Weeding
Weeds are any unwanted plant. For example, watermelon growing in a cabbage farm can be a weed. A farmer that has Watermelons growing on his Cabbage fame will consider the watermelons as weeds.
The farmer can remove the watermelon plants from the farm using a cutlass, weedicides, pulling them out with his hand etc.
Importance of weeding
It increases crop yield because it prevents competition between the unwanted crops and wanted crops for soil nutrients, sunlight etc.
It allows free movement of air among the wanted crops in the farm.