Question

NCERT solution for class 8 science chapter 1 crop and management note



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Answer 1

Answer:

Select the correct word from the following list and fill in the blanks.

float, water, crop, nutrients, preparation

(a) The same kind of plants grown and cultivated on a large scale at a place is called _____

(b) The first step before growing crops is _______ of the soil.

(c) Damaged seeds would ______ on top of the water.

(d) For growing a crop, sufficient sunlight and ______ and ______ from the soil are essential.

Answer:

(a) crop

(b) preparation

(c) float

(d) water, nutrients

Question 2.

Match items in column A with those in column B.

A B

(i) Kharif crops (a) Food for cattle

(ii) Rabi crops (b) Urea and superphosphate

(iii) Chemical fertilisers (c) Animal excreta, cow dung, urine and plant waste

(iv) Organic manure (d) Wheat, gram, pea

(e) Paddy and maize

Answer:

(i) (e)

(ii) (d)

(iii) (b)

(iv) (c)

Give two examples of each.

(a) Kharif crop

(b) Rabi crop

Answer:

(a) Kharif crop: Paddy and maize

(b) Rabi crop: Wheat and gram

Question 4.

Write a paragraph in your own words on each of the following.

(a) Preparation of soil

(b) Sowing

(c) Weeding

(d) Threshing

Answer:

(a) Preparation of soil: Soil preparation is necessary before growing a crop. It involves tilling and loosening the soil. This allows the roots to penetrate deep in the soil and to breath easily even when they are deep.

(b) Sowing: The process of putting seeds into the soil is called sowing. The tool used traditionally for sowing seeds is funnel-shaped. Nowadays a seed drill is used for sowing with the help of tractors. This tool sows the seed uniformly at a proper distance and depth.

(c) Weeding: Some undesirable plants grow along with crop and these unwanted plants are called weeds. The process of removing these unwanted plants is called weeding.

(d) Threshing: The process of separating the grain seeds from the chaff is called threshing.

Question 5.

Explain how fertilisers are different from manure.

Answer:

Fertilisers Manures

(i) A fertiliser is an inorganic salt. (i) Manure is a natural substance obtained by the decomposition of cattle dung, human waste and plant residues.

(ii) A fertiliser is prepared in factories. (ii) Manure can be prepared in the fields.

(iii) A fertiliser does not provide any humus to the soil. (iii) Manure provides a lot of humus to the soil.

(iv) Fertilisers are very rich in plant nutrients like nitrogen, phosphorus and potassium. (iv) Manure is relatively less rich in plant nutrients

Question 6.

What is irrigation? Describe two methods of irrigation which conserve water.

Answer:

The artificial method of watering the plants for assisting in their growth is called irrigation. Main sources of irrigation are wells, tube-wells, ponds, lakes, rivers.

Two methods which help us to conserve water are:

(i) Sprinkler irrigation system: This irrigation system has an arrangement of vertical pipes with rotating nozzles on the top. It is more useful in the uneven and sandy land where sufficient water is not available.

(ii) Drip irrigation system: This irrigation system has an arrangement of pipes or tubes with very small holes in them to water plants drop by drop just at the base of the root. It is very efficient as water is not wasted at all.

Question 7.

If wheat is sown in the kharif season, what would happen? Discuss.

Answer:

Wheat crop is sown from November/December to March/April. It is grown in winter and requires less water. If wheat is sown in Kharif season, its production will be decreased considerably.

Question 8.

Explain how soil gets affected by the continuous plantation of crops in a field.

Answer:

Continuous plantation of crops makes the soil poorer in certain nutrients as the crops take up nutrients from the soil. The soil becomes infertile. It does not get enough time to replenish the nutrients.

What are the weeds? How can we control them?

Answer:

The undesirable and unwanted plants which grow naturally along with the crop are called weeds. The growth of weeds can be controlled by adopting many ways. Tilling before sowing of crops helps in the uprooting and killing of weeds, which may then dry up and get mixed with the soil. Weeds are also controlled by using certain chemicals, called weedicides. Weedicides are sprayed in the fields to kill the weeds.

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Answer 2

NCERT Class 8 Science Notes Chapter 1 Crop Production and Management.

