Sunday, April 7, 2013

8th Crops Production and Management Check point [Formative]

Book Reading Science Power class 8th SRIJAN publications

Check point -01[Formative]
Q. Why cotton or rice cannot be grown in winter or wheat in rainy seasons?

Answer:  Cotton or rice cannot be grown in winter as they require lot of water where as  wheat cannot be grown in rainy seasons as they need much less rain and low temperature.
Q. Name the main cereal crops grown in India?

Answer: Rice, wheat, maize etc. are the main cereal crops grown in India.

Q. Name the crops seasons in India .Why do we have different crops seasons?

Answer: Rainy season(Kharif crops) and winter season (Rabi crops)are two main crops seasons in India. We have different crops seasons as different crops required different climatic conditions like temperature, humidity and rainfall.

Q. Give reason why Kharif crops cannot be grown in Rabi season?

Answer: Kharif crops cannot be grown in Rabi season because they need lot of water.

Q. Name three crops plants grown in Kharif seasons.

Answer: Paddy, maize, bajra.

Q. What are the important aspects of getting a bumper crops?

Answer: Following are the important aspects of getting a bumper crops:
 (i) Preparation of soil                 
 (ii) selection and sowing seeds    (iii) Adding manure and fertilizers
(iv) Irrigation                               (v) Protecting from weeds, pets and diseases 
(VI) Harvesting                          (vii) Storage

Q. Give two advantage of plowing field?

Answer: The two advantage of plowing field are:
 (i) to allow the roots to penetrate deep into the soil
(ii) To increase the growth of earthworms and microbes in soil

Q. Why is leveling essential?

Answer: leveling essential 
(i) to prevent the loss of moisture from ploughed field   
(ii) to prevent water logging in field (iii) to prevent loss of the upper layer of soil

Check point -02[Formative]

Q. Why we need to keep proper distance between seeds?

Answer: This help to get enough sunlight, water and nutrients by preventing overcrowding in field.

Q. Name the three steps involve in soil preparation.

Answer: The three steps involve in soil preparation are ploughing, levelling and manuring.

Q. Name the medium in which plants grow.

Answer: Soil is the medium in which plants grow.

Q. Why is ploughing is essential. Give two reasons?

Answer: Ploughing is essential for turning and loosening the soil and increase water holding capacity.

Q. Sowing with seed drill is better. Give two reasons?

Answer: Seed drill sows the seeds uniformly at proper distances and depths. It ensures that seeds get covered by the soil after sowing. A seed drill also saves time and labor.

Q. What is transplantation?

Answer: The practice of transferring seedling from nursery to main field is called transplantation.

Check point -03[Formative]

Q. Name the two fertilizers containing nitrogen and other containing phosphorous?

Answer: The two fertilizers containing nitrogen are urea(CH4N2O) and ammonium sulphate [(NH4)2SO4] and The two fertilizers containing phosphorous are ammonium hydrogen  Phosphate  and ammonium Phosphate [(NH4)2HPO4]

Q. How is compost prepared?

Answer: compost is prepared from the decomposition of vegetable waste, farm and kitchen waste by the action of soil bacteria.

Q. What are bio fertilizers?

Answer: A biofertilizer is a substance which contains living microorganisms like Azobacter and micorrhiza.

Q. What is the use of field fallowing?

Answer: fallowing means leaving field to rest for a season this helps to improve soil fertility.

Q. Explain the significance of crop rotation or mixed cropping?

Answer: The practice of growing different crops alternately in a field is called crop rotation like pulses that are grown between two cereals. The practice of growing two or more types of crops in the field is called mixed cropping. These help in the replenishment of the soil with nutrients.

Check point -04[Formative]

Q. Why fields need to be irrigated before sowing seeds?

Answer: To maintain moisture in soil for seed germination

Q. Why should seeds be shown in moist soil?

Answer: Moist soil helps in proper germination and growth of seeds.

Q. Why drip irrigation is better than other method of irrigation?

Answer: This is because, in drip system, the water falls drop by drop just at the position of the roots and there is no wastage of water. It is a boon in the regions where availability of water is poor.

Q. Why excessive irrigation harmful to the crops?

Answer: Excessive irrigation cuts off oxygen supply to roots of plants that prevent proper growth of plants. Excessive irrigation also increase amount of salt in soil that reduces fertility of soil.

Check point -05[Formative]

Q. What are weeds? How do they effect crops?

Answer: The undesirable plants that grown naturally along with the crop in a field are called weeds. For example: Amaranthus, Wild Oat (javi), Chenopodium (bathua). Weeds compete with the crop plants for water, nutrients, space and light. Thus, they affect the growth of the crop.

Q. Give one difference and one similarity between weedicides and insecticides?

Answer: weedicides kill weeds where as insecticides kill insects. Both weedicides and insecticides are sprayed standing crops before flowering and fruiting.

Q. Differentiate between insecticides and pesticides?

Answer: insecticides kill insects where as pesticides kill pests and their eggs.

Q. Name the methods used for pest eradication.

Answer: By chemical control and by biological control

Q. What are the harmful effects of using insecticides or pesticides?

Answer: Insecticides and pesticides contain very harmful chemicals which cause harmful effect on human health, pollute soil and water and also kill useful insects.

Q. What is organic farming? Why should we opt for it?

Answer: The method of farming in which organic manure and biological methods for controlling pets are used is called organic farming.  We opt for it to reduce effect of chemical fertilizer on the soil.

 Check point -06[Formative]

Q. How is cross breading carried out in plants?

Answer: At first anthers are removed [Emasculation] from one plant and pollen grain of another flower are transferred to stigma of first flower and covered with plastic bag till seeds formed.

Q. What is harvesting?

Answer:  The cutting and gathering of crops after it is matured is called harvesting.

Q. Give the name of two crops harvested manually.

Answer: Rice and wheat

Q. Name the machine used for both harvesting and threshing.

Answer: combine

Q. Name the process of separating grain from harvested crops.

Answer: Thressing

Q. Why is threshing essential?

Answer: This is because threshing separates grain and husk from harvested crops.

Q. What do you mean by green revolution?

Answer: The combined efforts that result in increase in food production by using new techniques that made our country self sufficient in food grain production is called green revolution.

Q. Name the scientist whose efforts resulted in the success of green revolution.

Answer: M.S. Swaminathan

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