NCERT Class 8 Science Chapter 1 - Crop Production and Management

Chapter 1 - Crop Production and Management

Question and Answers
Question 1: Define
a) Crop - When plants of same kind are grown and cultivated at one place on a large scale, it is called crop.

b) Ploughing - The process of loosening and turning of the soil is called ploughing.

c) Crumbs - Crumbs are nothing but big pieces of soil. These crumbs are broken down into smaller pieces with the help of plank.

Question 2: Give 2 examples of
a) Kharif crop
b) Rabi crop
Answer:
a) Kharif crop - Soyabean, Groundnut
b) Rabi crop - Mustard, Linseeds

Question 3: If wheat is sown in the kharif crop, what would happen? Discuss.
Answer: Kharif crops are the crops that are sown in rainy season. If we sow wheat in rainy season, then the wheat crop would be destroyed due to excessive increase in water level, moisture etc. Therefore, it is not wise to sow wheat in kharif season.

Question 4: Define
a) Sowing - The process of scattering or putting seeds into the ground is called sowing.

Question 5: 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: Preparation of soil is the first step in cultivating a crop for food production. It requires 3 steps - ploughing, levelling, manuring.

b) Sowing: The process of scattering or putting seeds into the ground is called sowing. Before sowing good quality seeds are selected. Good quality seeds are clean and healthy, free disease and infection. There are two methods of sowing seeds - Sowing by hand and Sowing with a seed drill. Sowing with a seed drill saves time and labour.

c) Weeding: The unwanted plants which grow along with a cultivated crop are called weeds. The process of removing weeds from a crop field is called weeding. The best time for the removal of weeds is before they produce flowers and seeds. The various methods of weeding are - Removal of weeds by pulling them out with hand, Removal of weeds by using a trowel, Destroying the weeds by spraying special chemicals called weedicides.

d) Threshing - Process of separating the chaff from the crop is known as threshing. Threshing is done by a machine called ‘combine’ which is a harvester as well as a thresher. Threshing is also done by winnowing where wind is used to separate the chaff from crops.

Question 6: Define
a) Irrigation - The process of supplying water to the crop plants in the field is called irrigation.

Question 7: Explain how fertilizers are different from manure.
Answer: Fertilizers are chemical substance which are rich in particular nutrient. They are produced in factories. They don't provide any humus to the soil. They help in getting a better yield.
On the other hand, manure is a natural substance that is very rich in humus. It can be prepared in fields by decomposition of cow dung, human waste etc. The use of manure improve soil texture as well as its water retaining capacity.

Question 8: What is irrigation? Describe two methods of irrigation which conserve water.
Answer: All crops in plant need water for their growth. Therefore, it is necessary to water plants periodically. The process of supplying water to the crop plants in the field is called irrigation.
Modern methods of irrigation helps us to use water economically. These methods include
• Sprinkler System: This system is more useful on the uneven land where sufficient water is not available. The perpendicular pipes, having rotating nozzles on top are joined to the main pipeline at regular intervals. When water is allowed to flow through the main pipe under pressure with the help of a pump, it escapes from the rotating nozzles. It gets sprinkled on the crop as if it is raining. Sprinkler is very useful for sandy soil.
• Drip system: In this system, the water falls drop by drop just at the position of the roots. So it is called drip system. It is the best technique for watering fruit plants, gardens and trees. The system provides water to plants drop by drop. Water is not wasted at all. It is a boon in regions where availability of water is poor.

Question 9: Define:
a) Weeds - The unwanted plants which grow along with a cultivated crop are called weeds.

b) Weeding - The process of removing weeds from a crop field is called weeding.

c) Weedicides - Destroying the weeds by spraying special chemicals called weedicides.

Question 10: What are the weeds? How can we control them?
Answer: The unwanted plants which grow along with a cultivated crop are called weeds. We can remove weeds by a process called weeding. The best time for the removal of weeds is before they produce flowers and seeds. The various methods of weeding are:
→ Removal of weeds by pulling them out with hand.
→ Removal of weeds by using a trowel.
→ Destroying the weeds by spraying special chemicals called weedicides.

Question 11: Define

a) Animal Husbandry - It refers to the care of the livestock animals. Livestock animals include horse, cow, chicken or any other animal that is raised for meat, wool or other functional use. 

b) Crop rotation - Crop rotation is the process of growing different types of crops in the same area in the growing seasons.

Question 12: Define
a) Agriculture - The science and art of cultivation on the soil, raising crops and rearing livestock. It is also called farming.

Question 13: Write the advantages of manure.
Answer: The organic manure is considered better than fertilisers because
• It enhances the water holding capacity of the soil.
• It makes the soil porous due to which exchange of gases becomes easy.
• It increases the number of friendly microbes.
• It improves the texture of the soil.

Question 14: Why should be weeds removed in a crop field?
Answer: Weeding is necessary since weeds compete with the crop plants for water, nutrients, space and light. Thus, they affect the growth of the crop. Some weeds interfere even in harvesting and may be poisonous for animals and human beings.