WEEDS – HARMFUL AND BENIFICIAL EFFECTS
Weeds are plants that are unwanted in a given situation and may be harmful, dangerous
or economically detrimental. Weeds are a serious threat to primary production and biodiversity.
They reduce farm and forest productivity, displace native species and contribute significantly to
land and water degradation. The costs of weeds to the natural environment are also high, with
weed invasion being ranked second only to habitat loss in causing biodiversity decline.
Despite considerable government and private sector investment, weed invasion still
represents a major threat to both the productive capacity of land and water and the integrity of
our natural ecosystems. An efficient weed control program can only be developed after the
weed has been properly identified. Weeds can be managed using many different methods. The
most effective management of weeds is usually achieved through collaboration and co-
operation, in partnerships between the community, land owners, agriculture, industry and the
various levels of government, using a combination of methods in conjunction with a thorough
follow-up campaign.
Weed management is an important component of plant protection improving the
production potential of crops. It includes management of the weeds in a way that the crop
sustains its production potential without being harmed by the weeds. Weed management is
done through the mechanical, cultural and chemical means. Use of biological control methods in
field crops is being considered, but still not much in use. Use of herbicides is an important
method in the modern concept of much in use. Use of herbicides is an important method in the
modern concept of weed-management technology. New hand-tools and implements have also
been designed to assist in wed-management programme.
Characteristics of weeds
Weeds are also like other plants but have special characteristics that tend to put them in the
category of unwanted plants.
• Most of the weeds especially annuals produce enormous quantity of seeds, e.g. wild
oats (Avena fatua), produces 250 seeds per plant, whereas wild amaranth (Amaranthus
viridis) produces nearly 11 million seeds. It has been observed that among 61 perennial
weeds, the average seed-production capacity was 26,500 per plant.
• Weeds have the capacity to withstand adverse conditions in the field, because they can
modify their seed production and growth according to the availability of moisture and
temperature. They can germinate under adverse soil-moisture conditions, have short
period of plant growth, generally grow faster rate and produce seed earlier than most of
the crops growing in association.
Weeds are plants that are unwanted in a given situation and may be harmful, dangerous
or economically detrimental. Weeds are a serious threat to primary production and biodiversity.
They reduce farm and forest productivity, displace native species and contribute significantly to
land and water degradation. The costs of weeds to the natural environment are also high, with
weed invasion being ranked second only to habitat loss in causing biodiversity decline.
Despite considerable government and private sector investment, weed invasion still
represents a major threat to both the productive capacity of land and water and the integrity of
our natural ecosystems. An efficient weed control program can only be developed after the
weed has been properly identified. Weeds can be managed using many different methods. The
most effective management of weeds is usually achieved through collaboration and co-
operation, in partnerships between the community, land owners, agriculture, industry and the
various levels of government, using a combination of methods in conjunction with a thorough
follow-up campaign.
Weed management is an important component of plant protection improving the
production potential of crops. It includes management of the weeds in a way that the crop
sustains its production potential without being harmed by the weeds. Weed management is
done through the mechanical, cultural and chemical means. Use of biological control methods in
field crops is being considered, but still not much in use. Use of herbicides is an important
method in the modern concept of much in use. Use of herbicides is an important method in the
modern concept of weed-management technology. New hand-tools and implements have also
been designed to assist in wed-management programme.
Characteristics of weeds
Weeds are also like other plants but have special characteristics that tend to put them in the
category of unwanted plants.
• Most of the weeds especially annuals produce enormous quantity of seeds, e.g. wild
oats (Avena fatua), produces 250 seeds per plant, whereas wild amaranth (Amaranthus
viridis) produces nearly 11 million seeds. It has been observed that among 61 perennial
weeds, the average seed-production capacity was 26,500 per plant.
• Weeds have the capacity to withstand adverse conditions in the field, because they can
modify their seed production and growth according to the availability of moisture and
temperature. They can germinate under adverse soil-moisture conditions, have short
period of plant growth, generally grow faster rate and produce seed earlier than most of
the crops growing in association.
