23 July 2021

Herbicides Reduce Hand-Weeding in Africa

Stella N. Simiyu

Consulting Director of Regulatory
Affairs and Stakeholder Relations
CropLife Africa Middle East

Hand-hoeing, a back-breaking and time-consuming task, is still the predominant way smallholder farmers (those working less than 2 hectares of land) control weeds in Africa. This group accounts for 80 percent of the continent’s farmers, 80 percent of which are women. When these farmers are shown how the responsible use of herbicides can reduce physical labor in fields, they are often eager to try it. Herbicides can increase their yields while reducing the time and cost required to manage weeds.

The majority of African farmers identify weeds as a major problem with yield losses, which can range from 25 to 100 percent. Weeds compete with crops for space, nutrients, sunlight and moisture, preventing crops from establishing stands. They are more severe in Africa than in Europe and North America because of the continent’s tropical climate and light intensity, causing weeds to grow at a faster rate. Both broadleaf weeds and grasses are problematic.

Certain weeds in Africa are also toxic and can seriously harm humans and livestock. To name a few, thorn apple or jimsonweed causes hallucinations in cattle. Worse, “famine weed” spreads rapidly and can be devastatingly destructive. It wipes out crop harvests, poisons livestock, makes food inedible and causes a variety of human health problems.

Hand-weeding is labor-intensive and back-breaking with farmers hunching over for long hours. Long-term effects can include back injuries, sprains and even physical deformities. Women bear the brunt of these health issues as weeding is frequently done by them.

Challenges with Hand-Weeding

Hand-weeding is labor-intensive and back-breaking with farmers hunching over for long hours. Long-term effects can include back injuries, sprains and even physical deformities. Women bear the brunt of these health issues as weeding is frequently done by them. Meanwhile, time-consuming hand-weeding may also prevent smallholder farmers from caring for children and/or force young people to help with farm operations instead of going to school.

In spite of the physical effort of hand-weeding, it has limited effect because weeds grow back and must be pulled again and again until crop canopies form. Using a short-handle hoe is not better as it chops both weeds and plant roots, reducing yields. These hand-weeding methods account for 50-70 percent of production labor. Farmers cannot expand their operations with such inefficiency. Let’s do the math: 500 million smallholder farms in Africa + 200 hours/hectare = 100 billion hours. Yet yield loss is still 20 to 100 percent due to untimely and ineffective weed control so a lot of time and energy are wasted.

Timeliness is essential with hand-weeding. Weeds must be cleared from a field prior to planting a crop and during the growing season. Other farm activities often postpone hand-weeding and/or labor constraints force farmers to plant crops after weeds have begun to germinate.

Late hand-weeding results in crop losses, especially if this is done after the critical period of weed competition. For example, a one-week delay before planting a maize crop may reduce yields by one-third and a two-week delay in weeding mid-season may reduce maize yields by one-quarter. When fields are easily smothered by weeds, they are typically abandoned.

Benefits of IPM and Herbicides

Integrated Pest Management (IPM), which solves pest problems, while minimizing risks to people and the environment, is an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, use of resistant varieties and pesticides when needed. Using herbicides to control weeds is often more cost-effective than hand-weeding and it can ensure weed control during the critical time before the crop canopy is established. It also omits the risk of the physical problems associated with hand-weeding and can increase farm income and time for smallholder farmers to do other things.

Research with herbicide use in Africa shows yield increases of up to 55 percent in maize and 75 percent in cotton alone.1 Plus there is a significant time savings. With a knapsack sprayer, it takes one person two hours per hectare to apply herbicide versus 3-5 people hand-weeding for five days (60 hours) per hectare! Moreover, a maize study in Kenya showed that chemical weeding was one-third the cost of two rounds of hand-weeding. Yet only 5 percent of smallholder farmers in sub-Saharan Africa use herbicides.1 This is largely due to lack of awareness and training on the benefits of herbicide technology.

How Governments can Help

Lack of knowledge is the most limiting factor to smallholder farmers adopting IPM practices, including the use of herbicides. National governments should consider encouraging the responsible use of herbicides as a key component of IPM systems and an alternative to hand-weeding. In addition, they should support agricultural extension training.

More experts are needed to train these farmers. Governments can improve this situation by supporting farmer training and attracting agronomic experts to help smallholder farmers get the advice and expertise they need.

Using herbicides to control weeds is often more cost-effective than hand-weeding and it can ensure weed control during the critical time before the crop canopy is established. It also omits the risk of the physical problems associated with hand-weeding and can increase farm income and time for smallholder farmers to do other things.

Responsible Use of Herbicides

Training on the responsible use of herbicides goes hand in hand with their adoption. CropLife Zambia and the U.S. Agency for International Development piloted a Spray Service Provider (SSP) program in Zambia in 2008, which is still running today due to its success. Following a set of strict criteria such as literacy, SSPs are selected in villages and undergo extensive training on the responsible use of pesticides. In turn, they are hired by farmers – typically women – to spray crops. For some farmers, spraying is urgently needed to overcome weed problems.

Herbicides introduced through this program have been very beneficial and more affordable than hand-weeding with farmers only needing to hire one SSP instead of 6-10 laborers. According to CARE Zambia, which monitors results, herbicide use on maize leads to yields of up to 4.5 metric tons per hectare versus 1.5-2 tons from hand-weeded fields.[2] SSPs report that it only takes them one hour per hectare to apply herbicides, so in one season, an SSP can take care of 78 hectares. With hand hoes, this same amount of land would require 468 people to weed for a whole month! As a result, the use of herbicides by smallholder farmers in Zambia has increased more than 2,000 percent in the last 12 years. Today, Zambia has about 1,300 active SSPs.


Given the success of this program, SSPs were trained in additional African countries, including Cameroon, Cote d’Ivoire, Egypt, Ethiopia, Ghana, Kenya, Madagascar, Malawi, Mali, Nigeria, Senegal, Tanzania and Uganda. Programs are either one off or run for multiple years, depending on donors and partners. All have dramatically reduced hand-weeding. There are no downsides: farmers make more food, profit and time for their families and education. Today, there are approximately 13,500 SSPs in Africa. Each help an average of 10 farms, accounting for 140,000 farmers a year. While impressive, there are about 500 million smallholder farms in Africa!

To reach millions more, CropLife Africa and Middle East launched an intensive stewardship digital outreach program, which aims to reach 1 million farmers by the end of 2021. With the COVID-19 pandemic being a major obstacle to working with farmers in the field, CropLife Africa Middle East came up with SMS messaging to train them instead. Most countries declared agriculture an essential service during the pandemic so there was a need to continue farmer outreach. So far, the program has been implemented in seven countries within the Africa Middle East region, influencing over 500,000 farmers. They have received messages on the responsible use of pesticides, including personal protective equipment, environmental protection, use of genuine products and IPM. Program monitoring revealed that more than 80 percent of the farmers reached reported a change in behavior, especially regarding the proper use of pesticides. The respondents also used the opportunity to interact with their CropLife national association.

Metaphorically, how do you eat an elephant? One bite at a time.

Stella Simiyu Wafukho is director of regulatory affairs & stakeholder relations at CropLife Africa and Middle East in Nairobi, Kenya.

 

[1] https://croplife.org/case-study/herbicide-use-in-africa-would-lead-to-large-increases-in-crop-yields/
[2] https://croplife.org/case-study/spray-service-provider-project-improves-weed-control-in-africa/

 

 

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