Weed management: How to get rid of weeds

Farmworkers weed out a 1600 acres sugarcane farm in Chemelil, Kisumu County in July 2019. [File, Standard]

Weeds are unwanted and undesirable plants that grow in areas they need to be. They compete with a farmer’s crops for water, nutrients, sunlight, space and moisture.

They also weaken the health of the crops thus resulting in low yields and if not managed in time they harbour pests and diseases.

They are mostly spread in an area naturally through wind, water and animals. Varying human activities can also lead to weed dispersal.

Why do they need to be managed in time?

Weeds will increase the cost of agricultural production. A farmer will have to incur more cost by buying extra chemical since they have a vigorous growth habit and high seed production.

Reduce the value and quality of produce. As mentioned, they compete with the crops for nutrients and other requirements for healthy crops hence producing low yields, weeds reduce the crop production value, quantity and quality.

Reduce land value. With the weeds competing with the crops for nutrients, they will use up the nutrients present in the soil hence reducing its fertility. Their high seed production output and dormancy can reduce the land value if the weed becomes hard to manage.

Reduce crop yields. The crops and weed will be competing for nutrients resulting in unhealthy plants and later low yields. They attract pests and diseases if not acted upon in time they will lead to low yields caused by pest and diseases infestation.

Weeds are poisonous and can cause death or stunted growth in plants. Their strong competitive abilities for nutrients and vigorous growth rate can lead to stunted growth in crops. Some cause human health problems such as asthma and respiratory-related diseases in children and skin irritation.

How can they be managed?

Different methods can be used to minimise and reduce their spread whilst reducing production costs and environmental pollution. These methods include preventive, cultural practices, mechanical, and chemical methods.

Preventive

This the process of monitoring farming activities to avoid introducing farming materials contaminated with weed seeds such as manure, equipment, crops and seeds. This method requires farmers to ensure they buy certified seeds or from a trusted source, farm equipment should be washed before and after use and avoid sharing farm equipment.

Farmers should buy manure from trusted sources. Ensure your manure is weed-free by destroying or burning weeds rather than feeding it to the livestock.

Cultural practices

These are practices that help crops to be more competitive against the weeds. They include mulching, crop rotation, intercropping, use of cover crops and crop variety selection. They discourage weed growth and build up in the soil.

Mechanical

It involves the use of jembes, machetes, slashers and pangas to disrupt their growth and survival. A farmer can use them to slash, cultivate and remove weeds from the farm. In some cases, hand pulling is the best mechanical method due to minimum crop disturbance. If weed present in the farm is less, hand pulling can be the most economical control method.

Chemical

It is the application of herbicides that kill or inhibit weed growth. A farmer should use the chemicals appropriately to avoid environmental pollution. While applying herbicides, check on the proper application timing guidelines, apply recommended rates, application methods and observe precautions on the label.

Remember to ensure you select the suitable herbicides to use, check herbicides label to determine application rate and rinse spray equipment immediately after use

However, it is important to manage weeds immediately before they start producing seeds. Incorporating two or more methods is the most effective way to eradicate weeds on your farm.