What are weeds? Enlist the methods employed to control weeds

What are weeds? Enlist the methods employed to control weeds.
Or
Discuss various methods for weed control.
Answer:
The unwanted plants in a cultivated field are called weeds. They compete for food, space and light with the main crop plants. They germinate and grow faster, and thus effect the quality and yield of the crop. For these reasons, weed plants need to be removed from the cultivated field in early stage of crop.
The methods employed for weed control are as follows:

Mechanical Method: The weed plants are removed from the field either manually or with the help of agricultural implements like uprooting or hand hoeing or weeding with khurpi, ploughing, etc.

Cultural Method: This method includes:

  • Proper seed bed preparation
  • Timely sowing of crops
  • Intercropping
  • Crop rotation

Chemical Methods: By Spraying chemicals that do not harm crop plants but destroy only the weed plants, the latter can be controlled. These chemicals are called weeclicides, e.g., 2, 4-D and atrazine.
Biological Method: As we know, some insects feed an particular weeds. Thus, we use these insects as biological weed-controlling agents like the use of cochineal insect to control Opuntia weed and the use of the grass carp fish to control aquatic weeds.