What are weeds? Name any one weed found in a crop field.

Weeds are unwanted plants that grow alongside cultivated crops in agricultural fields, competing with them for essential resources such as nutrients, water, sunlight, and space. These undesirable plants emerge naturally from seeds already present in the soil or introduced through wind, water, animals, or contaminated inputs, and they can significantly reduce crop yields by interfering with crop growth and development. Weeds also serve as hosts for various pests and diseases that can subsequently attack the main crop, create harvesting difficulties, reduce produce quality, and increase production costs through the need for control measures.

One common weed found in crop fields is Chenopodium album, commonly known as bathua or pigweed, which frequently appears in wheat, mustard, and vegetable fields. Other examples include Cynodon dactylon (doob grass or Bermuda grass) in various crops, Parthenium hysterophorus (congress grass or carrot weed) in fallow lands and field margins, wild oats in wheat fields, and Echinochloa species (barnyard grass) in rice paddies. Effective weed management through timely removal, proper cultural practices, mulching, or selective herbicide use is crucial for maintaining optimal crop productivity and preventing yield losses that can range from 10% to over 50% depending on weed density and crop type.