Fertilizer trees are used in agroforestry to improve the condition of

soil Soil, also commonly referred to as earth or dirt Dirt is an unclean matter, especially when in contact with a person's clothes, skin, or possessions. In such cases, they are said to become dirty. Common types of dirt include: * Debri ...

s used for

farming Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled peopl ...

. As woody legumes, they capture nitrogen from the air and put it in the soil through their roots and falling leaves. They can also bring nutrients from deep in the soil up to the surface for crops with roots that cannot reach that depth. Fertilizer trees are further useful for preventing fertilizer erosion,

soil degradation Soil retrogression and degradation are two regressive evolution processes associated with the loss of equilibrium of a stable soil. Retrogression is primarily due to soil erosion and corresponds to a phenomenon where succession reverts the land to ...

and related desertification, and improving water usage for crops. ''

Sesbania ''Sesbania'' is a genus of flowering plants in the pea family, Fabaceae, and the only genus found in tribe Sesbanieae. Riverhemp is a common name for plants in this genus. Notable species include the rattlebox ('' Sesbania punicea''), spiny se ...

'', ''

Gliricidia ''Gliricidia'' is a genus of flowering plants in the legume family, Fabaceae and tribe Robinieae. Its native range is Mexico to Peru, but ''Gliricidia sepium'' has been widely introduced to other tropical zones. The species ''G. sepium'' is a ...

'', ''

Tephrosia ''Tephrosia'' is a genus of flowering plants in the pea family, Fabaceae. It is widespread in both the Eastern and Western Hemisphere, where it is found in tropical and warm-temperate regions. The generic name is derived from the Greek word τ ...

'', and ''

Faidherbia albida ''Faidherbia'' is a genus of leguminous plants containing one species, ''Faidherbia albida'', which was formerly widely included in the genus ''Acacia'' as ''Acacia albida''. The species is native to Africa and the Middle East and has also been ...

'' are known as fertilizer trees. Tree lucerne or tagasaste ('' Cytisus proliferus'') is able to fix more than 587 kg. of nitrogen per hectare per year. It can increase maize (corn) yields from 1 ton per hectare per year to more than 10 tons per ha/year in areas with more than 850 mm. of rain per year or a perched water table. Tree lucerne is also used to create and maintain

terra preta ''Terra preta'' (, locally , literally "black soil" in Portuguese) is a type of very dark, fertile anthropogenic soil ( anthrosol) found in the Amazon Basin. It is also known as "Amazonian dark earth" or "Indian black earth". In Portuguese its f ...

Use in Africa

The use of ''

'' in

Malawi Malawi (; or aláwi Tumbuka: ''Malaŵi''), officially the Republic of Malawi, is a landlocked country in Southeastern Africa that was formerly known as Nyasaland. It is bordered by Zambia to the west, Tanzania to the north and northeas ...

and

Zambia Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most central point. Its neighbours are t ...

has resulted in a doubling or even tripling of maize yields. As part of evergreen agriculture, use of fertilizer trees is proposed as a means to improve food security. Niger has more than 4.8 million hectares of predominantly Faidherbia agroforests, while Zambia has 300,000 hectares. In Zambia and Malawi, farmers plant the trees in a checkerboard pattern every 30 feet. Fertilizer trees are used to prevent the expansion of desert, and to keep agriculture viable in arid lands in many African countries.

References

{{Authority control Agroecology Sustainable forest management

Use in Africa

See also

References