Theory question 105
Weeds and Weed Control(a) Define the term weed.
(b) Describe four methods of weed control.
(c) Give six reasons for controlling weeds on the farm.
Show the model answer
(a) A weed is any plant growing where it is not wanted
(b) Any four: physical/mechanical – hand pulling, hoeing, slashing, mowing, tillage; cultural – crop rotation, mulching, cover crops, close spacing, timely planting; chemical – herbicides (pre- or post-emergence); biological – using insects, animals or diseases that attack weeds; burning; flooding
(c) Any six: weeds compete with crops for nutrients, water and light; reduce yield; harbour pests and diseases; some are poisonous to livestock; some are parasitic (striga); reduce quality of produce; make harvesting difficult; increase cost of production; block irrigation channels
Explain how each control method works.