Characteristics of weeds and factors for their spread

If today's farmer has any problem that is constantly plaguing the standing crop at the time of sowing and after sowing, it is the weeds that are growing in the crop, hindering the farm work and reducing the yield.  Before weed control, if the farmer is aware of how weed spreads and the special features of weed growth, then the decline in crop yield can be prevented by effectively preventing weed spread in the field.  Wind, water, manure, compost manure, man, livestock, farm implements, non-certified seeds purchased at the time of sowing of crops and use of water passing through the weedy area as irrigation etc. once acts as a weed spread agent.  After entering the field, in favorable or unfavorable conditions, weeds assert their rights in the field and become stubborn.  The prevalence of weeds is increasing due to some special features of weeds.

Characteristics of seed production and seed germination:

Weeds with an annual life cycle are capable of producing abundant seeds. Weeds grow and infest under any favorable conditions in any season as they have tremendous perennial power and can sustain perennials for years.

Power to produce more seeds:

Weeds have the power to produce a very large number of seeds on a single plant, a few examples of which are given below.

Dormancy of weed seeds

Weed seeds have three different types of dormancy.

(1) Longevity of seeds buried in the ground It is a common fact that seeds buried in the ground retain their viability for 10 years or more.  E.g.  Chili seeds have a germination rate of 38% even after 7 years.

(2) Some weed seeds remain dormant under adverse conditions and germinate only when conditions are favorable.  Weeds survive even in bad climates.  E.g.  Wakumba seeds.

(3) Some weed seeds are genetically dormant and cannot grow immediately.  E.g.  Wild oats.

Ability to produce seeds quickly

In most weeds, up to 20% of the seeds are mature by 50% flowering, while some weeds have the power to complete seed production even if the seedlings are picked up and kept in the shade before they mature.  E.g.  Salt.  Also special is the fact that weeds can produce seeds by shortening their life cycle in adverse climates even before they mature.  E.g.  Chil plants under normal conditions can grow up to 30 cm.  Or larger, when in adverse conditions 3 cm.  Produces seeds even at low altitudes.  Given the fact that the weed deceives farmers in the process of producing its seeds.

Power of vegetative growth:

Some weeds produce new plants easily from vegetative parts.  E.g.  Rhizome, Tuber, Wild Onion, Sucker and Root Stocks .

If the above weeds of the above weeds are cut off, new plants easily emerge from the existing part of the soil.

Characteristics for spreading:

Through wind, water, animals and birds, farm implements, seeds and organic fertilizers, weed seeds spread rapidly in different areas where they find favorable conditions for growth.  It is very difficult to prevent weeds from spreading through the wind.  The seeds of such weeds have a special structure so that they can be easily blown by the wind and moved from one place to another.

Often farmers unknowingly use harvested weeds as green or dry fodder for their livestock.  Most of these weed seeds are excreted in animal manure without losing vigor.  If this manure is not properly applied, the weed seeds come to the field through compost.

Weed seeds like wild paddy and immortelle are mixed with paddy and rajka seeds respectively and come to the field through the seeds.

Some weeds are spread by humans.  Initially man grows it for its specific use but later spreads it in the surrounding area without any precaution.  E.g.  Lanterns and hyacinths were brought into the country as ornamental plants, but in the forests and non-crop areas of the lanterns, weeds have become a nuisance and hyacinths are becoming difficult to control in lakes and confined waters.

Inherited adversity:

Most weeds survive natural disasters such as lack of moisture, more heat, frost as well as more salts in soil and water, lack of nutrients, etc. and complete their life cycle.  because ...

• Weed roots are usually stronger and more abundant than crop roots.
• Weeds can shorten their life cycle in adverse conditions.
• Weeds have the ability to dormant under adverse conditions and fast breeding under favorable conditions.
• There is no need for soil preparation or fertilizer for weeds to grow easily anywhere.

Variation in the number of different weeds:

There are about 30,000 species of weeds.  There are many well-known species of this species that can easily grow in different conditions.  Thus if the condition of one place is unfavorable for one species of weed then it is favorable for another species.

The appearance and taste of weeds

Many weeds escape from damage or eating by animals due to their bad taste, odor or thorns.  While some weeds escape human control due to their appearance and shape similar to their main crop.  E.g.  Bunt in paddy field, cumin in cumin field, gullidanda in wheat field and onion in onion field.

Given the above fact, it is clear that weeds escape or survive against various weed control measures tried by humans through naturally occurring systems.  Weed-free farming is therefore difficult, but it is important to think in terms of how weeds can be managed to the extent that we can afford an economically viable crop.