Mucuna bean fertilizes degraded soils

A unique bean variety is helping fertilize degraded soils due to its nitrogen fixing traits with a crop of mucuna bean capable of fixing 150kgs of nitrogen per hectare.

This coming at a time when Kenyan soils have been voted the worst in Africa in soil fertility, due to exploitation and over use of conventional fertilizers.

Mucuna also produces up to 35 tonnes of organic matter per hectare. By cutting the so-called 'cover crop' or 'green manure', and allowing the leaf material to compost naturally in the fields, soils are being recreated.

Organic farmers in Njoro area of Nakuru have relied on the crop to fertilize their soils by intercropping it with staple crops like maize. Farmers in the area have reported a doubling of maize yields by just having mucuna bean in their farms even as their counterparts struggle with application of conventional fertilizers.
The bean is also proving effective in smothering weeds, which are otherwise difficult to control.

We learnt about the use of the bean from our forefathers who never used any commercial fertilizers yet low yields and weeds were alien to them. To those who have crossed over to our side, the results have been instant and commendable,” said Kariuki Mworia one of the farmers who has never used conventional fertilizers since he started farming.

The ability of mucuna to increase yields compared to conventional fertilizer is evident in the health of maize crops between different farmers in Njoro. 

The bean that has also been hailed for its ability to hold the soil together therefore preventing soil erosion, has becoming the determinant of who gets higher yields in Njoro. “We are still apprehensive on trying the crop because we are not yet convinced and we hear it is poisonous to livestock,” said Mercy Waithera another farmer.

The downside of the bean however is that it is not ideal for human and animal consumption. However, breeding efforts are underway to try and further improve digestibility of mucuna.