Weeds are defined as any unwanted plant in the field that compete with crops for nutrients, water, space and sunlight. Weeds tend to outgrow and choke crops in the farm hence affect the productivity of the crops. Volunteer crops are also termed as weeds. Volunteer crops are defined as crops that grow on their own without being planted by the farmer. They too are considered as weeds as they compete with the main plant and can greatly affect productivity.

To effectively manage weeds farmers, need to grasp simple weed biology and science. Understanding the life cycle of weeds equips farmers with the knowledge to effectively control them in their farm. Why do we need to control weeds? Weeds are damaging with the following undesirable effects;

1.Competition for resources with the desired plants. They compete for water, direct sunlight, soil nutrients, and space.

2.They act as hosts for plant pathogens which cause crop diseases e.g. rust.

3.Provision of food or shelter for crop pests e.g. hosting aphids.

4.Cause irritation to the skin of farmers and farm workers through thorns, prickles like stinging nettle (Thabai) or chemical irritation via natural poisons e.g. Datura.

5.Bring about damage to farm equipment, farm structures like blocking waterways like streams.

Weeds are very adaptable and can reproduce quickly, disperse widely, live in a variety of habitats, colonize strange places, succeed in disturbed ecosystems and resist eradication. A successful weed control regime should:

1.Factor the weed growth cycle

Under this there are perennial and annuals. Annuals have a shorter growth cycle as compared to perennials. Perennials like most grasses propagate through rhizomes, roots and stolons. Annuals mostly propagate by seeds and life cycle will normally grow and die within a season.

2.Select environmentally safe approaches

Farming has been described as one of the main sources of pollutants so always consider the effect your weed control method has on the environment.

3. Always select the most cost effective control method

Pick the pocket friendly control method.

There are different ways to control weeds.

  1. Preventative Weed Control

This method involves practices that prevent establishment of weeds in cultivated crops. Such practices include cover crops, mulches, use of weed free seeds and equipment.

  1. Cultural Weed Control

Crop rotation, maintenance of soil fertility, intercropping and early planting are examples of cultural weed control methods.

  1. Mechanical Weed Control

This involves techniques that mechanically remove weeds from the farm like tillage, mowing/cutting.

  1. Biological Weed Control

This involves the use of natural enemies to control weeds. Example of such is the use of goats to control bushes in a farm.

  1. Chemical Weed Control

This involves the use of chemicals to kill weeds. When using these methods farmers are advised to follow application and safety procedures. Clear understanding of the active ingredients helps in selection of chemicals to use for different weeds e.g. broad leafed weeds have a specific chemical and so do grasses and similar weeds. There are also broad spectrum chemicals.


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Farming;Farmers;Weeds