NCERT Solutions for Class 8 Science Chapter 1 Crop Production and Management

1. 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 _____________.

Answer: crop

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

Answer: preparation

(c) Damaged seeds would _____________ on top of water.

Answer: float

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

Answer: water, nutrients

2. Match items in column A with those in column B.

Column A	Column 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:

Column A	Column B
(i) Kharif crops	(e) Paddy and maize
(ii) Rabi crops	(d) Wheat, gram, pea
(iii) Chemical fertilisers	(b) Urea and superphosphate
(iv) Organic manure	(c) Animal excreta, cow dung urine and plant waste

3. Give two examples of each – (a) Kharif crop (b) Rabi crop

Answer: a) Kharif Crop: Paddy, maize b) Rabi Crop: Wheat, gram, pea

4. Write a paragraph in your own words on each of the following.(a) Preparation of soil (b) Sowing (c) Weeding (d) Threshing

Answer:

1. Preparation of soil: For growing a crop first step is preparation of soil. Preparation of soil involves loosening of soil.this method is called ploughing or tilling. This is done so that, roots of the crop should penetrate deep into the soil, to extracts water and essential nutrients. Benefit of loosening of soil it that, it promote the growth of microbes and earthworms into the soil, which helps in formation of humus and other nutrients. Ploughing brings nutrient rich layer of soil on the top. Thus, these nutrient is absorbed by the plants for their growth
2. Sowing: Sowing is the process of adding seed into the soil for their germination and further growth of plants. Good quality seeds should be selected for sowing, this will help to increase yield of crop. Sowing is now days done using seed drills. With the help of seed drill, seeds are spread equally in the soil at appropriate depth.
3. Weeding: Unwanted plants in crop field is called weeds. Weeds extract nutrient from the soil for their growth, thereby reducing nutrients for the crops. This affects the productivity and quality of crops. Removal of weeds from the fields is called weeding. Various weeding methods are used to prevent growth of weeds and remove weeds. Some of them are use of weedicides, tilling of soil, manual cutting weeds.
4. Threshing: Separation of seeds and grains from the chaff is known as threshing. It carried out after harvesting the crops. Machine combine is used for harvesting and threshing .

5. Explain how fertilisers are different from manure.

Answer:

Fertilisers	Manure
These are commercially available plant nutrients	These are prepared by decomposition of plants and animal waste
Fertilisers can be organic or inorganic	Manure is organic nature
Provides nutrients like potassium, nitrogen, etc for growth and development of plants.	Enriches soil quality with organic matter and nutrients
Do not provide humus to soil	Provides humus to soil
If used in excess causes soil pollution and cannot replenish organic matter in soil	No pollution is caused and helps in recycling of organic wastes

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

Answer: Process in which water is supplied to crops at different time intervals is called irrigation. Two methods used for irrigation which conserve water are sprinkler irrigation system and drip irrigation system.

• Sprinkler irrigation system – Generally sprinkler irrigation system is used on uneven lands. In this system, water is supplied to central locations in the field. With the help of pump, water is allowed to flow under high pressure, due to which, water gets sprinkled on crops.
• Drip irrigation system – In drip irrigation system, water is supplied to the base of the plants or crops near roots, drop by drop with the help of thin tube. It prevents wastage of water. This method is most suitable where availability of water is low.

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

Answer: Kharif season mainly includes rainy season which is unfavourable for growth of wheat. If wheat is sown in kharif season whole crop may get destroyed due to lack of optimum temperature, adaptation and pests. Thus, one must not sow wheat in kharif season.

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

Answer: For proper growth, plants require nutrients from soil. If there is continuous plantation of crops in a field, then plant will continuously absorbs essential nutrients like potassium, nitrogen, etc from the soil. Thus, there will be decrease in soil nutrients and ultimately this will affect productivity of crops.

9. What are weeds? How can we control them?

Answer: Unwanted plants in crop field are called weeds. Weeds extract nutrient from the soil for their growth, thereby reducing nutrients for the crops. This affects the productivity and quality of crops. Removal of weeds from the fields is called weeding. Various weeding methods are used to prevent growth of weeds and remove weeds. Some of them are – use of weedicides, tilling of soil, manual cutting weeds.

10. Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.

Answer: 1) Preparation of soil 2) Ploughing the field 3) Sowing 4) Manuring 5) Irrigation 6) Harvesting 7) Sending crop to sugar factory

11. Complete the following word puzzle with the help of clues given below – Down 1. Providing water to the crops. 2. Keeping crop grains for a long time under proper conditions. 5. Certain plants of the same kind grown on a large scale. Across 3. A machine used for cutting the matured crop. 4. A rabi crop that is also one of the pulses. 6. A process of separating the grain from chaff.

Answer:

• Down 1. Irrigation 2. Storage 5. Crop
• Across 3. Harvestor 4. Gram 6.Winnowing

Check other lessons NCERT Solutions for Class 8

Download free NCERT textbook class 8 Science – Chapter 1 Crop Production and Management