MP Board · Class 9 · Science · Improvement in Food ResourcesWhat are weeds? Give two common examples of weeds found in crop fields. Describe three preventive and control measures used to manage weed growth and protect crop yield.

Weeds Definition:\nWeeds are unwanted and undesirable plants that grow alongside cultivated crops in agricultural fields. They compete with main crop plants for essential resources such as light, nutrients, water, and space, thereby significantly reducing crop growth and overall yield.

Examples of Weeds:

1. Xanthium (Gokhroo)
2. Parthenium (Gaji Ghas / Carrot grass)
3. Cyperinus rotundus (Motha)

Control and Preventive Measures:

1. Mechanical Removal: Physical removal of weeds by uprooting or cutting them manually using hands or agricultural tools like a trowel (khurpi) before they flower and produce seeds.
2. Chemical Control: Spraying specific chemical substances called herbicides or weedicides (such as 2,4-D) that selectively kill weeds without damaging the main agricultural crops.
3. Cultural Methods: Adopting preventive farming practices such as proper seedbed preparation, timely sowing of crops, intercropping, and proper crop rotation to suppress weed germination naturally.