Types of soil - class-VII

The correct order of the increasing size of soil particle is-

Sandy soil has large particles with large spaces between them, allowing water to drain through very quickly, resulting in the poorest water-holding capacity.

The upper layer of earth in which plants grow, a black or dark brown material typically consisting of a mixture of organic remains, clay, and rock particles. It provides home to variety of microscopic and macroscopic organisms.

So, the correct option is 'All of these'. 

Salinization refers to the accumulation of water-soluble salts in the soil, which can negatively affect plant growth and soil fertility.

Desertification is the process by which fertile land becomes desert, typically as a result of drought, deforestation, or inappropriate agriculture.

Relative size of sand, silt and clay particles. Soil is made up of different-sized particles. Sand particles tend to be the biggest. 

Clay and silt soils tend to stick together, not allowing water and air to penetrate soil structure. They have poor soil porosity and do not let water drain. Aeration is poor and many plants decline and die in these non-porous, waterlogged soils. Poor porosity facilitates erosion of soils as rainwater washes particles off the surface rather than penetrating into soil. 

Clay soil particles are very small in size and packed tightly, water does not drain quickly, clayey soil is not well aerated and retains more water. Humus can easily mix or packed with clayey because of small particles also maintain the moisture in the soil and makes it more fertile. Thus, the answer is C.

Loamy soil is a mixture of various soil types. It has sand, silt and clay particles together. It has large air spaces inside it that allow free movement of air and water through it. 

Clayey and loamy soils are ideal for cereals like wheat and gram because they have good water-holding capacity and are rich in organic matter.

Clayey soil has very fine particles that pack tightly together, resulting in the smallest pore spaces and thus the least porosity.

Clay soil is soil that contains a high percentage of clay particles. It is slow to drain water and quick to harden holding the maximum amount of water and hence causing waterlogging. It blocks root absorption, which prevents plants from getting nutrients required for survival. Thus the correct answer is option C.

Loamy soil is the healthiest soil as it is a combination of minerals, rock, water and organic matter. Hence the soil contains microorganisms, insects, and worms that replenish soil fertility. Thus the correct answer is option C.

Clay soil particles are very small, packed very tightly and little space remain for air, water can be held in tiny space between the particles, so it has a good capacity to hold water. Thus, the correct option is C.

Loamy soil is a mixture of sand, clay and small types of other soil particles and the soil formed are known as silt. It is basically deposited on river beds. It is good for the growth of plants. Thus, the correct answer is D.

In humus, the percolation speed is very high. This means that more amount of substances are able to pass through it. Percolation rate is basically the rate at which the water moves through granular material. In humus, water moves very quickly. As a result, its percolation rate is very high.

Silts deposits on the river beds. Silts consist of fine sand, clay and other small stone particles which are carried by running or flood water, and deposited at the river beds. Thus, the correct option is A.

Clayey soil is used to make pots, toys and statues because the clayey soil has the highest water holding capacity than loamy, sandy and silt. Thus, the correct option is D.

Sandy soil is made of sand particles that are rough in texture. This prevents them from sticking tightly together. The space between sand particles is large for water to flow through it. Hence sandy soil drains faster than other types of soil. Thus the correct answer is option C.

Loamy soil is a mixture of clay, sand and silt. Particles of loamy soil are smaller than sand and larger than clay. Loamy soil has also a good water holding capacity and suitable for plants growth. Thus, the correct answer is D.

Water should percolate slowly in a soil because if water passes too rapidly, then many of the minerals and organic matter useful for plants will simply be washed away. If there is no percolation and all the water is simply held up in the soil, then there will be poor aeration and respiration in plant roots will suffer.

Sediment refers to solid fragments of inorganic or organic material, that comes from the weathering of rock and are carried and deposited by wind, water, or ice. Sedimentary soil is the transported soil, which is formed in this manner. Alluvial soil is the already formed soil, carried and deposited by flowing water as rivers etc.

Clay particles are defined as being less than 0.002 mm in diameter, distinguishing them from silt and sand.

Clay soil has the smallest particle size and the highest surface area, which results in very small pores. This structure restricts the movement of water and air, making it the least porous among the soil types listed.

Sandy loam is considered ideal for plant growth because it balances the drainage properties of sand with the nutrient and water-retention capabilities of clay and silt. Pure clay is often too waterlogged, while pure sand drains too quickly.

Soil particles are classified by size, with clay particles being the smallest (less than 0.002 mm). Silt particles are larger than clay, and sand particles are the largest among these categories.

Humus is the organic component of soil formed by the decomposition of leaves and other plant matter. It is vital because it provides essential nutrients and significantly improves the soil's ability to hold water.

Soil texture is defined by the relative proportions of sand, silt, and clay particles. While these particles influence water holding capacity, the term for the classification based on particle size is texture.

Clay soil has the smallest particles and the highest number of micropores, which allows it to retain the most water through capillary action. Sandy soil has large pores that allow water to drain quickly.

Soil can be classified on the basis of the size of the particle and its water holding capacity into clay soil, sand soil and loam soil, silt soil. Clay soil has the finest particles of all the soils. Hence, it is the least porous soil. Sand soil has the largest size of particles. They are the most porous soil.

Physiologically dry soil have very high concentration of salts. It is basicly dead soil from lack of oxygen and high salt content. The halophytes are plants of physically wet but physiologically dry habitats. Such plants are commonly found near sea-shores where mesophytes and freshwater hydrophytes cannot thrive well. Although these plants grow in the areas which are well saturated with water yet they cannot avail of the water because of high concentration of salts in the soils. 

A soil may be physically wet; but if the plants absorb the water only with difficulty, as in a salty marsh water logged soil, then the soil is physiologically dry. The halophytes are plants of physically wet but physiologically dry habitats. Such plants are commonly found near sea-shores where mesophytes and freshwater hydrophytes cannot thrive well. Although these plants grow in the areas which are well saturated with water yet they cannot avail of the water because of high concentration of salts in the soils. 

Clayey soil is found in various regions across India, including parts of Tamil Nadu, Jharkhand, and Odisha, depending on the local geological and weathering processes.