Soil and Crops - An Introduction
Earth is made up of various elements that contribute to the whole ecosystem. The main elements of nature on which our survival depends are water, land, air, and soil.
Water is used for drinking purposes, land for habitats, air for oxygen, and soil for the consumption of food through agriculture.
Agriculture plays a very important role in the Indian Economy as it is the backbone of our country. Nearly 70% of the Indian population depends on agriculture for food and money.
In order to obtain sustainable food crops, it is very important to maintain the good quality of the soil. Soil plays a crucial role in providing nutrients to the plants, storing and filtering rainwater, providing water to various crops, and preventing pollution.
What is Soil?
Soil is the surface material composed of various organic matters, minerals, and microorganisms that is found on the uppermost layer of the earth’s crust.
They provide structural support to the plants that are used in the agricultural processes and are also the prime source of various nutrients, minerals, and water.
Soils differ in their chemical and physical properties depending on the climate and regions they are found in.
Each soil has unique properties which are favourable for various practices such as agriculture.
The physical characteristics of soil include texture, colour, structure, porosity, etc.
Types of Soils
There are different types of soil found in various parts of the country. They are as follows:
Black Cotton Soil
Laterite Soil
Mountainous or Forest Soil
Arid or Desert Soil
Alluvial Soil
Peaty and Marshy Soil
Saline and Alkaline Soil
What are Crops?
Crops are plants that are cultivated and harvested by the farmers during the agricultural process.
The cultivation of crops depends mainly on climate conditions and soil.
Types of Crops
There are different types of crops grown depending on the type of conditions and regions they are grown in.
Kharif Crops
These crops are grown in the monsoon season as they require a lot of water and hot weather for proper growth.
The seeds are sown at the beginning of the monsoon season and harvested later at the end of the season.
Examples include maize, cotton, millets, etc.
Rabi Crops
These crops are grown in the winter season. The word rabi means spring which is why the crops are later harvested in the spring season.
Examples include mustard, gram, and wheat.
Zaid Crops
Some crops' ideal conditions are different from different crops and require a warm climate for the germination and maturation of seeds but require a cold climate for growth.
These crops are grown between Kharif and Rabi seasons and are called Zaid Crops.
Examples - Watermelon, bitter gourd, pumpkin, and cucumber.
Cash Crops
The crops which are cultivated to be sold in the market to earn money are called cash crops.
These crops are sold in national and international markets.
Examples of cash crops are coffee, cotton, sugarcane, cocoa, etc.
Food Crops
The crops that are grown for consumption by the human population are called food crops.
There are a variety of food crops grown in our country.
Most of the staple food of the Indian population consists of food crops which are as follows:
Rice - It is a Kharif crop and the staple food of the majority of regions in the country. It requires heavy rainfall, high temperature, and humidity to assure proper growth.
Wheat - It is a rabi crop, the most important crop for the people in the north and north-western parts.
Pulses - India is known as the largest consumer and producer of pulses. Pulses can also be grown in dry conditions.
Millets - Millets include crops like jowar, bajra, and ragi. These crops are found in regions with continuous rainfall for a year.
Crops Grown in Different Types of Soil
Interesting Facts
Soil has the property of storing water beneath it and it is known that soil holds about 0.1% of the earth's soil.
There are three different layers of soil, mainly subsoil, topsoil, and the parent rock.
Important Questions
1. How many types of soil are found in India?
Ans: There are seven types of soil that are found in India; they are black Cotton Soil, Laterite Soil, Mountainous or Forest Soil, Arid or Desert Soil, Alluvial Soil, Peaty, and Marshy Soil, and Saline and Alkaline Soil
2. How is soil formed in nature?
Ans: Soil is formed by natural processes such as wind, temperature, and rain. The parent rock is first disintegrated and eroded by rains, followed by cracking and freezing and the top layer we will get is soil.
Key Features
Soil particles can be found in various sizes such as coarse, fine soil, grave soil, and clay soil.
Crops can also be used as a clothing material, as cotton cloths are made of cotton.
