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CBSE Sample Paper Class 8 Science Crop Production and Management
Crop Production and Management
1.) Short Questions (1 marks each – 12 marks)
a.) How green plants synthesize their own food?
b.) What is crop?
c.) Which type of crops are grown in India?
d.) What is ploughing?
e.) What is crop rotation?
f.) Which bacteria helps us to fix atmospheric nitrogen?
g.) What is irrigation?
h.) Write the sources of irrigation?
i.) What are weeds?
j.) What is harvesting?
k.) What is threshing?
l.) What is animal husbandry?
2.) Answer these questions briefly (3 marks each – 30 marks)
a.) How agriculture was born?
b.) How the preparation of soil is done?
c.) Describe Kharif crop and Rabi crop with examples?
d.) Why manures are important for growing crops?
e.) Write the differences between manure and fertilizers.
f.) Write the importance of water in growing crops.
g.) What is sprinkler system? In which condition it is used?
h.) What is drip system of irrigation? Write about the conditions in which it is used.
i.) Why weeding is a necessary process for the growth of crops? Write the methods of weed removal.
j.) How food is stored after harvesting?
3.) Fill in the blanks (1 marks each – 4 marks)
a.) ________ seeds float in the water.
b.) Chemicals which controls weeds are called _________ .
c.) Dried ______ leaves are used to store grains at home.
d.) Organic substance which obtained from the decomposed plant or animal is called ________ .
4.) Mention the uses of the following (1 marks each – 4 marks)
a.) Plough –
b.) Hoe –
c.) Seed drill –
d.) Combine –
Answer
(1) Short questions (1 marks each – 12 marks)
(a) How green plants synthesize their own food?
Answer – Green plants synthesize their own food by using water from the soil and carbon dioxide from the air in the presence of sunlight, this process is called photosynthesis.
(b) What is crop?
Answer – When on a large scale plants of same kind are cultivated it is called crop.
(c) Which type of crops are grown in India?
Answer – In India Kharif crop and Rabi crop are grown.
(d) What is ploughing?
Answer – Ploughing is a process of preparation of soil for cultivation of crop, this process helps in loosening and turning of the soil.
(e) What is crop rotation?
Answer – Crop rotation is used by farmers to replenish the soil with nutrients. In this process different crops are grown alternatively.
(f) Which bacteria helps us to fix atmospheric nitrogen?
Answer – Rhizobium bacteria present in the nodules of roots of leguminous plants helps us to fix atmospheric nitrogen.
(g) What is irrigation?
Answer – Irrigation is a important process in crop cultivation. In this process water is supplied to crops on a regular interval.
(h) Write the sources of irrigation?
Answer – The sources of irrigation are wells, tubewells, ponds, lakes, canals and dams.
(i) What are weeds?
Answer – In the field of cultivation there is other undesirable plants that grow and takes away the nutrients of the soil which harm the crop’s growth, these undesired plants are called weeds.
(j) What is harvesting?
Answer – After the crop matures cutting or pulling it out from the soil is known as harvesting.
(k) What is threshing?
Answer – Threshing is a method used after harvesting of crops. This method is used to separate grains from the chaff.
(l) What is animal husbandry?
Answer – Animal husbandry is a process in which animals are reared at home or in farms and they have to be provided with food, shelter, water and care in a large scale.
(2) Answer these questions briefly (3 marks each – 30 marks)
(a) How agriculture was born?
Answer – In ancient time people were nomadic in nature. They used to wander from place to place in search of food and shelter. At first they used to eat raw fruits and vegetables. Then they started to hunt animals for food. Later they started cultivating land to grow crops. That’s how agriculture was born.
(b) How the preparation of soil is done?
Answer – Preparation of soil is first step of cultivation of crop. In this process soil is turned and loosen. It is one the most important step for cultivation of crop. This process helps plant’s root to penetrate deep into the soil and allows the roots to breath easily. Plants can absorb water, nutrients and minerals.
Plough, hoe and cultivators are used prepare the soil.
