Effective weed control crucial for agriculture in Africa

Weeds pose a major threat to food production in Africa, and farmers spend an estimated 50% to 70% of their time in the fields manually controlling weeds – a task that also places a significant burden on women.

By Nico van Burick, senior journalist at African Farming and Landbouweekblad

A recent study found that an urgent shift towards improved agricultural production on the continent is required to ensure food security, sustain livelihoods and protect the environment. Effective weed management is one of the most important components of successful conservation agriculture.

South Africa’s Bureau for Food and Agricultural Policy (BFAP) conducted the study in collaboration with the Tegemeo Institute for Agricultural Policy and Development in Kenya. The research focused on the use of herbicides and the role of glyphosate in Kenya.

BFAP states that Kenya’s agriculture – a cornerstone of the country’s economy – has reached a critical crossroads and that an urgent shift towards sustainable agricultural production is needed.

Africa’s growth in agricultural output has traditionally depended on expanding the area under cultivation rather than increasing yields, BFAP notes. This model is not sustainable for a population expected to double by 2050.

The investigation was based on market data and farm-level information relating to the production of key staple crops such as maize, wheat and rice. The study found that the use of herbicides leads to significant savings in production costs, particularly through reduced labour requirements.

The same area that a worker can spray with herbicide in one hour would take six people two days to clear manually.

Glyphosate’s Critical Role in Staple Food Production

The study further found that glyphosate is the active ingredient in 45% of commercial herbicides and is regarded as indispensable for staple food production. All wheat producers surveyed use herbicides and indicated that it would be extremely difficult to produce wheat without glyphosate. Without it, many would likely cease wheat production.

In the case of maize, only 16% of the area under cultivation is treated with herbicides. However, glyphosate remains the most commonly used active ingredient, particularly for pre-plant weed control.

The researchers noted that the primary challenge lies in the correct use of herbicides, not merely in market access. In Kenya, farmers’ main sources of information are traders and representatives of agricultural companies, with a shortage of independent and scientifically based advisory support.

The study concludes that herbicides – and especially glyphosate – are of considerable economic importance to the country, but that the gap in independent scientific advice and training must be addressed.

South African Perspective on Weed Control

Corné Louw, head of applied economics and member services at Grain South Africa, emphasised the importance of effective weed control, including under South African conditions where weeds compete with crops for sunlight and soil moisture.

“If weeds are not properly controlled, the impact is severely detrimental, particularly in grain production.”

“Roughly speaking, glyphosate accounts for about 60% to 65% of the local herbicide market. Many of our crops are Roundup Ready, where glyphosate effectively controls weeds without damaging the crop. Years of research have also shown that it is one of the safest, if not the safest, herbicides.”

He added that glyphosate is crucial in conservation tillage systems, particularly in low-rainfall regions such as South Africa.

“It is an input that we genuinely need.”

Expert Assessment: Safety and Scientific Evidence

Dr Gerhard Verdoorn, toxicologist and director of the Griffon Poison Information Centre, maintains after many years of research that glyphosate does not pose a risk to humans, animals or the environment when used according to label instructions.

He reiterates that all substances can be toxic.

“It is the dose that makes the difference between a poison and a useful substance.”

According to Verdoorn, reliable scientific studies have repeatedly supported the safety of glyphosate when properly applied. However, he notes that some studies test glyphosate at extremely high doses.

“This is not scientifically sound. You cannot conduct a study where an organism is exposed to a toxin at thousand times the recommended dose.”

“The principle I adhere to is that if a study is conducted at the correct dosage, with appropriate protective clothing and on the correct crops, the risk is minimal – full stop.”