Science, asked by chitta236, 8 months ago

The first step before growing crops is ____________ of the soil.
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Answers

Answered by balbirajumal123456
1

Answer:

preparation

Explanation:

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Answered by Anonymous
2

Answer:

preparation

(b) The first step before growing crop is preparation of soil. (c) Damaged seeds would float on top of water. (d) For growing crop, sufficient sunlight and water and nutrients from the soil are essential.

Explanation:

◉LET'S EXPLORE MORE

✯What is Soil?

Technically, the soil is a mixture that contains minerals, organic matter, and living organisms. But broadly speaking, soil can refer to any loose sediment. Moreover, there are many types of soil that are distributed around the world and these are generally classified into the following:

  • Clay Soil
  • Sandy soil
  • Loamy Soil
  • Silt Soil

Typically, the soil consists of 45% minerals, 50% empty spaces or voids and 5% organic matter. Furthermore, soil performs many important functions such as:

  • Providing a growth medium for the plants
  • Acts a modifier of the earth’s atmosphere
  • One of the most crucial components of the biosphere
  • Provides habitat for organisms

✯How is Soil Formed?

Soil is formed by weathering of rocks. Solid rock can weather away in one of the three ways into the soil, namely:

  • Mechanical Weathering
  • Chemical Weathering
  • Biological Weathering

☆Mechanical Weathering

This is commonly observed near the surface of the earth. Also called physical weathering, as this process is influenced by physical forces such as wind, water and temperature.

☆Chemical Weathering

As the name suggests, chemical weathering occurs when rocks are broken down by chemical reactions. Often, such types of weathering can change the chemical composition of the soil.

☆Biological Weathering

Though not an actual weathering process, living organisms weaken and subsequently disintegrate rocks, often by initiating mechanical or chemical weathering. For instance, tree roots can grow into cracks in the rock, prying them apart and causing mechanical fractures. Microorganisms can secrete chemicals that can increase the rock’s susceptibility to weathering

✯Horizons of the Soil

Soil consists of the following horizons:

☆1. Horizon A or Topsoil

It is also called the humus layer, which is rich in organic material. This layer consists of decomposed material and organic matter. This is the reason, the topsoil has a dark brown color. The hummus makes the topsoil soft, porous to hold enough air and water. In this layer, the seeds germinate and roots of the plants grow. Many living organisms like earthworms, millipedes, and centipedes, bacteria, and fungi are found in this layer of soil.

☆2. Horizon B or Subsoil

Just below the topsoil lies another layer called subsoil or horizon-B. It is comparatively harder and compact than topsoil. It is lighter in color than the topsoil because there is less humus in this layer. This layer is less organic but is rich in minerals brought down from the topsoil. It contains metal salts, especially iron oxide in a large proportion. Farmers often mix horizon-A and horizon-B when ploughing their fields.

☆3. Bedrock or Horizon C

Bedrock is also known as parent rock and lies just below the subsoil. It contains no organic matter and made up of stones and rocks, so it is very hard. This layer represents a transition zone between the earth’s bedrock and horizon A and B.

✯Composition of Soil

The soil is composed of different components: 5% organic matter, 45% minerals, 20-30% different gases and 20-30% water. Therefore, the soil is known as a heterogeneous body. Given below is the composition of soil in detail:

☆Organic Matter

Organic substance is found in very small amounts in the soil. Plants and animals are the main sources of organic matter. Depending upon the decomposition stage, the organic matter is of the following three types:

  • Completely decomposed organic matter
  • Partially decomposed organic matter
  • Undecomposed organic matter

☆Minerals

Minerals are an important element of the soil. These are solid components composed of atoms. These occur naturally and have a fixed chemical composition. Olivine and feldspar are the main minerals present in the soil.

☆Gaseous Components

The air-filled pores of the soil contain the gaseous components. Nitrogen and oxygen present in the pores is generally the atmospheric air fixed by the microorganisms. However, the composition of carbon dioxide is higher due to the gas produced by microorganisms present in the soil.

☆Water

The soil dissolves the minerals and nutrients in the water and transports it to different parts of the plants. These are essential for the growth and development of the plant.

✯Importance of Soil

Soil is an important element essential for the survival of living organisms. The importance of soil is mentioned below:

  • The fertile soil helps in the growth and development of the plants. The plants thus produced are healthy and provide food, clothing, furniture, and medicines.

  • It supports many life forms including bacteria, fungi, algae, etc. These microbes, in turn, maintain environmental balance by retaining the moisture and decaying the dead organisms.

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