(d) Describe Kharif crop and Rabi crop with examples?
Answer –
Kharif crops are the crop which are sown in the rainy season in India. This crops are sown from June to September month. Examples of kharif crops include paddy, maize, soyabean etc. Rabi crops are the crop which are sown in the winter season in India. This crops are sown from October to March. Examples of Rabi crops include wheat, gram, pea, mustard etc.
(d) Why manures are important for growing crops?
Answer – When crops are cultivated in a field for a long time, the soil of the field becomes poor in nutrients. To replenish the soil with nutrients farmers add manure to the fields. Manure is an organic substance which is obtained from decomposed plant and animals. Improper or insufficient manuring can result in weak plants.
(e) Write the differences between manure and fertilizers.
Answer –
Manure |
Fertiliser |
(1) Manure is an organic substance which is obtained from decomposed plant and animals. |
(1) Fertiliser is an inorganic salt made by humans. |
(2) Manure can be easily prepared in home. |
(2) Fertiliser can’t be prepared in home. |
(3) Manure is prepared in fields. |
(3) Fertiliser is prepared in factories. |
(4) Manure provide humus to the soil. |
(4) Fertiliser doesn’t provide humus to the soil. |
(5) Manure is not so rich in nutrients as fertilisers. |
(5) Fertilisers are very rich in nutrients. |
(f) Write the importance of water in growing crops.
Answer – As all living beings crops also need water to live. Water is essential for the growth and development of the plants. Water is absorbed by the roots of the plants. When planes absorb water with the roots the nutrients and minerals are also get absorbed along with water. Water is also very important for the germination of seeds as germination process doesn’t take place under dry conditions. Water also protects plants from hot air and frost. So for healthy crops field has to be watered regularly.
(g) What is sprinkler system? In which condition it is used?
Answer – In sprinkler system perpendicular pipes are used. They have rotating nozzles on the top which are joined to the main pipeline. The nozzles are situated at regular intervals. When water flows through the pipeline. With the help of the pump water escapes through the nozzle. The water sprinkles over the crops as raining.
Sprinkler system of irrigation is used in the uneven places where sufficient water is not available.
(h) What is drip system of irrigation? Write about the conditions in which it is used.
Answer – In drip system of irrigation water falls drop by drop directly near the roots of the plants. This is the best technique where water isn’t wasted at all.
Drip system of irrigation is used in the places where water availability is very less.
(i) Why weeding is a necessary process for the growth of crops? Write the methods of weed removal.
Answer – Weeding is a necessary process because weeds compete with cultivating cropsfor water, nutrients, space and light. Which effects the growth of the crop significantly. Sometimes weeds even interfere in harvesting and sometimes weeds can be poisonous for animals and human beings. So weeding is necessary for growth of crop.
Some methods of weeding includes manual removal using khurpi and seed drill, and weeds are also controlled by using chemicals called weedicides.
(j) How food is stored after harvesting?
Answer – After harvesting the crops, grains are stored. Harvested grains are stored from away from the moisture. It should be kept safe from rats, insects and microorganisms. Freshly harvested grains contain moisture in them so if they aren’t stored without drying they may get spoilt or attacked by different organisms and making them unfit for use. So grains should be dried properly before storage. Farmers usually store grains in jute bags and for large scale storage silos and granaries are used. In home dried neem leaves are also used for storage of grains.
(3) Fill in the blanks (1 marks each – 4 marks)
(a) Damaged seeds float in the water.
(b) Chemicals which controls weeds are called weedicides.
(c) Dried neem leaves are used to store grains at home.
(d) Organic substance which obtained from the decomposed plant or animal is called manure.
(4) Mention the uses of the following (1 marks each – 4 marks)
(a) Plough – Plough is used for the tiling of the soil.
(b) Hoe – Hoe is a tool used for removal of weed and loosening soil.
(c) Seed drill – Seed drill is used for sowing seed with the help of a tractor.
(d) Combine – Combine is a machine used for threshing and harvesting.