BBC News – The nitrogen-fixing roots of certain trees provide valuable nutrients to resource-poor arable land Planting trees that improve soil quality can help boost crop yields for African farmers, an assessment shows.
Fertiliser tree systems (FTS) also help boost food security and play a role in “climate proofing” the region’s arable land, the paper adds.
Researchers from the World Agroforestry Centre say poor soil fertility is one of the main obstacles to improving food production in Africa.
Some of the studies have shown that in TFS (Tree Fertiliser Systems) across Africa as a whole, yields are doubling or more in two-thirds of cases.
The Faidherbia tree – pending some further research on its impact on the water table – may now provide a natural and widespread fertilizer fix. According to the Agroforestry Centre, farmers in Malawi testify the tree is like a “fertilizer factory in the field”, as it takes nitrogen from the air, fixes it in the leaves and subsequently incorporates it into the soil. The Agroforestry Centre’s research showed that in Malawi maize yields increased by 280 per cent in the zone under the tree canopy compared with the zone outside the tree canopy. In Zambia, unfertilized maize yields in the vicinity of Faidherbia trees averaged 4.1 tonnes per hectare, compared to 1.3 tonnes nearby but beyond the tree canopy.
In response to the declining soil fertility in southern Africa and the negative effects that this leads to, such as food insecurity besides other developmental challenges, fertilizer tree systems (FTS) were developed as technological innovation to help smallholder farmers to build soil organic matter and fertility in a sustainable manner. In this paper, we trace the historical background and highlight the developmental phases and outcomes of the technology. The synthesis shows that FTS are inexpensive technologies that significantly raise crop yields, reduce food insecurity and enhance environmental services and resilience of agro-ecologies. Many of the achievements recorded with FTS can be traced to some key factors: the availability of a suite of technological options that are appropriate in a range of different household and ecological circumstances, partnership between multiple institutions and disciplines in the development of the technology, active encouragement of farmer innovations in the adaptation process and proactive engagement of several consortia of partner institutions to scale up the technology in farming communities. It is recommended that smallholder farmers would benefit if rural development planners emphasize the merits of different fertility replenishment approaches and taking advantage of the synergy between FTS and mineral fertilizers rather than focusing on `organic vs. inorganic’ debates.