Crops are useful in many ways but they can also be used to control soil erosion.
FAQs on Soil and Crops - A Detailed Summary
1. What is a soil profile and what are its different layers or horizons?
A soil profile is a vertical cross-section of the soil from the ground surface downwards to the parent rock. It shows different layers, known as horizons, each with distinct characteristics. The main horizons are:
- O Horizon (Humus or Organic): The top layer, rich in organic matter like decomposing leaves and plants.
- A Horizon (Topsoil): A dark, fertile layer rich in humus and minerals, where most plant roots grow.
- B Horizon (Subsoil): Lighter in colour, with less humus but rich in minerals that have leached down from the topsoil.
- C Horizon (Parent Material): Made of small lumps of rocks and contains no organic matter.
- R Horizon (Bedrock): The solid, unweathered rock layer that lies beneath all other layers.
2. What are the main differences between sandy, clayey, and loamy soils?
The main differences between sandy, clayey, and loamy soils lie in their particle size, water retention, and aeration:
- Sandy Soil: Has large particles, large air spaces, and a low water-holding capacity. It feels gritty and does not hold nutrients well.
- Clayey Soil: Has very fine particles, small air spaces, and a high water-holding capacity. It is heavy and sticky when wet and becomes hard when dry.
- Loamy Soil: A mixture of sand, silt, and clay particles. It is considered the best for agriculture because it has a balanced water-holding capacity, good aeration, and is rich in humus.
3. Why is loamy soil considered the most suitable for growing a wide variety of crops?
Loamy soil is considered ideal for most crops because it offers the perfect balance of properties required for healthy plant growth. It contains a mix of sand, silt, and clay, which provides good water retention without becoming waterlogged, allows for proper aeration for roots, and is rich in humus and essential nutrients. This combination ensures that plants get a steady supply of water, air, and food.
4. How does soil erosion impact crop productivity and what are some effective methods to prevent it?
Soil erosion, the removal of the fertile topsoil by wind or water, severely impacts crop productivity by washing away essential nutrients and organic matter needed by plants. This leads to reduced soil fertility, lower crop yields, and can eventually turn fertile land into barren wasteland. Effective prevention methods include:
- Afforestation: Planting more trees, as their roots bind the soil particles together.
- Terrace Farming: Cutting steps into hillsides to slow down the flow of water.
- Contour Ploughing: Ploughing along the contours of a slope to prevent water from flowing straight down.
- Cover Crops: Planting grasses or other crops between main crop seasons to keep the soil covered and protected.
5. How does the percolation rate of soil affect the choice of crops planted in it?
The percolation rate, which is the speed at which water moves through the soil, is a critical factor for crop selection. Soil with a high percolation rate, like sandy soil, drains water quickly and is unsuitable for crops that need a lot of water, such as paddy rice. Conversely, soil with a low percolation rate, like clayey soil, retains water for longer periods, making it ideal for crops that thrive in moist conditions.
6. Why is black soil, known for its high clay content, particularly suitable for growing cotton?
Black soil, also known as regur soil, is ideal for growing cotton due to its unique properties. Its high clay content gives it an excellent water-holding capacity, which is crucial for the cotton plant's growth as it requires consistent moisture. Additionally, black soil is rich in essential nutrients like calcium carbonate, magnesium, potash, and lime. When it dries, it develops deep cracks, which helps in the deep aeration of the soil.
7. What is soil pollution and what are some of its main causes in agricultural fields?
Soil pollution is the contamination of soil with harmful substances that can negatively affect plant growth and human health. In agricultural fields, the main causes include:
- Excessive use of pesticides and herbicides: These chemicals can kill beneficial microorganisms in the soil and leave toxic residues.
- Overuse of chemical fertilisers: This can alter the soil's pH and contaminate both the soil and groundwater.
- Industrial waste and pollutants: Harmful chemicals dumped from factories can seep into nearby farm soils.
- Improper disposal of plastic and other non-biodegradable waste: This can harm the soil structure and prevent water absorption.
