Only Agriculture

  Characteristics of weeds  Weeds are also like other plants but have unique characteristics that tend to put them in the   classification of unwanted plants.   • Most weeds especially annuals produce an enormous quantity of seeds, e.g. wild   oats (Avena fatua), which have a million  roots. It has been observed that among 61 perennial   weeds, the average seed-production capacity was 26,500 per plant.   • Weeds can resist 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 unfavorable soil-moisture conditions, have a short   span of plant growth, naturally grow faster rate and produce seeds earlier than most of   the crops growing in the association. Weed seeds remain viable for longer periods without losing their viability, e.g. annual   meadow grass (Poa annua) and scarlet pimpernel (Anagallis arvensis) remain viable for   about 8 years; creeping thistle (Cirs

 WEEDS--BENEFICIAL AND HARMFUL 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-  the operation, in partnerships