NCERT Class 8 Science Chapter 1 Solution
Brief Information: This post contains the solution for Chapter 1 Crop Production and Management of Class 8 of the CBSE and also Gujarat Board (GSEB) books by GCERT (based on new NCERT).
Q1. Select the correct word from the following list and fill in the blanks.
(a) The same kind of plants grown and cultivated on a large scale at a place is called crop.
(b) The first step before growing crops is preparation of the soil.
(c) Damaged seeds would float on top of the water.
(d) For growing a crop, sufficient sunlight and water and nutrients from the soil are essential.
Q.2 Match items in column A with those in column B.
- (i) Kharif crops – (e) Paddy and maize
- (ii) Rabi crops – (d) Wheat, gram, pea
- (iii) Chemical fertilisers – (b) Urea and super phosphate
- (iv) Organic manure – (c) Animal excreta, cow dung, urine and plant waste
Q.3. Give two examples of each.
(a) Kharif crop – Paddy, Sugarcane, Cotton, Soyabean, Groundnut
(b) Rabi crop – Wheat, Mustard, Gram, Pea
Q.4. Write a paragraph in your own words on each of the following
(a) Preparation of soil
Ans. Soil is the most vital part for agriculture. Preparing soil is the first step for agriculture. Preparation of soil include steps like loosening and turning soil, leveling soil and adding of nutrients in form of manure. Loose and turned soil allows the penetration of roots deep into the soil. The loose soil allows the roots to breathe easily even when they go deep into the soil. It brings the nutrition rich soil to the top so that plants can use these nutrients. The loosened soil helps in the growth of earthworms and microbes present in the soil. These organisms are friends of the farmer since they further turn and loosen the soil and add humus to it by decomposing dead plants and animals. The process of loosening and turning of the soil is called tilling or ploughing. This is done by using a plough. Ploughs are made of wood or iron. If the soil is very dry, it may need watering before ploughing. The ploughed field may have big clumps of soil called crumbs. It is necessary to break these crumbs. Leveling the field is beneficial for sowing as well as for irrigation. Leveling of soil is done with the help of a leveller. Sometimes, manure is added to the soil before tilling. This helps in proper mixing of manure with soil. The soil is moistened before sowing.
Ans. The process of planting the seeds into the soil id called sowing. Before sowing the selection of seeds is done. The damaged seeds are separated from the healthy seeds. The healthy seeds can be separated from the damaged ones by putting seeds into water. The healthy seed sinks while the damages seed floats. Traditionally, a funnel shaped tool was used for sowing. The seeds are filled into the funnel, passed down through two or three pipes having sharp ends. These ends pierce into the soil and place seeds there. Nowadays the seed drill is used for sowing with the help of tractors. This sows the seeds uniformly at equal distance and depth. It ensures that seeds get covered by the soil after sowing. This protects seeds from being eaten by birds. Sowing by using a seed drill saves time and labour.
Ans. The undesirable plants growing with the crops are called weed. The process of removal of these weeds is called weeding. The weeding is necessary as weeds compete with the crops for water, nutrients, space and light. Thus, they affect the growth of crop. Some weeds are also poisonous for animals and human beings and interfere in harvesting. Farmers adopt many ways to remove weeds and control their growth. Tilling before sowing of crops helps in uprooting and killing of weeds, which may then dry up and get mixed with the soil. The best time for the removal of weeds is before they produce flowers and seeds. The manual removal includes physical removal of weeds by uprooting or cutting them close to the ground, from time to time. This is done with the help of a khurpi. A seed drill is also used to uproot weeds. Weeds are also controlled by using certain chemicals, called weedicides like 2,4-D. These are sprayed in the fields to kill the weeds.
Ans. After harvesting, the grain needs to be separated from the chaff. This process is called threshing. This is carried out with the help of a machine called ‘combine’ which is in fact a harvester as well as a thresher.
Q.5. Explain how fertilisers are different from manure.
Fertiliser is a man-made inorganic salt.
Manure is a natural substance obtained by the decomposition of cattle dung and plant residues.
Fertiliser is prepared in factories.
Manure can be prepared in the fields.
Fertiliser does not provide any humus to the soil.
Manure provides a lot of humus to the soil.
Fertilisers are very rich in plant nutrients like nitrogen, phosphorus and potassium.
Manure is relatively less rich in plant nutrients.
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 time and frequency of irrigation varies from crop to crop, soil to soil and season to season. The water can be conserved by adopting following method of irrigation:
1. Sprinklers System – In this System a 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.
2. Drip System – In this system, the water falls drop by drop directly near the roots. So it is called drip system. It is the best technique for watering fruit plants, gardens and trees.
Q.7. If wheat is sown in the kharif season, what would happen? Discuss.
Ans. Wheat is a Rabi crop. It is grown in winter season in the months from October to March. Wheat require cold and dry weather. If wheat seeds are sown in the kharif season than the seed will not sprout due to unfavourable climatic condition.
Q.8. Explain how soil gets affected by the continuous plantation of crops in a field.
Ans. Crop plants require nutrition for the growth. Plants get the nutrition from the soil. If crops are planted continuously in the field, the nutrition in the soil gets exhausted and the fertility of the soil decrease. Therefore to maintain the nutrition level in the soil, manuring is done by the farmer. The field can also be left fallow for few years for recovering the fertility (nutrition level) of the soil.
Q.9. What are weeds? How can we control them?
Ans. The undesirable plants which grows with the crops are called weed. The compete with crops for nutrition, water, space and light. Thus, affect the growth of crops. The process of removal of weeds to control their growth is called weeding. Weeding cane be done by following methods:
1. Manually – The farmer removes the weed by their hands.
2. Seed Drill – Seed drill is dragged by tractor on field to remove the weeds during tilling process
3. Weedicides – The chemicals that kills the weeds without affecting the growth of crops are called weedicides e. 2,3-D. They are sprayed over the field to kill the weeds.
Q.10. Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.
Ans. Proper flow of sugarcane production is given below
5. Preparation of soil
6.Ploughing the field
1. 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 chaff.