The bigger part of crop farming seems to be a constant physical war between the farmer and weeds. Agriculturalists describe a weed as a plant growing where it should not be. It does not matter whether the plant growing where it is not wanted is edible or even good looking. As long as it is misplaced, it is a weed, and the farmer has to remove it to stop its pressure on the desired crops.
If, for example, a tobacco plant grows in a bean garden, it competes with the beans for basic ground resources such as water, soil nutrients, sunlight, and growing space. If its leaves are dropped in the field they could get mixed with those of the desired crop growing in the same field and introduce the tobacco smell into the harvested crop. The dry weeds and even seeds may be difficult to separate from those of the harvested dry crops.
Weeds reduce the quality of crop products. They lower crop yields and, if not suppressed in time, they can take over the entire crop field and make it difficult for the farmer to use it again for crop production.Yet fighting weeds takes up time and money, thus reducing profits. To fight the weeds, the farmer may have to hire more labourers or to buy herbicides. Herbicides are poisons that kill weeds but if not carefully handled, the chemicals may be harmful to the crops, the farmer, and the consumers.
Simple weed control measures include planting early, almost as soon as ground preparation is done, so that by the time the weed seeds begin to germinate, the crops will already be strong and well established. In such circumstances it will be the crops to suppress the weeds. It is also good to plant crop seeds according to the recommended rates and spacing. If there are very wide gaps between the crops, there will be plenty of space for the weeds to grow in. Some people burn the weeds after uprooting them so that they are destroyed together with their seeds.
Another effective way to fight weeds is to cover the ground with grass or dry plant leaves in what is commonly referred to as mulching. The grass used should be the type that does not quickly sprout or easily cast its seed. When the ground is all covered, up weeds have no space in which to grow.