WEED MANAGEMENT METHODS AND

INTEGRATED WEED MANAGEMENT

• The sustainable use of all available methods to reduce weed pressure without reducing farm income and damaging the environment.

• Integration of effective and environmentally safe weed control methods.

Integrated Weed Management (IWM)

• The main emphasis is on herbicides. • There have been many concerns with

regard to environmental, economic and social impacts

of agriculture and its sustainability.• The reduction of pesticide use has become

an important objective in both agricultural policy making

and research.

Conventional Weed Management

With the IWM approach each practice (e.g., herbicides) supplement other practices rather

than serve as the sole tactic for weed control serve

as the sole tactic for weed control.• The main emphasis is on:• Prevention• Enhancing crop competition• Reducing weed density

IWM

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Weed management is an important component of plant protection improving the production potential of crops.

Methods of Weed ControlFor designing any weed control programme in a given area, one must know the nature & habitat of the weeds in that area, how they react to environmental changes & how they respond to herbicides.

Principles of weed control are;

Prevention Eradication Control Management

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Preventive weed control

It is a long term planning so that the weeds could be controlled or managed more effectively and economically than is possible where these are allowed to disperse freely.Following preventive control measures are suggested for adoption wherever possible & practicable.

1. Avoid using crop that are infested with weed seeds for sowing2. Avoid feeding screenings and other material containing weed

seeds to the farm animals.3. Avoid adding weeds to the manure pits.4. Clean the farm machinery thoroughly before moving it from one

field to another. This is particularly important for seed drills5. Avoid the use of gravel sand and soil from weed-infested

Cont…

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6. Inspect nursery stock for the presence of weed seedlings, tubers, rhizomes, etc.

7. Keep irrigation channels, fence-lines, and un-cropped areas clean

8.Use vigilance. Inspect your farm frequently for any strange looking weed seedlings. Destroy such patches of a new weed by digging deep and burning the weed along with its roots. Sterilize the spot with suitable chemical

9. Quarantine regulations are available in almost all countries to deny the entry of weed seeds and other propagules into a country through airports and shipyards.

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Weed free crop seeds

Separating crop seeds from admixture of crop & weed seeds using physical differences like size, shape, colour, weight / texture & electrical properties

b. Eradication: (ideal weed control rarely achieved)

It infers that a given weed species, its seed & vegetative part has been killed or completely removed from a given area & that weed will not reappear unless reintroduced to the area.

c. ControlIn control methods, the weeds are seldom killed but their growth is severely restricted, the crop makes a normal yield.

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d. Weed management

Weed control aims at only putting down the weeds present by some kind of physical or chemical means while weed management is a system approach whereby whole land use planning is done in advance to minimize the very invasion of weeds in aggressive forms and give crop plants a strongly competitive advantage over the weeds.

Weed control methods are grouped into cultural, physical, chemical and biological.

Every method of weed control has its own advantages and disadvantages.

No single method is successful under all weed situations. Many a time, a combination of these methods gives effective and economic control than a single method.

Precision Agriculture

An agricultural practice based on in-field variability. • It requires the use of new technologies such as It requires the use of new technologies, such as global positioning, sensors and information management tools to assess and understand variations. • Estimate pesticides and fertilizers needs in different locations of the farms different locations of the farms.• Maximize profits and reduce negative environmental impacts by placing herbicides and fertilizer where it needed

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An integrated weed management may be defined as the combination of two or more weed-control methods at low input levels to reduce weed competition in a given cropping system below the economical threshold level.

It has proved to be a valuable concept in a few cases, though much is still to be done to extend it to the small farmers’ level. 

Integrated Weed Management (IWM) approach aims at minimizing the residue problem in plant, soil, air and water.

An IWM involves the utilization of a combination of mechanical, chemical and cultural practices of weed management in a planned sequence, so designed as not to affect the ecosystem.

The nature and intensity of the species to be controlled, the sequence of crops that are raised in the rotation, the standard of crop husbandry, and the ready and timely availability of any method and the economics of different weed-management techniques are some of the potent considerations that determine the success for the exploitation of the IWM approach.

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Concept Uses a variety of technologies in a single weed

management with the objective to produce optimum crop yield at a minimum cost taking in to consideration ecological and socio-economic constraints under a given agro-ecosystem.

A system in which two or more methods are used to control a weed. These methods may include cultural practices, natural enemies and selective herbicides.

Advantages of IWM

It shifts the crop-weed competition in favour of crop Prevents weed shift towards perennial nature Prevents resistance in weeds to herbicides No danger of herbicide residue in soil or plant No environmental pollution Gives higher net return Suitable for high cropping intensity