Agroforestry, a sustainable agricultural system
Most dryland smallholder farmers rely on low productivity monocultures of low value staple crops. These cropping systems are unsustainable, causing land degradation, food insecurity and poverty.
Agroforestry is an integrated crop and tree farming system which can improve overall agricultural production per hectare, diversify production and nutrition, preserve the soil and increase incomes in marginal lands.
Trees with their deep root systems and their sun-protecting canopy are important to preserve soil and water resources in the semi-arid tropics, and could help annual crops grow better.
More than 50% of the West African Sahel land is degraded and not suitable for cultivation. In most cases the degraded land is composed of crusted lateritic soils impermeable to water. A combination of hardy rain-fed fruit trees and high value annual crops like vegetables, with water conservation techniques such as demi-lunes, zai and other sorts of planting pits, help women to improve food production and nutrition in waste lands. In general trees, a major component of the Bioreclamation of Degraded Lands, are much more resilient to droughts than annual crops.
Pigeonpea can be cultivated as a perennial plant and is used as a multipurpose species in agroforestry systems. This grain legume is thus planted in China to fight soil erosion in mountainous regions.
ICRISAT has developed a farmer generated natural regeneration approach which consists of actively managing and protecting indigenous non-planted trees. It is a low-cost and effective way to combat desertification in the Sahel, avoiding the adoption issues of large-scale tree nursery development of other replanting programmes.
Together with the International Center for Research in Agroforestry (ICRAF), we are looking at crop-tree and crop-tree-livestock synergies to sustainably improve smallholder farmers livelihoods in West Africa [see Cerlivestree project]
In India, legume trees such as glyceridia, planted on bunds help fighting against soil erosion, boosting soil fertility (through biological nitrogen fixation) and water conservation. These trees are promoted in particular under Bhoo Chetana, watershed research programmes and other natural resources management initiatives.
Agroforestry has a role to play in helping smallholder farmers adapt to climate change.
Agroforestry provides multiple resources for better nutrition and livelihoods
Trees in the different farming systems of semi-arid tropics provide plenty of essential resources to farmers.
Energy - Trees are a source of energy. Firewood - most people in rural SAT use biomass for cooking and heating - but also biofuel. Oilseeds from Jatropha curcas can be used by rural communities to produce biodiesel. This is a hardy tree capable of withstanding inhospitable environments with simple water conservation pits. A pilot plantation in Andhra Pradesh is generating substantial incomes for landless farmers from biodiesel production, while the de-oiled cake can be used as fertilizer. Jatropha cultivation is also being experimented with in Sahel using different water and soil conservation techniques.
Nutrition - Planting trees is a way for farmers to get nutritious food. The "Apple of the Sahel" or in French, "Pomme du Sahel" is particularly resistant to drought and produces tasty fruit with ten times the concentration of Vitamin C as compared with apples. It is also rich in iron, calcium and phosphorus and in essential amino acids. Another valuable tree is Moringa stenopetala whose leaves are one of the most nutritious vegetables known: they have seven times the Vitamin C in oranges, four times the Vitamin A in carrots, four times the Calcium in milk, double the protein in milk and three times the potassium in bananas.
Other benefits - In addition to food (fruit and seeds in particular) and fodder, trees can provide other essential resources and services: timber wood, live fences to stop wind and define properties ; cosmetics and medicinal use, shade etc.
Other interesting trees for the Sahel include tamarind (provides fruit) ; Sclerocarya birrea sub-species Caffra a drought-tolerant tree, its fruits are used to produce beverages and the oily kernels are used as tasty nuts or in cosmetics ; Acacia senegal provides gum arabic. [source : BDL flyer]
Way forward for scaling up agroforestry innovations
To increase the adoption of improved agroforestry systems among resource-poor farmers, in particular women farmers, capacity-building of farmers, extension services and policy-makers as well as strategic partnerships are necessary. We could partner for instance with gender-sensitive NGOs or community organisations to expand the BDL, rotational woodlot technology [Peter Allan Oduol et al, p228 ] or other agroforestry systems on common "waste" lands to unlock the issue of land access for women.
One research issue is to develop efficient and sustainable tree seed and seedling delivery systems. Financing of tree dissemination is critical as they will only start producing some years after planting while demanding regular farm investments (labour, fertilizer etc) for correct survival rate and growth. Food for Work, long-term credit schemes, appropriate incentive schemes have to be tested. Carbon finance can help monetize certain ecological services and support activities to scale up agroforestry.
Training courses on tree propagation, nursery techniques and tree seed collections and management have to be developed for farmers, but also research and development partners with focus on multipurpose tree species in the Sahel.
Improving the marketing of agroforestry products will increase the socio-economic benefits of agroforestry for smallholder families.