil formation are the nature of the parent rock and climatic factors.

1. Parent Rock: Determines colour, texture, chemical properties minerals, content, permeability.
2. Climate: Temperature, rainfall influence the rate of weathering and humus.
3. Relief: Altitude and slope, determine the accumulation of soil.
4. Flora, Fauna and Microorganism: Affect the rate of humus formation.
5. Time: Determines thickness of soil profile.

Ans. Some broad mitigation techniques of landslide are as follows:

1. Hazard mapping for locating landslides prone areas, so that building settlements can be avoided.
2. Construction of a retention wall to stop the land from slipping.
3. Increase in the vegetation cover to arrest landslides.
4. The surface drainage control works to control the movement of landslides along with rainwater and spring flows.

Ans. Following are the six types of soil found in India:

1. Red soil
2. Black soil
3. Alluvial soil
4. Desert soil
5. Mountain soil
6. Laterite soil