|Definition and Characteristics, Properties of weed.
Definition and Characteristics of weeds
Definition of Weed:
· A plant which is prolific of persistence in nature and whose potentialities for harm are greater than their potentialities for good.
· A plant growing where it is not desired/unwanted particularly where man is attempting to grow a crop. (Shaw – 1956).
· Any unwanted plant is called weed.
· A plant that grows spontaneously in a habitat that has been greatly modified by human action. (Harper 1944).
· A useless, undesirable and often very unsightly plant of wild growth usually found in land which has been cultivated or in areas developed by man for specific purposes other than cultivation. (Thomas 1956).
· Weed may be defined as good nutrient absorbing competitor plant which grows out of place spontaneously and possess the characteristics of plentiful growth and reproduction even under adverse condition.
Characteristics/Properties of weed:
1. The prime characteristics possessed by all important weeds is their ability to thrive under adverse condition.
2. A number of weeds can spread/propagate by vegetative methods even if they are prevented from producing seeds.
3. Large number of seeds are produced by weeds every year. Eg. Wormwood weed produces 1 million seeds per year (weeds of Amaranthus family produces large no. of seed).
4. Weed seeds remain viable for many years in soil.
5. Dispersion capacity of weed seed is diverse.
6. Eradication is difficult.
7. Nutrient uptake capacity of weed is high.
8. Many weeds successfully compete with cultivated crops.
9. They can grow well in nitrogen deficient soil.
10. They are resistant to disease and insect.
11. Some weed seeds are very difficult to separate from crop seeds because of their similarity size and shape.
12. Weeds are frequently capable of growing within a very short period of time.