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NCERT Exemplar · Class 9 Science Improvement in Food Resources

49 questions · 49 still being checked

Short Answer Questions 28–35 (part 4 of 6)

  1. Exercise 28

    Define the term hybridization and photoperiod.

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    NCERT’s answer
    Hybridisation— Hybridisation refers to crossing between genetically dissimilar organisms. Photoperiod— Duration of sunlight available to the plant is called as photoperiod. It affects the growth, flowering and maturation of crops.
    Hybridization: crossing genetically dissimilar plants (same or different species/genus) to combine desirable characters in one plant. Photoperiod: the duration of sunlight a plant is exposed to daily; it controls flowering.Answer: Hybridization = crossing dissimilar parents for combined traits; photoperiod = daily sunlight duration controlling flowering.

  2. Exercise 29

    Fill in the blanks
    (a)
    Photoperiod affect the————.
    (b)
    Kharif crops are cultivated from————to————.
    (c)
    Rabi crops are cultivated from————to————.
    (d)
    Paddy, maize, green gram and black gram are————crops.
    (e)
    Wheat, gram, pea, mustard are————crops.

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    NCERT’s answer
    (a)
    Flowering of plants (b) June to October (c) November to April (d) Kharif (e) Rabi
    (a)
    Photoperiod affects the flowering.
    (b)
    Kharif crops are cultivated from June to October.
    (c)
    Rabi crops are cultivated from November to April.
    (d)
    Paddy, maize, green gram and black gram are kharif crops.
    (e)
    Wheat, gram, pea, mustard are rabi crops.
    Answer: (a) flowering (b) June-October (c) November-April (d) kharif (e) rabi

  3. Exercise 30

    Cultivation practices and crop yield are related to environmental condition. Explain.

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    NCERT’s answer
    Different crops and cultivation practices require different climatic conditions, temperature, photoperiod for their growth and completion of life cycle. There are some crops which are grown in rainy season (Kharif crops) while some others are grown during winter season (Rabi crops).
    Each crop needs a specific climate window — temperature, day-length, water — so practice must track it: kharif crops (paddy, maize, soyabean) suit the hot, wet monsoon; rabi crops (wheat, gram, mustard) suit the cool, dry winter. Sowing, irrigation and variety choice must match it, or yield falls.Answer: Kharif crops need a hot, wet monsoon season; rabi crops need a cool, dry winter season — practice must match this pattern.

  4. Exercise 31

    Fill in the blanks
    (a)
    A total of———nutrients are essential to plants.
    (b)
    ———and———are supplied by air to plants.
    (c)
    ———is supplied by water to plants.
    (d)
    Soil supply———nutrients to plants.
    (e)
    ———nutrients are required in large quantity and called as———.
    (f)
    ——— nutrients are needed in small quantity for plants and are
    called ———.

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    NCERT’s answer
    (a)
    $\displaystyle 16$ (b) Carbon and Oxygen (c) Hydrogen (d) 13. (e) Six, macronutrients (f) seven, micronutrients
    (a)
    $\displaystyle 16$ nutrients are essential to plants.
    (b)
    Carbon and Oxygen are supplied by air.
    (c)
    Hydrogen is supplied by water.
    (d)
    Soil supplies $\displaystyle 13$ nutrients.
    (e)
    Six nutrients are required in large quantity and are called macronutrients: \(\displaystyle \text{N, P, K, Ca, Mg, S}\).
    (f)
    Seven nutrients are needed in small quantity and are called micronutrients: \(\displaystyle \text{Fe, Mn, Zn, Cu, B, Mo, Cl}\).
    Answer: (a) $\displaystyle 16$ (b) carbon, oxygen (c) hydrogen (d) $\displaystyle 13$ (e) six; macronutrients (f) seven; micronutrients

  5. Exercise 32

    Differentiate between compost and vermicompost?

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    NCERT’s answer
    Compost— Compost formation is the process in which farm waste materials like livestock excreta, vegetable wastes, animal refuse, domestic waste, straw, eradicated weeds are decomposed and used as manure. Vermicompost— The compost prepared from organic matter by using earthworm which hastens the process of decomposition.
    Compost: farm/animal/kitchen waste piled in pits, left to rot slowly by natural microbial decomposition; takes months, no earthworms used. Vermicompost: the same waste is decomposed with earthworms added to the pit, which speed the process into nutrient-rich manure within weeks.Answer: Compost rots by microbes alone over months; vermicompost uses earthworms to do it faster.

  6. Exercise 33

    Arrange these statements in correct sequence of preparation of green
    manure.
    (a)
    Green plants are decomposed in soil.
    (b)
    Green plants are cultivated for preparing manure or crop plant parts
    are used.
    (c)
    Plants are ploughed and mixed into the soil.
    (d)
    After decomposition it becomes green manure.

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    NCERT’s answer
    (b)
    → (c) → (a) → (d)
    Manure crop must grow before it is ploughed in and left to rot: (b) cultivate green plants (or use crop-plant parts) for manure → (c) plough and mix into soil → (a) decompose in soil → (d) obtain green manure.Answer: (b) → (c) → (a) → (d)

  7. Exercise 34

    An Italian bee variety A. mellifera has been introduced in India for honey production. Write about its merits over other varieties.

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    NCERT’s answer
    Merits of Italian bee variety A. mellifera are— (a) It stings less. (b) It has high honey collection capacity. (c) It stays in given bee-hive for long periods and breeds very well.
    Apis mellifera, reared in movable-frame hives, out-performs the local A. cerana indica, A. dorsata and A. florea:
    higher honey yield per colony
    gentler, stings less on handling
    non-migratory, does not abscond the hive
    breeds well, so colonies multiply fast
    Answer: Higher honey yield, gentle temperament, non-migratory habit and fast breeding make it preferred for apiculture.

  8. Exercise 35

    In agricultural practices, higher input gives higher yield. Discuss how?

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    NCERT’s answer
    In agricultural practices, higher input gives higher yield. This means higher money input to raise the yield. Financial conditions of the farmers allows them to take up different farming practices and technologies. The farmer’s purchasing capacity for input decides cropping system and production practices.
    Higher input here means higher MONEY input: a farmer's purchasing capacity decides which inputs are bought, and that decides the cropping system.\[\text{purchasing power}\uparrow \Rightarrow \text{HYV seed, irrigation, fertiliser, pest control bought} \Rightarrow \text{yield}\uparrow \]Answer: Higher money input raises purchasing capacity, which decides the production practice (no-cost, low-cost or high-cost) a farmer adopts — better seed, irrigation, fertiliser and pest control raise yield.