1. Mechanical weeder

​A mechanical weeder is a hand-operated device that allows quick and efficient weeding of line-sown or line-transplanted rice. It can cut, uproot and bury weeds. It should be followed by hand weeding of the remaining weeds very close to the rice plants. Several types of lowland and upland specific weeders are available. 


Where piloted

Participatory weeder selection was conducted in Benin, Côte d'Ivoire, Ghana, Madagascar, Nigeria, Sierra Leone, and Tanzania to identify the best suitable weeders.


Success factors

A range of mechanical weeders is required to suit farmers’ preferences and the diversity of soil and water conditions. Mechanical weeders require levelled field and uniform crop establishment (line-sown or line-transplanted rice fields). Local blacksmiths should be trained, so that they can produce the weeders and sell to farmers.  


Benefits and impact on livelihoods at the pilot sites

Mechanical weeders present a viable alternative for reducing the labor required for weeding. Tests in Tanzania show that the ‘straight-spike floating weeder’ reduced weeding time by 32% to 49% and the ‘twisted-spike floating weeder’ reduced weeding time by 32% to 56%, compared to hand weeding with similar weed control efficacy. As hand weeding in rice is mainly done by women and children, the introduction of mechanical weeders will likely play a major role in improving women’s and children’s lives in rural areas in Africa. The estimated time saving of 32% to 56% will have a positive impact on the whole household.


In the SARD-SC project, it was found that women rice farmers prefer the mechanical ‘ring hoe weeder’ and the ‘straight-spike’ weeder because of their ease of operation and high efficiency. As part of the project, local artisans in Glazoué in Benin and Lafia in Nigeria, were trained in the fabrication of the ring hoe weeders in collaboration with national agricultural research systems. The mechanical weeders were shared with farmers in Benin, Côte d'Ivoire, Ghana, Madagascar, Nigeria, Sierra Leone, and Tanzania. About 80% of male and female farmers who used the ‘ring hoe’ indicated that weeding time was reduced by at least 31%. About 35% of farmers also used it for other crops such as vegetables, maize, sorghum, cassava and millet.



Mechanical weeders are suitable for all rice-growing environments.



2. Motorized weeder

Motorized weeders can reduce labor inputs for weeding and are engine-operated machines that allow quick and efficient weeding of line-sown or line-transplanted rice in irrigated lowlands. Different models of motorized lowland weeders are available.


A prototype hybrid motorized weeder for rainfed lowland and irrigated conditions was developed by AfricaRice in partnership with a private sector artisan in Tanzania. It combines the features of double-row Indian- and Japanese-type motorized weeders for effective weed control.


Where piloted

The motorized weeders were piloted in Tanzania and Madagascar.


Success factors

Locally fabricated prototypes and/or technical drawings should be available for local engineers to make it. Two-stroke engines should be also available.


Benefits and impact on livelihoods at the pilot sites

Initial tests of the motorized weeder with about 330 farmers were positive, with 85% of them considering it as a cost-effective and time-saving option. It was preferred mostly for its effectiveness for weed control and stability. About 70% of the farmers indicated that they would like to buy and own the weeder individually while 30% preferred to acquire it as a group, because they could not afford to buy it on their own. The time saved with the motorized weeder compared to hand weeding is estimated to be around 90%.



The motorized weeder can be applied in irrigated and rainfed lowland rice in Africa.

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