Study Materials

NCERT Solutions for Class 9th Science


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Chapter 15. Improvement in Food Resources

Chapter Review




Q – Write the  major groups of activities for crop yield can be classified?

A - the major groups of activities for improving crop yields can be classified as:

• Crop variety improvement

• Crop production improvement

• Crop protection management.

Q – Write about manure ?

A - Manure contains large quantities of organic matter and also supplies small quantities of nutrients to the soil. Manure is prepared by the decomposition of animal excreta and plant waste.

Q – write about fertilizer ?

A -  Fertilizers are commercially produced plant nutrients. Fertilizers supply nitrogen, phosphorus and potassium. They are used to ensure good vegetative growth (leaves, branches and flowers), giving rise to healthy plants. Fertilizers are a factor in the higher yields of high-cost farming.

Q – Write the use of manure?

A –

  1. Manure helps in enriching soil with nutrients and organic matter and increasing soil fertility
  2. The bulk of organic matter in manure helps in improving the soil structure.
  3. This involves increasing the water holding capacity in sandy soils.

Q – How many type of manure can be classified?
A -  manure can be classified as:

  1.  Compost The process in which farm waste material like livestock excreta (cow dung etc.), vegetable waste, animal refuse, domestic waste, sewage waste, straw, eradicated weeds etc. is decomposed in pits is known as composting.
  2. vermi-compost: The compost is rich in organic matter and nutrients. Compost is also prepared by using earthworms to hasten the process of decomposition of plant and animal refuse. This is called vermicompost.
  3. Green manure: the sowing of the crop seeds, some plants like sun hemp or guar are grown and then mulched by ploughing them into the soil. These green plants thus turn into green manure which helps in enriching the soil in nitrogen and phosphorus.

Que: What is green revolution?

Ans : There have increased food grain production by applying the scientific technique, modern agriculture instruments and hybrid seeds. This is known as green revolution.

Que: What is white revolution?

Ans: By applying the scientific technique, there have been excessive increasing in milk production this is known as white revolution.

Que:  What types of cropping patterns should apply to increase the income or more productivity?


  1.  Mixed cropping
  2. Inter-cropping
  3. Crop rotation

Que: By which the silver revolution belongs to?

Ans: Increased poultry production.

Que: write the different between Ravi and Kharif crops.

Ans :

Ravi Crops

Kharif crops

  1. These crops are grown from November to April.
  2. Ex: Wheat, gram, pea and mustard etc.
  1. These crops are grown from June to October.
  2. Ex: Paddy, cotton, soyabean and maize etc.  


Que : Define Hybridisation ?

Ans : The crossing between genetically dissimilar plants to produce a new type of plant (hybrid) is called hybridization.

Que : What are weeds?

Ans : Weeds are unwanted plants which grow along with the crops.

Que : Write the two methods of weed control.

Ans :

  1. Physical methods – Hand weeding, tilling, mowing and buring.

Que : What are macro-nutrients?

A - There are sixteen nutrients which are essential for plants. Air

supplies carbon and oxygen, hydrogen comes from water, and soil supplies the other thirteen nutrients to plants. Amongst these

thirteen nutrients, six are required in large quantities and are therefore called macronutrients.

Q – What is mixed cropping?

A - Mixed cropping is growing two or more crops simultaneously on the same piece of land, for example, wheat + gram, or wheat + mustard, or groundnut + sunflower.

Q – Define inter-cropping.

A – Inter-cropping is growing two or more crops simultaneously on the same field in a definite pattern.

Q – Define crop-rotation?

A - The growing of different crops on a piece of land in a pre-planned succession is known as crop rotation.

Q – In What way insect pests attack the plants?

A – Generally insect pests attack the plants in three ways:

  1.  They cut the root, stem and leaf,
  2. They suck the cell sap from various parts of the plant.
  3. They bore into stem and fruits.


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