NCERT solutions for Class 8 Science Chapter-1 “Crop Production And Management”
Q.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 in large scale at a place is called ______.
(b) The first step before growing crop is _____ of the soil.
(c) Damaged seeds would ______ on top of water.
(d) For growing a crop, sufficient sunlight and ______ and ______ from the soil are essential.
Ans- (a) crop. (b) preparation. (c) float (d) water, nutrients
Q.2- Match items in column ‘A’ with those in column ‘B’.
Q.3- Give two examples of each :
(a) Kharif crop
(b) Rabi crop
Ans- (a) Kharif crop : Maize, paddy.
(b) Rabi crop : Wheat, gram.
Q.4- Write a paragraph in your own words on each of the following:
(a) Preparation of soil. (b) Sowing
(c) Weeding. (d) Threshing
Ans- (a) Preparation of soil- Before growing a crop, it is necessary to make the soil fit for agricultural use. It is done by loosening and turning the soil. The loose soil allows the roots to penetrate deep into the soil and breathe easily. It also helps in the growth of earthworms and other microbes, which add humus and other essential nutrients to the soil.
(b) Sowing- The process of putting seeds into the soil is called sowing. Sowing can be done with hands by broadcasting, by seed drills or by transplantation method.
(c) Weeding- The removal of unwanted plants (weeds) is called weeding. It is necessary because weeds compete with crop for water, nutrients, space and sunlight. Thus they affect the growth of a crop. It is done by uprooting the weeds with hands, seed drills and by using weedicides like 2,4-D.
(d) Threshing- The process of separating foodgrains from chaff is called threshing. Threshing is carried out with the help of machines like thresher and combine. Combine is a harvester as well as thresher.
Q.5- Explain how fertilizers are different from manure?
Q.6- What is irrigation? Describe two methods of irrigation which conserve water.
Ans- The supply of water to crops at regular intervals is called irrigation.
The methods of irrigation which conserve water are-
(a) Sprinkler System- This system is most useful on the uneven lands where sufficient water is not available. The rotating nozzles are fitted to the ends of the pipes, from where the water sprinkles on the crop as if it is raining.
(b) Drip System- In this system, the water falls drop by drop near the plant roots. It is the best technique for watering the fruit plants, gardens and trees. Water is not wasted at all. It is the boon in regions where the water is scarce.
Q.7- If wheat is sown in the kharif season, what would happen?
Ans- Wheat is a rabi crop. It is grown in winter and requires less water. If wheat is sown in kharif season, its production will be affected due to excess of rainy water.
Q.8- Explain how soil gets affected by the continuous plantation of crops in a field?
Ans- The crops grown in the fields take nutrients from the soil. If crops are grown continuously in s field, the soil becomes deficient in nutrients, means the soil becomes infertile.
Q.9- What are weeds? How can we control them?
Ans- The unwanted plants grown with crops are called weeds. They compete with crops for water, nutrients, space and sunlight, thus affect the growth of a crop.
Methods to control the weeds are-
(a) Mechanical Method- This method includes uprooting the weeds with the help of khurpi, hand hoeing, tilling and ploughing.
(b) By Weedicides- Some weeds can only be destroyed by spraying weedicides. They kill weeds without damaging the crop.
(c) Biological Method- Some weeds can be destroyed by some specific organisms. For example, Opuntia (weed) is controlled by cochineal insect.
Q.10- Arrange the following boxes in proper order to make a flowchart of sugarcane crop production.
Ans- The correct order is :
1) Preparation of soil.
2) Ploughing the field.
7) Sending crop to sugar factory.
Q.11- Complete the following word puzzle with the help of clues given below :
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.
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 the chaff.