Soil

Forest is a place where plenty of trees and plants are grown. Due to plants and trees, nutrients and moisture are sufficient. This promotes growth of microorganisms.

The A-horizon layer of the soil is soft, porous and retains water. The roots of small plants are grow in this layer. This layer is also called topsoil.

Soil conservation is a measure of protecting topsoil from depletion by wind and water. Topsoil is rich in humus and nutrients which supports plant growth.

Statements (ii) and (iv) are correct. Options (i) and (iii) are wrong. (i) Weathering is a slow process of soil formation and (iii) loamy soil consists of sand, clay and silt along with humus.

The increasing order of soil particles is given below:

Smallest Largest

Clay < Silt < Gravel < Sand < Rock,

sand, clay and slit

Loamy soil is a mixture of sand, clay and silt. Besides these particles, the loamy soil contains humus in it. This soil has good water holding capacity for the growth of plants.

(a) Weathering: The process of breaking down of rocks by the action of wind, water and climate.

(b) Soil erosion: A process of depletion of top soil.

(c) Humus: The rotting dead matter in the soil.

(d) Percolation: Seepage of water into the soil.

(a) Humus: The rotting dead matter in the soil.

(b) Soil profile: A vertical section through different layers of the soil. (c) Horizon: Layers of the soil differs in texture colour, depth and chemical composition. These layers are referred to as horizons.

(d) Loam: Loam is a soil made of sand, clay, silt and humus. .

(e) Weathering: The process of breaking down of rocks by the action of wind, water and climate.

(f) Percolation: The process of movement of water into deeper layers of soil.

Situation ‘B’ is beneficial for the plants growth because A-horizon is the top layer of the soil and Horizon B is the subsoil, next to A. Both of these layers are rich in water, minerals and humus.

By adding a small quantify of quicklime or slaked lime in the soil, farmers can convert acidic soil to neutral soil. Quick lime is basic in nature and it neutralises acid of the soil. Therefore, acidic soil is converted to neutral soil.

In my opinion, it is not a good practice. Small plants and grasses cover the soil surface and their roots hold the soil particles together. These plants prevent soil erosion (removal of top soil) during strong winds and heavy rains. Thus, Small plants and grasses protect the top soil.

It is easier to dig soil initially because the upper layer of the soil consists of topsoil and subsoil. These two horizons are composed of loose soil particles and easy to dig. At the deeper layers, partially weathered rocks or bedrocks are present. It is very difficult to dig through partially weathered rocks or bedrocks.

A desert is a very large area that covered with sand or rocks. Since desert has sandy soil where rain water quickly seeps (percolates) into the sandy soil. Due to this reason Boojho did not see streams of water in the desert region.

Different living organisms such as earthworm, rodents (rats), crabs, lizards live in the different layers of the soil. From the soil these organisms get nutrition.

The function of the roots includes water absorption and uptake of oxygen from the pore space (the space between soil particles) of the soil. When soil is water logged, all the pore spaces are filled with water and oxygen is pushed out of the soil. Oxygen from the pore spaces move into the atmosphere. So, in water logged soil, the plants do not grow well as the roots of the plants do not absorb oxygen. This stops the respiration and production of energy. As a result the plant dies after some time in absence of oxygen.

Very large numbers of trees are grown in the dense forest. The trees have large number of leaves covering the ground. Even very less amount sunlight reaches to the ground. The leaves covering prevents rain water from directly falling on the ground. Besides roots of the trees bind the soil particles and hold them together. As a result soil erosion is minimised.

But in barren, open fields the soil is directly exposed to the falling rain. The soil particles become loose with the effects of the rain water. The water that carries away the soil causes erosion. Further the flowing water erodes the soil surface increases the amount of soil erosion.

The gardener gently digs up soil around the root for the following reasons:

(a) Digging soil removes weeds

(b) Makes easy for water to percolates into the soil. Digging loosen the soil

(b) It Promotes root growth;

(c) It increases the pore spaces of the soil enabling air to get into deeper layers of soil;

In towns and cities the bore wells have to be dug very deep to get water because in town and cities water is used excessively, which depletes the ground water. Secondly, in towns and cities roads are made of asphalt and vast areas of soil are concreted. As a result, rain water cannot percolate. Therefore, depleted ground water is not replaced. As a result ground water level further decrease. But in villages vast areas are open and soil surface and have fewer asphalted roads and concrete surfaces. Thus, larger soil surface area is available for rain water to percolate into the soil easily and recharge the ground water. As a result, even shallow bore wells yield water.

The terms related to the soil hidden in the square are: Humus, Sand, Water, Clay, Gravel, Weathering, Horizon, Percolation, Mineral, Plant, Erosion, and Profile