Class 9 Biology Improvement Food Resources Weeds


The unwanted plants that grow by their own in the cultivating fields and compete with required crops for food, light, space and essential nutrients present in the soil are called weeds.

For example, Parthenium (gajar ghas), Cyperinus rotundus (motha).

As they compete with all necessary requirements for growth of a plant they end up affecting the growth of the required crop plants.

To ensure good harvest they must be removed from the fields to be used for cultivation, before sowing the required crops.

Weeds, insects and pests that affect the growth of crop plants can be controlled by using herbicides, insecticides and fungicides by spraying them on the crops.

Weeds can also be removed by cutting them down.

Some other methods to prevent growth of weeds are:

  • Proper seed bed preparation.
  • Timely sowing of crops.
  • Inter cropping and croprotation.
  • Use of resistant varieties.
  • Summer ploughing in which fields are ploughed deep in summers to ensure removal of weeds and pests

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