We already know that:

• All living organisms require food.
• The energy from food is utilized by an organism for carrying out its various life processes such as digestion, respiration and excretion.
• Plants can make their food themselves but animals including humans cannot.
• We get our food from plants or animals, or both.

In our country three categories of crops are grown:

• Kharif Crops: The crops which are grown in the rainy season (i.e., from June to September) are called Kharif crops. Paddy, maize, soybean, groundnut, and cotton are Kharif crops.
• Rabi Crops: The crops are grown in the winter season (i.e., from October to March) are called rabi crops. Examples of rabi crops are wheat, gram, pea, mustard, and linseed.
• Zaid Crops (or Summer Crops): The crops grown in the summer season are ( called zaid crops). Moong, muskmelon, watermelon, cucumber, gourd and bitter gourd are examples of zaid crops.

Cultivation of crops involves the following activities:

• Soil Preparation: It involves loosening and tilling of the soil (i.e., ploughing and watering).
• Sowing: Sowing is the process of putting seeds in the soil.
• Adding Manure and Fertilizers: The substances, which are added to the soil in the form of nutrients to improve the production of the crops and fertility of the soil are called manure and fertilizers.
• Irrigation: Supply of water to crops at appropriate intervals is called irrigation.
• Protection from Weeds: Weeds are the unwanted plants that grow along with the crops. Its removal is a must for the better growth of the crops. These can be controlled by spraying certain chemicals, called weedicides, like 2, 4-D.
• Harvesting: The cutting of the crop after it is mature is called harvesting.
• Storage: If the crop grains are to be kept for a longer time, they should be safe from moisture, insects and rats.

Humus: Humus is the top layer of the soil formed by decaying or decomposition of organic matters like animal remains, shed leaves, the dung of cattle.

Pests: Pests are the insects or rodents that destroy much of our crop yield. Thus, it is necessary to save crops from pests.

Important agricultural tools:

• Plough: This is used for tilling the soil, adding fertilizers to the crop, removing the weeds, scraping of soil, etc. This implement is made of wood and drawn by a pair of bulls.
• Hoe: It is used for removing weeds and for loosening the soil.
• Cultivator: Used for ploughing. It is driven by a tractor. Use of cultivator saves labour and time.
• Traditional Tool: The tool used traditionally for sowing seeds is shaped like a funnel.
• Seed Drill: Used for sowing with the help of tractors. This tool shows the seeds uniformly at a proper distance and depth.
• Sickle: Used for manual harvesting.

Food from Animals: Like plants, the animals also provide us with different kinds of food like fish, meat and eggs.

Fumigation: Fumigation is the most effective method for checking the growth of insects by providing smoke or chemicals in the gaseous state without affecting the grain.

Agricultural practices: There are various activities that have to be performed, before sowing and up to harvesting. These are called agricultural practices.

Animal husbandry: Animals reared at home or on a farm, have to be provided with proper food, shelter and care, when this is done on a large scale it is called animal husbandry.

Crop: When plants of the same kind are grown at a place in a regular manner on a large scale, it is called a crop.

Fertilizer: Fertilizers are chemicals which are rich in a particular nutrient like nitrogen, phosphorus and potassium.

Granaries: The harvested grains, usually are stored in huge stores, after they are’ properly dried in sunlight. Such stores are called granaries.

Harvesting: The cutting of the crop after it is mature is called harvesting.

Irrigation: Supply of water to crops at appropriate intervals is called irrigation.

Kharif Crops: The crops which are grown in the rainy season, that is from June to September are called kharif crops.

Manure: Manures are decomposed organic matter obtained from plant or animal waste.

Plough: The device used for tilling or ploughing is called plough.

Rabi Crops: The crops are grown in the winter season, that is from October to March are called rabi crops.

Seeds: A plant’s fertilized ovules, from which a new plant may grow, are called seeds.

Silo: Harvested grains are usually dried before being stored because moisture encourages the growth of microorganism. They are then stored in metal or earthen container, gunny bags. Such stores are also called silo.

Sowing: It is a process to put seeds in the soil.

Storage: It is to keep crop grains safe from moisture, insects and rats for a long time.

Threshing: The process of separation of grains from the chaff in the harvested plant is called threshing.

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Answer 3

NCERT Class 8 Science Notes Chapter 1 Crop Production and Management.

