Preventive Methods of Weed Control Guide
Preventive weed control refers to those measures necessary to prevent the introduction of new weed species into a given geographical area as well as multiplication and spread of existing weed species.
Preventive weed control includes all sanitation measures that should be routinely used in the farm, including the vigilance that keeps a farmer alert to the presence of a strange plant on his farm land.
It’s generally accepted wisdom that it is easier to prevent the spread of a weed to a new site than to get rid of it after it is well established.
1. Fallowing
This is an effective method of suppressing annual grasses and troublesome perennial weeds such as speargrass.
Although fallowing has been used for controlling weeds, proper management of fallows can be used to prevent weeds from going to seed and reduce weed population in a given ecology.
An example of preventive weed management by bush fallowing is the live mulch cropping system. In this system the living cover of legumes such as Centrosema pubescens and Mucuna pruriens provide complete cover, smother weeds, prevent erosion and return organic matter to the soil.
2. Preventing weeds from setting seeds
Annual weeds and simple perennials produce large quantities of seeds that end up in the seed bank already in the soil.
Late germinating weeds in the field crops are the main sources of weed seeds in newly harvested field because these weeds usually complete their life cycle after crop harvest.
Methods of preventing weeds from going to seed
Post- harvest weed control will be necessary to prevent these weeds from going to seed (producing seeds).
Enlightening the farmers on the adverse effects that seeds produced by these volunteer weeds will have on their subsequent use of the land.
Repeated mowing and hand-slashing can be used to deplete the food reserve in the storage organs of perennial weeds there by reducing their competitiveness.
Preventing the spread of weeds and their propagules by the use of clean seeds for planting.
Weed spread through the use of contaminated crop seeds can be prevented by keeping crop plants in the field weed-free.
By thoroughly cleaning the seeds intended for planting in the following cropping season.
Planting weed-free crop seeds is one way of avoiding the introduction of new weed seeds to the newly cleared crop land.
Cultivating tools play a role in spreading weed seeds and vegetative perennating organs. Routine sanitary measure involving careful cleaning of farm machinery immediately after use is an important preventive measure for weed control.
Seeds of many weeds are spread by animals. Care should be taken by the farmer to organise carefully the transfer of farm animals between fields.
Preventive weed control can also be achieved by screening irrigation canals to prevent weed seeds from being transported from infested fields to clean areas.
Read Also : Animal Teat Management and How to Clean Teats
Well-decomposed manure is unlikely to contain viable weed seeds but poorly prepared manure which is a potential source of weed seeds, therefore, should be avoided.
Strict enforcement of quarantine laws is necessary to prevent the accidental introduction of noxious weeds through seeds and propagules.
Integrated Weed Management System
Integrated weed management (IWM) is neither a method nor a system of weed control, but a philosophy whose goals is to use all available knowledge in weed science to manage weeds so that they do not cause economic loss to humans and subsequently minimizing hazards to the environment.
Reasons that made IWM desirable
Inability of any one method of weed control to completely solve the weed problem of a given crop at all times and without adverse effect.
The ability of weeds to develop resistance to a herbicide that is frequently used.
In summary, by now you must have learnt the different methods of weed control including cultural, biological, chemical or integrated weed control programme. The emphasis has been on “Prevention is better than cure” so your knowledge of weed science should help you to manage weeds so that they do not cause economic loss to the farmer and subsequently minimize hazards to the environment.
Understanding the different types of herbicides, their mode of action, time of application and types of plants they commonly kill is essential for an effective weed control programme.
The integration of cultural, biological and chemical methods of weed control in other words integrated weed control is the most sustainable and effective method of weed control programme.
Read Also : 10 Health Benefits of Scent Leaves (Ocimum gratissimum)
