Case Study Questions Class 8 Science Chapter 1 Crop Production and Management
CBSE Class 8 Case Study Questions Science Crop Production and Management. Important Case Study Questions for Class 8 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Crop Production and Management.
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CBSE Case Study Questions Class 8 Science Crop Production and Management
Case study 1
When plants of the same kind arecultivated at one place on a large scale,it is called a crop. For example, crop ofwheat means that all the plants grownin a field are that of wheat.You already know that crops are ofdifferent types like cereals, vegetablesand fruits. These can be classified on thebasis of the season in which they grow.India is a vast country. The climaticconditions like temperature, humidityand rainfall vary from one region toanother. Accordingly, there is a richvariety of crops grown in different partsof the country. Despite this diversity,two broad cropping patterns can beidentified. These are:(i) Kharif Crops: The crops which aresown in the rainy season are calledkharif crops. The rainy season in Indiais generally from June to September.Paddy, maize, soyabean, groundnut andcotton are kharif crops.(ii) Rabi Crops: The crops grown in thewinter season (October to March) arecalled rabi crops. Examples of rabicrops are wheat, gram, pea, mustardand linseed.Besides these, pulses and vegetables are grown during summer at manyplaces.
Que. 1) Soyabean which is generally sown from June to September isan example of …………………………………………………………………………………….. crops.
(a) Kharif
(b) Zaid
(c) Rabi
(d) Fiber
Que. 2) Which of the following mentioned crop is included in the category of Rabi Crop?
(a) Paddy
(b) Cotton
(c) Groundnut
(d) Mustard
Que. 3) Which among the following factors or conditions does NOT affect the crop production?
(a) Temperature
(b) Humidity
(c) Literacy
(d) Rainfall
Que. 4) What do you understand by the term “Crop”?
Que. 5) What are Rabi Crops? Enlist some of the examples of Rabi Crops.
Answer Key
Que. 1) (a) Kharif
Que. 2) (d) Mustard
Que. 3) (c) Literacy
Que. 4) Answer: When plants of same kind are cultivated at one place on a large scale in order to provide food for a large population, it is called a crop.
Que. 5) Answer: Rabi crops are grown in winter season mainly from October to March. Examples of Rabi crop include wheat, gram, pea, linseed and mustard.
Case study 2
The preparation of soil is the first step before growing a crop. One of the mostimportant tasks in agriculture is to turn the soil and loosen it. This allows theroots to penetrate deep into the soil. The loose soil allows the roots to breatheeasily even when they go deep into the soil. Why does the loosening of soil allowthe roots to breathe easily? The loosened soil helps in the growthof earthworms and microbes present in the soil. These organisms are friends ofthe farmer since they further turn and loosen the soil and add humus to it.But why the soil needs to be turned and loosened? You have learnt in the previousclasses that soil contains minerals, water, air and some living organisms.In addition, dead plants and animals get decomposed by soil organisms. Inthis way, various nutrients in the dead organisms are released back into thesoil. These nutrients are again absorbed by plants. Since only a few centimetres of thetop layer of soil supports plant growth, turning and loosening of soil brings thenutrient-rich soil to the top so that plants can use these nutrients. Thus, turning and loosening of soil is very important for cultivation of crops. The process of loosening and turning of the soil is called tilling or ploughing. This is done by using a plough. Ploughsare made of wood or iron. If the soil is very dry, it may need watering beforeploughing. The ploughed field may have big clumps of soil called crumbs. It isnecessary to break these crumbs. Levelling the field is beneficial for sowing as well as for irrigation. Levelling of soil is done with the help of a leveller.Sometimes, manure is added to the soil before tilling. This helps in propermixing of manure with soil. The soil is moistened before sowing.
Que. 1) Which of the following organism is widely known as the friends of farmers?
(a) Cow
(b) Earthworm
(c) Dog
(d) Cockroach
Que. 2) The process of loosening and turning of soil is commonly termed as …………………………………………………………………………………………...
(a) Watering
(b) winnowing
(c) Ploughing
(d) Harvesting
Que. 3) Why is manure sometimes added to the soil before the process of tilling?
(a) For proper mixing of manure in soil
(b) To reduce the workload
(c) To disinfect soil
(d) For levelling properly
Que. 4) Explain in detail the importance of turning the soil and loosening it.
Que. 5) How is levelling of the soil done? What is the benefit of levelling?
Answer Key
Que. 1) (b) Earthworm
Que. 2) (c) Ploughing
Que. 3) (a) For proper mixing of manure in soil
Que. 4) Answer: Turning of soil allows roots to penetrate deep into the soil. This loosening allows roots to breathe easily. Turning and loosening also helps in the growth of earthworms and microbes present in soil.
Que. 5) Answer: Levelling of soil is done with the help of a leveller. Levelling in the field is beneficial for sowing as well as for irrigation.
