Reasons why weeds are more successful than field crops
(i) They produce very many viable seeds that can germinate even when they are immature e.g Black jack, devel’s hose whip, Lantana
(ii) They have a faster growth rate which makes them outgrow crops e.g star grass
(iii) They are highly resistant to pests and diseases that attack crops e.g most weeds are less palatable to pests
(iv) They grow in all types of soils and can easily survive on few Nutrients e.g spear grass, Oxalis, Nut grass
(v) Some weeds are Allelopathic ie they produce substances that make plants difficult to grow around them, a condition called Allelopathy
(vi) Most weeds have perennating organs which are used to produce new plants e.g Rhizomes for Rhizomes for spear grass, Bulbils for Oxalis
(vii) They have different dispersal mechanisms which are effective e.g – self explosive mechanisms, hard seed coats, presence of hooks on their seeds.
(viii) They are resistant to harsh conditions ie Ability to remain domant in the dry season and sprout out as soon as rain season starts e.g Coach grass and spear grass.