USES OF SOIL-SCIENCE BLOG

INTRODUCTION

Soil has several air spaces, water molecules and numerous biotic components like burrowing animals (earthworms, ants), microbes (fungi, bacteria)  winged worms (beetles, grasshoppers), and big animals (moles, rats ). Some organisms are very small, so we cannot see them in naked eyes. An important soil organism is an earthworm. We can see on the surface of soil only in the rainy season. It increases the uses of soil and the fertility of the soil.

WEATHERING IN USES OF SOIL

Rocks breakdown by the action of wind, water and climate into soil particles. We term this process weathering.  During this  phenomena , long duration of exposure to sunlight and rain , rock particles are broken down into small particles. Weathering is a very slow process as it takes thousands of years for a huge rock to turn into fine particles.  The parent rocks which form the soil makes the relevant habitat for the proper vegetation.

 SOIL PROFILE IN USES OF SOIL

Soil profile in uses of soil consists of different layer of soil which we term horizon. Each horizon differs in texture, color, depth and chemical composition.

A-HORIZON or TOP SOIL

It is the uppermost layer of soil above parent rock and usually dark in color because of the presence of minerals and humus in it. It  supplies the nutritive elements to the all plants through roots. Humus is the content of manure which is dark brown. Dead and decaying organic matter makes up the humus. Humus helps in making the topsoil porous.  A-horizon layer is not so hard. It can contain much amount of water. Many burrowing worms and animals make their home here.

 B-HORIZON  or SUBSOIL

This  is the second layer after the topsoil above the parent rock. It has little bigger rock and pebbles than the size of rocks in topsoil. It does not have much humus and is lighter in color than topsoil. This layer is harder due to lack of water, that is why the soil particles are compactly packed here. Subsoil is not so fertile like A-horizon. Very few biotic components can reside here. It contains minerals of iron and  other elements.

 C-HORIZON or SUBSTRATUM

The third layer under sub soil we term as C-horizon.  It has quite larger pebbles and stones. Uneven and larger rock particles use to accumulate here in uses of soil. This layer is emerged from bedrock or parent rock.

BEDROCK or PARENT ROCK

 The last layer of soil profile is bedrock also we term as parent rock. It contains uneven, bigger solid rocks which are not weathered. From this layer other horizons emerge. It has no air spaces, and it takes long time to form soil particles. Rain is sipping and uses to accumulate here to form ground water table.  Parent rock layer is very hard layer , so we use to have difficulties to dig out the ground water level from parent rock.

 SOIL TYPES IN USES OF SOIL

We classify soil according to the rock particles present in the soil and different proportions of sand, clay, and silt present in the uses of soilsoil.

ROCK PARTICLES PRESENT IN THE SOIL IN USES OF SOIL

According to the size of rock particles we divided the soil into following groups.

• CLAY:  These particles are very smooth in texture. It contains the smallest  stone particles which are like dust. So, we cannot differentiate them in bare eyes.
• Silt:  These are made up of bigger rock particle than clay. It is not so smooth as clay. River water deposits silts at river beds.  Rivers over flown during  floods, then deposited silt particles on the field.
• Sand :  The rock particles are quite larger in size. We can easily recognize each particles .  These particles are very harsh in texture as these are bigger in size.
•  Gravel: This layer has the unevenly larger rock particles usually parent rock.  Gravels contains small sized pebbles deposited on the topsoil.

 COMPOSITION OF SOIL IN USES OF SOIL

On the basis of composition of sand, clay and silt in soil , we can divide it into three parts.

• SANDY SOIL: These contain mainly sand. These are quite large particles. These are large spaces between them which is filled with air. Water can drain quickly through these spaces. This soil has a lots of air space, that is why it light weight and dry in texture. This soil is not sticky. We cannot make pots, bricks, toys and statues with this soil. Parent rock is loose.
• CLAYEY SOIL:  In this soil clay particles are very smaller and it does not provide any space. Because it’s packaging is very tight. Water drains very slowly through clayey soil. It contains very little humus. parent rock is sticky.
• LOAMY SOIL: It is a mixture of sand, clay and silt with small amount of humus in it. For this reason this soil provides  maximum nutrition for growing plants. It does not gather excess amount of water in it. Extra water is drained out. It is smooth  in texture, but sticky in nature. parent rock is smooth.

 CONCEPTUAL QUESTIONS ON USES OF SOIL OR PARENT ROCK

Qs1:  If a man starts to dig the soil, initially he can do the job easily, but gradually he goes to the deeper region, his work becomes difficult.  After 5 feet, he could not dig more. Provide a suitable scientific explanation.

Ans1: When the person starts to dig the pit from the topsoil and subsoil, he can easily do that job. Because these layer are mainly composed of humus and nutritive elements. But more he goes deeper in the soil layer , his work becomes more difficult beyond 5 feet  and more. After 5 feet depth, the layers contain small rocks, pebbles etc. These stones are having ridges and crevices. That is why we cannot dig the bedrock or parent rock easily.

 Qs2: In dense forests there is lesser erosion than that of barren field. Why?

Ans2: In dense forests, the tree cover or canopy prevents rainwater from directly falling on the ground. Plant roots can anchor the soil particles tightly so that these are bounded compactly. As a result, there is the reduction in soil erosion. Rain water directly falls on open soil. The rain water uses to flow soil particles as   soil of open field becomes  loose. By this process soil surface becomes eroded in uses of soil parent rock is exposed.

 Qs3: If the soils are repeatedly  water-logged, then plants can not grow properly. Why?

Ans3: Underground roots possess living cells which need oxygen for respiration and production of energy. They absorb oxygen which is present in the space between soil particles. But in the soil with water logging characters, water throws away oxygen into atmosphere. In this way, roots lack oxygen and this makes the plant growth stunted.