Case study 3
Before sowing the seeds, it is necessary tobreak soil clumps to get better yield. Thisis done with the help of various tools.The main tools used for this purpose arethe plough, hoe and cultivator.Plough: This is being used sinceancient times for tilling the soil, addingfertilisers to the crop, removing the weedsand turning the soil. This is made ofwood and is drawn by a pair of bulls orother animals (horses and camels). Itcontains a strong triangular iron stripcalled ploughshare. The main part of theplough is a long log of wood which iscalled a plough shaft. There is a handleat one end of the shaft. The other end isattached to a beam which is placed onthe bulls’ necks. One pair of bulls and aman can easily operate the plough.The indigenous wooden plough isincreasingly being replaced by ironploughs nowadays.Hoe: It is a simple tool which is usedfor removing weeds and for looseningthe soil. It has a long rod of wood oriron. A strong, broad and bent plate ofiron is fixed to one of its ends and works like a blade. It is pulled byanimals Cultivator: Nowadays ploughing isdone by tractor-driven cultivator. Theuse of cultivator saves labour and time.
Sowing is an important part of cropproduction. Before sowing, good quality,clean and healthy seeds of a goodvariety—are selected. Farmers prefer touse seeds which give high yield.
Are there seeds which float onwater? Would those be lighter orheavier than those which sink? Whywould they be lighter? Damaged seedsbecome hollow and are thus lighter.Therefore, they float on water.This is a good method forseparating good, healthy seeds fromthe damaged ones.Before sowing, one of the importanttasks is to know about the tools usedfor sowing seeds. Traditional tool: The tool usedtraditionally for sowing seeds isshaped like a funnel. Theseeds are filled into the funnel,passed down through two or threepipes having sharp ends. Theseends pierce into the soil and placeseeds there.Seed drill: Nowadays the seed drillis used for sowing with the helpof tractors. This sows the seedsuniformly at equal distance and depth.It ensures that seeds get covered by thesoil after sowing. This protects seedsfrom being eaten by birds. Sowing byusing a seed drill saves time and labour.Appropriate distance between theseeds is necessary to avoid overcrowdingof plants. This allows plants to getsufficient sunlight, nutrients and waterfrom the soil. At times a few plantsmay have to be removed to preventovercrowding.
Que. 1) Which one of the following equipment is NOT used for the purpose of tilling of soil?
(a) Plough
(b) Hoe
(c) Cultivator
(d) Hammer
Que. 2)………………………………………………………………………………… is used to sow seeds uniformly at equal distance and depth?
(a) Sickle
(b) Spade fork
(c) Seed drill
(d) Rake
Que. 3) What is the most important thing to be done before sowing of the seeds?
(a) Tilling
(b) seeding
(c) Harvesting
(d) Threshing
Que. 4) What needs to be taken care of before the process of sowing?
Que. 5) Explain a method to determine the damaged seeds before sowing.
Answer Key
Que. 1) (d) Hammer
Que. 2) (c) Seed drill
Que. 3) (a) Tilling
Que. 4) Answer: Thing to be taken care of before sowing are to select good quality, clean and healthy seeds of good variety. It is also important to select the seeds which give high yield.
Que. 5) Answer: To determine damaged seeds, they are put in a vessel containing water. Some seeds will float and some seeds will sink. The seeds floating are lighter because they are hallow from inside. Thus, damaged seeds can be separated from good quality seeds.
Case study 4
The substances which are added to thesoil in the form of nutrients for thehealthy growth of plants are calledmanure and fertilisers.Soil supplies mineral nutrients to thecrop plants. These nutrients areessential for the growth of plants. Incertain areas, farmers grow crop aftercrop in the same field. The field is neverleft uncultivated or fallow. Imagine whathappens to the nutrients?Continuous cultivation of cropsmakes the soil poor in nutrients.Therefore, farmers have to add manureto the fields to replenish the soil withnutrients. This process is calledmanuring. Improper or insufficientmanuring results in weak plants.Manure is an organic substanceobtained from the decomposition ofplant or animal wastes. Farmers dumpplant and animal waste in pits at openplaces and allow it to decompose. Thedecomposition is caused by somemicroorganisms. The decomposedmatter is used as organic manure.Fertilisers are chemicals which arerich in a particular nutrient. How arethey different from manure? Fertilisersare produced in factories. Someexamples of fertilisers are— urea,ammoniumsulphate,superphosphate, potash, NPK (Nitrogen,Phosphorus, Potassium).The use of fertilisers has helpedfarmers to get better yield of cropssuch as wheat, paddy and maize. Butexcessive use of fertilisers has madethe soil less fertile. Fertilisers have alsobecome a source of water pollution.Therefore, in order to maintain thefertility of the soil, we have tosubstitute fertilisers with organicmanure or leave the field uncultivated(fallow) in between two crops.The use of manure improves soiltexture as well as its water retainingcapacity. It replenishes the soil withnutrients.Another method of replenishingthe soil with nutrients is through croprotation. This can be done by growingdifferent crops alternately. Earlier,farmers in northern India used togrow legumes as fodder in one seasonand wheat in the next season. Thishelped in the replenishment of the soilwith nitrogen. Farmers are beingencouraged to adopt this practice.
