NCERT Class-9 Science Solutions: Chapter 15-Improvement In Food Resources Part 8

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Question 41:

What do you understand by composite fish culture?


Composite fish culture is the method to culture five or six species, both indigenous and exotic, together in a single fish pond. These species are selected so that they do not compete for food among themselves having different types of food habits. As a result food available in all the parts of the pond is used. For example - Catlas are surface feeders, Rohu is middle zone feeder and Mrigals and common carps are bottom feeders.

Image the composite fish culture

Image the Composite Fish Culture

Question 42:

Why bee keeping should be done in good pasturage?


The quality and taste of honey depends upon the flora, pasturage or orchards available for the nectar and pollen collection. That is bee keeping should be done in good pasturage. Pasturage/orchard flora of honey bees include a variety of flowering plants such as mango (Aam), coconut (Narial), almond (Badam) tamarind (Imli), ber, berseem, litchi, cotton, shishame, apple, mahua, coriander, cashew, coffee, rubber plants, guava, sunflower, neem, etc.

Image bee in good pasturage

Image Bee in Good Pasturage

Question 43:

Write the modes by which insects affect the crop yield.


Some common insect pests of stored grain and their mode of infection are

  1. Gram dhora or Pulse beetle (Callosobruchus maculates) Its grubs, damage the stored gram

  2. Rice weevil (Sitophilus oryza) Both grub and beetle (adult) damage rice

  3. Khapra or Wheat weevil (Trogoderma granarium) Infests stored wheat

  4. Grain and flour moth (Sitotroga cerealella) Its caterpillars bore into grains of rice, wheat, barley, maize and jowa

  5. Rust red flour beetle (Tribolium castaneum) Both larvae and adult damage flour and flour products

  6. Rice moth (Corcyra cephalonica) Larvae damage rice and maize

  7. Lesser grain borer (Rhizopertha dominica) Both grub and adult (beetle) damage the grains, reducing them to perforated shells

Question 44:

Discuss why pesticides are used in very accurate concentration and in very appropriate manner?


Pesticides are used in very accurate concentration and in a very appropriate manner, because if used in excess it

  1. Harms the soil and causes loss of fertility

  2. Checks the replenishment of organic matter

  3. Kills the microorganism of soil

  4. Causes air, water and soil pollution

Question 45:

Name two types of animal feed and write their functions.


The dairy cattle is given a balanced ration, which contains all nutrients in proportionate amounts. A ration is the amount of food which is given to the animal during a twenty-four hour period.

The animal feed includes two types of substances

  1. Roughage it largely contains fibers such as green fodder, silage, hay (straw of serials) and legumes, (e.g., berseem, Lucerne, cow pea and agathi)

  2. Concentrates The concentrates used in feed of cattle and buffaloes are a mixture of substances which are rich in one or more of the nutrients, g., cotton seeds, oil seeds, grains of maize, oats, barley jowar, bajra, gram and their byproducts such as wheat bran, rice bran (polish), gram husk, oil seed cakes and molasses.

  3. Green fodder and dry grasses (roughage)

  4. Grain mixture (concentrates)

  5. Water 30 to 35 liters.

Besides above mentioned nutritious food material, dairy animals require certain additive feeds, promote the growth of the animals which contain antibiotic, minerals, and hormones, facilitate good yield of milk and protects them from diseases.

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