Agroforestry – the incorporation of trees into farming systems – has enormous potential to mitigate the effects of drought, prevent desertification and restore degraded soils. Agroforestry can also help to boost food production (for humans as well as animals) and provide alternative sources of nutrition or income when crop yields are low.
With climate change expected to lead to unpredictable seasons in the future, placing even greater pressure on agricultural systems, food production and food prices, agroforestry is a viable option to help buffer farmers against the impacts.
Agroforestry mitigates the effects of drought and prevents desertification
Agroforestry systems increase soil organic matter and available nutrients, improving the fertility of soils and increasing productivity of the land. Trees also provide erosion control, improve water infiltration, provide land cover and shade and act as windbreaks.
In Senegal, planting strips of Casuarina spp. in the Niayes coastal stretch north of Dakar has stopped the movement of sand dunes and provided shelter from the sea winds that made any type of agriculture impossible. Market gardening is now thriving and provides a livelihood to an increasing number of settlers.
Agroforestry is cited in the United Nations Convention to Combat Desertification as a potential win-win land use system in providing key rehabilitation and other ecosystem services while also generating production and income for land users.
Agroforestry restores degraded soils boosts food production
Better soils mean better harvests. Better harvests of staple foods mean that families are less likely to go hungry.
Fertilizer trees which capture nitrogen from the atmosphere and deposit it in the soil provide a low cost way for farmers to improve soil fertility and boosts crop yields. In Malawi, Zambia, Kenya, Tanzania, Niger, Burkina Faso and other countries in sub-Saharan Africa, fertilizer trees are doubling and tripling average maize yields.
The lack of fertilizer is linked to food shortages that affect up to 90 percent of the 13 million families in southern and eastern Africa that produce maize for subsistence. Fertilizer trees provide an alternative to chemical fertilizers in countries with high fertilizer costs and inadequate transportation systems.
Across the Sahel region of Africa, yields of grains, ground nut and cotton have improved when grown under or near the fertilizer tree Faidherbia. Research in Zambia shows 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 Niger, farmers have been regenerating up to 160 Faidherbia trees per hectare on their millet and sorghum fields, and as a result their crop production and fodder supplies have been significantly enhanced.
Agroforestry provides alternative sources of food
Native trees have always been an important fall-back for the rural poor when food is scarce. In Malawi, Mozambique and Zambia, up to 80 percent of rural households go hungry for three months of the year because they cannot grow enough from their poor soils, and up to half rely on indigenous fruits to get them through. By including trees in their farms, farmers can break the cycle of hunger and provide their families with balanced nutrition.
In West and Central Africa, tree domestication by local farmers is having a remarkable impact on the health and welfare of rural communities. For many poor farmers in the drought-plagued countries Cameroon, the Democratic Republic of Congo and Nigeria, these new farming activities have boosted incomes and provided food security, especially during the ‘hungry season’.
Agroforestry provides fodder for livestock
The use of fodder trees as an alternative feed for livestock in agropastoral systems can reduce grazing pressure and the risk of grazing damage. In East Africa, an estimated 200,000 smallholder dairy farmers are using fodder trees as a source of high quality nutritious feed to boost milk yields.
In pastoral areas of sub-Saharan Africa, three-quarters of the 10,000 tree and woody species are used as fodder, supplying up to 50 percent of livestock feed, particularly during the dry season when grass and crop leftovers are scarce.
In Tanzania, a century ago, the Shinyanga area was covered with woodlands used by agropastoralists to feed their livestock. By the mid-1980s clearance of the woodlands to control tsetse fly and increasing population pressure had reduced the woodlands to just 600 hectares. In 1984, then President Julius Nyerere described it as the “desert of Tanzania”. As a result of a comprehensive soil conservation and agroforestry project, there are now 500 000 hectares of woodlots throughout Shinyanga which supply feed for animals in the dry season and smallholder farmers have seen their profits rise by as much as USD 500 per year.
Agroforestry diversifies risk and provide alternative sources of income
Farmers use trees to diversify risks as they provide alternative streams of income and increase food security. By integrating trees, farmers can decrease their dependency on a single staple crop or sufficient grass for their livestock. The diversity of plants used in agroforestry systems can provide multiple harvests at different times of the year.
In 2005, Niger faced one of the worst droughts in its history. Much of the country’s population experienced food scarcity. Those farmers who practiced Farmer Managed Natural Regeneration (FMNR) techniques, introduced in the 1980’s were able to sell the trees they had grown for timber in exchange for cereals and they depended on drought-resistant fruits and leaves to supplement their diets.
What is needed?
The value of trees outside forests (as well as in the forest) needs to be recognized by all involved in agricultural production, planning and policy development.
Policies which influence tree planting, retention and management, and those which relate to land tenure rights, need to support agroforestry.
Greater investment is needed to support smallholder farmers in adopting agroforestry practices – such as provision of tree planting material, information and training, access to credit – so that they can improve incomes and ensure food security while at the same time providing environmental benefits.
More research into appropriate agroforestry species, systems and technologies for dryland areas.
Greater support for initiatives such as the Great Green Wall which aims to re-vegetate land in Africa from Senegal in the west to Djibouti in the east. This may be a once in a lifetime opportunity to see trees bring multiple benefits while improving the productivity of the drylands on a massive scale
With the right incentives, such as improved markets for tree products or rewards for carbon sequestration and other services provided by trees, tree cover on agricultural land could be significantly increased.