As woody legumes, they capture nitrogen from the air and put it in the soil through their roots and falling leaves.
[1] They can also bring nutrients from deep in the soil up to the surface for crops with roots that cannot reach that depth.
The use of Faidherbia albida in Malawi and Zambia has resulted in a doubling or even tripling of maize yields.
[3] As part of evergreen agriculture, use of fertilizer trees is proposed as a means to improve food security.
[4] Fertilizer trees are used to prevent the expansion of desert, and to keep agriculture viable in arid lands in many African countries.