We already know that:

• All living organisms require food.
• The energy from food is utilized by an organism for carrying out its various life processes such as digestion, respiration and excretion.
• Plants can make their food themselves but animals including humans cannot.
• We get our food from plants or animals, or both.

In our country three categories of crops are grown:

• Kharif Crops: The crops which are grown in the rainy season (i.e., from June to September) are called Kharif crops. Paddy, maize, soybean, groundnut, and cotton are Kharif crops.
• Rabi Crops: The crops are grown in the winter season (i.e., from October to March) are called rabi crops. Examples of rabi crops are wheat, gram, pea, mustard, and linseed.
• Zaid Crops (or Summer Crops): The crops grown in the summer season are ( called zaid crops). Moong, muskmelon, watermelon, cucumber, gourd and bitter gourd are examples of zaid crops.

Cultivation of crops involves the following activities:

• Soil Preparation: It involves loosening and tilling of the soil (i.e., ploughing and watering).
• Sowing: Sowing is the process of putting seeds in the soil.
• Adding Manure and Fertilizers: The substances, which are added to the soil in the form of nutrients to improve the production of the crops and fertility of the soil are called manure and fertilizers.
• Irrigation: Supply of water to crops at appropriate intervals is called irrigation.
• Protection from Weeds: Weeds are the unwanted plants that grow along with the crops. Its removal is a must for the better growth of the crops. These can be controlled by spraying certain chemicals, called weedicides, like 2, 4-D.
• Harvesting: The cutting of the crop after it is mature is called harvesting.
• Storage: If the crop grains are to be kept for a longer time, they should be safe from moisture, insects and rats.

Humus: Humus is the top layer of the soil formed by decaying or decomposition of organic matters like animal remains, shed leaves, the dung of cattle.

Pests: Pests are the insects or rodents that destroy much of our crop yield. Thus, it is necessary to save crops from pests.

Important agricultural tools:

• Plough: This is used for tilling the soil, adding fertilizers to the crop, removing the weeds, scraping of soil, etc. This implement is made of wood and drawn by a pair of bulls.
• Hoe: It is used for removing weeds and for loosening the soil.
• Cultivator: Used for ploughing. It is driven by a tractor. Use of cultivator saves labour and time.
• Traditional Tool: The tool used traditionally for sowing seeds is shaped like a funnel.
• Seed Drill: Used for sowing with the help of tractors. This tool shows the seeds uniformly at a proper distance and depth.
• Sickle: Used for manual harvesting.

Food from Animals: Like plants, the animals also provide us with different kinds of food like fish, meat and eggs.

Fumigation: Fumigation is the most effective method for checking the growth of insects by providing smoke or chemicals in the gaseous state without affecting the grain.

Agricultural practices: There are various activities that have to be performed, before sowing and up to harvesting. These are called agricultural practices.

Animal husbandry: Animals reared at home or on a farm, have to be provided with proper food, shelter and care, when this is done on a large scale it is called animal husbandry.

Crop: When plants of the same kind are grown at a place in a regular manner on a large scale, it is called a crop.

Fertilizer: Fertilizers are chemicals which are rich in a particular nutrient like nitrogen, phosphorus and potassium.

Granaries: The harvested grains, usually are stored in huge stores, after they are’ properly dried in sunlight. Such stores are called granaries.

Harvesting: The cutting of the crop after it is mature is called harvesting.

Irrigation: Supply of water to crops at appropriate intervals is called irrigation.

Kharif Crops: The crops which are grown in the rainy season, that is from June to September are called kharif crops.

Manure: Manures are decomposed organic matter obtained from plant or animal waste.

Plough: The device used for tilling or ploughing is called plough.

Rabi Crops: The crops are grown in the winter season, that is from October to March are called rabi crops.

Seeds: A plant’s fertilized ovules, from which a new plant may grow, are called seeds.

Silo: Harvested grains are usually dried before being stored because moisture encourages the growth of microorganism. They are then stored in metal or earthen container, gunny bags. Such stores are also called silo.

Sowing: It is a process to put seeds in the soil.

Storage: It is to keep crop grains safe from moisture, insects and rats for a long time.

Threshing: The process of separation of grains from the chaff in the harvested plant is called threshing.

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