In the previous classes, you havelearnt about Rhizobium bacteria.These are present in the nodules ofroots of leguminous plants. They fixatmospheric nitrogen.Advantages of Manure: The organicmanure is considered better thanfertilisers. This is 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.
Que. 1) Organic substance obtained from the decomposition of plant and animal waste that helps in the healthy growth of plants are called:
(a) Fertilisers
(b) Chemicals
(c) Manure
(d) Cow dung
Que. 2) Excessive use of fertilisers is generally observed to …………………………………………………..……………………………………?
(a) Decrease the fertility of soil
(b) Increase the soil content
(c) Rise the amount of microbes
(d) Rise the amount of water in soil
Que. 3) Which of the following nitrogen fixing bacteria is present in the root nodules of leguminous plants?
(a) E. coli
(b) Rhizobium bacteria
(c) Archaebacteria
(d) Eubacteria
Que. 4) Write down some of the examples of commonly used fertilisers.
Que. 5) What do you understand by the term “crop rotation”? Give its importance.
Answer Key
Que. 1) (c) Manure
Que. 2) (a) Decrease the Fertility of soil
Que. 3) (b) Rhizobium bacteria
Que. 4) Answer: Some of the examples of fertilisers include: super phosphate, potash, NPK (Nitrogen, Phosphorus, Potassium), urea, ammonium sulphate.
Que. 5) Answer: Crop rotation is the process of growing different crops alternately. It is important because it replenishes the soil with nutrients.
Case study 5
All living beings need water to live.Water is important for proper growthand development. Water is absorbed bythe plant roots. Along with water,minerals and fertilisers are alsoabsorbed. Plants contain nearly 90%water. Water is essential becausegermination of seeds does not take placeunder dry conditions. Nutrientsdissolved in water are transported toeach part of the plant. Water alsoprotects the crop from both frost andhot air currents. To maintain themoisture of the soil for healthy cropgrowth, fields have to be wateredregularly.The supply of water to crops atregular intervals is called irrigation. Thetime and frequency of irrigation variesfrom crop to crop, soil to soil and seasonto season. In summer, the frequency ofwatering is higher. Why is it so? Couldit be due to the increased rate ofevaporation of water from the soil andthe leaves?Sources of irrigation: The sources ofwater for irrigation are— wells,tube wells, ponds, lakes, rivers, damsand canals.Traditional Methods ofIrrigationThe water available in wells,lakes and canals is lifted upby different methods indifferent regions, for taking itto the fields.Cattle or human labour isused in these methods. Sothese methods are cheaper,but less efficient. The varioustraditional ways are:(i) moat (pulley-system)(ii) chain pump(iii) dhekli, and(iv) rahat (Lever system).Pumps are commonlyused for lifting water. Diesel,biogas, electricity andsolar energy is used to runthese pumps.Modern Methods ofIrrigationModern methods of irrigationhelp us to use watereconomically.
The mainmethods used are as follows:(i) Sprinkler System: Thissystem is more useful on theuneven land where sufficientwater is not available. Theperpendicular pipes, havingrotating nozzles on top, arejoined to the main pipelineat regular intervals. Whenwater is allowed to flowthrough the main pipe under pressurewith the help of a pump, it escapes fromthe rotating nozzles. It gets sprinkledon the crop as if it is raining.Sprinkler is very useful for lawns, coffeeplantation and several other crops(ii) Drip system: In this system, thewater falls drop by drop directly nearthe roots. So, it is called drip system. Itis the best technique for watering fruitplants, gardens and trees.Water is not wasted at all. It is a boon inregions where availability of water is poor.
Que. 1) Which of the following is NOT an example of source of irrigation?
(a) Well
(b) Forest
(c) Canal
(d) Dams
Que. 2) Which one of the following examples is a traditional method of irrigation?
(a) Sprinkler
(b) Drip system
(c) Hose
(d) Dhekli
Que. 3) …………………………………………………………………………………. is used in uneven land where sufficient water is not available and has a rotating nozzle?
(a) Sprinkler system
(b) Pulley system
(c) Drip system
(d) Chain pump system
Que. 4) Why is irrigation important in crop cultivation?
Que. 5) Explain in detail about the drip irrigation system.
Answer Key
Que. 1) (b) Forest
Que. 2) (d) Dhekli
Que. 3) (a) Sprinkler system
Que. 4) Answer: Irrigation is the process of supplying water to crops at regular intervals. Irrigation is important for the proper growth and development of the plants. Along with water irrigation also helps absorb minerals and fertilisers and also helps in the germination of seeds.
Que. 5) Answer: In the drip irrigation system, water falls drop by drop directly near the roots. It is considered to be a best technique for watering fruit plants, gardens and trees. It reduces wastage of water and ideal for places with poor availability of water.
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