DRC : Women farmers use velvet bean to improve soil fertility and boost yields

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It is 8 a.m. in the village of Kanyuka, about 4 kilometres from the city of Kananga in the Democratic Republic of Congo (DRC). Thérèse Ntumba is in her one-hectare cassava field, checking on her crops. She is pleased to see them growing strong and healthy.

Mrs. Ntumba says: “Many people said farming here wasn’t possible, but I’m proving that’s not true.”

Mrs. Ntumba grows cassava alongside velvet bean, scientifically known as Mucuna pruriens, a legume used as a cover crop to naturally enrich the soil and boost her field’s productivity. Land that was once low-yielding is now thriving thanks to this planting method.

Mrs. Ntumba explains that she learned this technique from her mother, a farmer trained at the University of Kananga. After noticing a decline in productivity over the past three years due to soil depletion, Mrs. Ntumba decided to apply a traditional technique she learned from her mother to restore fertility to her field.

Mrs. Ntumba explains that she plants velvet beans two to three months before the growing season. After the plant has grown, its stems and leaves are cut and spread across the field. The plant decomposes  to enrich the soil naturally. She explains that this cover cropping technique helps protect the soil against erosion, reduces weed growth, and enriches the soil with nitrogen. Mrs. Ntumba says: “I am proud to see my fields producing like never before.”

Mrs. Ntumba says that since adopting this technique in 2023, her harvest has increased dramatically. She can now collect up to five tonnes of cassava per season, compared with less than one tonne before she started planting velvet beans.

Athanase Kankonde is an agro-food expert and instructor at the Higher Institute of Rural Development in Kananga. He says that velvet bean is an exceptional legume for soil fertilization. It acts as a green manure that enriches the soil with nitrogen, produces high biomass, improves soil structure, limits erosion through its mulch, and suppresses weeds. Mr. Kankonde adds that velvet bean used as mulch contributes to sustainably increasing yields.

Mrs. Ntumba’s success with cover crops has impressed farmers in Kanyuka, who visit her field to learn more. Marie Lenyi, a farmer in her forties, is one of the participants in Mrs. Ntumba’s training. She confirms the effectiveness of this technique. She explains that a few years ago her field had become infertile. She approached Mrs. Ntumba to learn about the benefits of planting velvet beans. Today, Mrs. Lenyi says she harvests twice as much as before thanks to planting velvet beans in her field. She says: “I used to struggle to get good harvests. Since adopting the technique, my groundnut and maize fields yield more and the soil has become more fertile.”

Mr. Kankonde says that sharing knowledge about this technique has allowed several farmers’ fields in Kananga to be refertilized. He notes that before adopting velvet bean, nearly 60% of the village’s fields were considered low-yielding and difficult to cultivate. Today, thanks to the use of cover crops, more than 15 hectares have been restored in three years and produce regularly. The technique has particularly allowed women farmers to increase their yields and reduce the use of chemical fertilizers. He invites other farmers in the region to adopt this practice to improve soil fertility.

For Mrs. Ntumba, beyond the economic gains, the issue is also collective. She considers it a way to restore land and strengthen food security. To this end, she wants to continue sharing her know-how with other villages so that more land can regain its fertility. Mrs. Ntumba concludes: “We all need to adopt this technique because our survival depends on it.”