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Multiple useage of Australian Acacias in sub Saharan Africa

Text by:
Tony Rinaudo (Senior Country Program Coordinator, Africa, Middle East and Eastern Europe team, World Vision Australia, 1 Vision Drive, East Burwood, Victoria 3151, Australia; email: rinaudot@wva.org.au) and
Lex Thomson (SPRIG Project Team Leader, Ensis, The joint forces of CSIRO and SCION (formerly Forest Research), PO Box E4008, Kingston, Canberra, ACT, 2604, Australia; email: Lex.Thomson@ensisjv.com)


Acacia colei
var. colei bumper crop in Maradi , Niger Republic . Note some pods are ripe, others are green. If seed is not collected daily or every other day, much seed is lost through shattering.
Photo by Tony Rinaudo.


Ethiopian girl with Injera bread (made from a mixture of A. saligna and Teff flour).
Photo by Tony Rinaudo.


Acacia colei
and other Acacia species growing in bush nursery at Kourungoussou , Niger Republic.
Photo by Tony Rinaudo.

Human populations living in semi-arid regions of the developing, tropical world who are reliant on annual crops and/or pastures (for livestock) for food are particularly vulnerable to hunger and periodic famine. This is especially evident in sub-Saharan Africa. In our 2002 paper 'Potential of Australian Acacias in combating hunger in semi-arid lands', attention was drawn to the vast, untapped potential of certain Australian Acacia species as new food crops, worthy of larger scale promotion, particularly in semi-arid regions of the world.

 


Wood collected from A. colei var colei at Dandja trial site, Niger Republic . Trees planted in rows 25 meters apart protect annual crops from strong winds, provide valuable firewood when pruned in the dry season and edible seed before the onset of rains. The trees respond positively to moderate to heavy pruning, exhibiting rapid re-growth of shoots which subsequently flower vigorously and set seed. Pruning appears to extend the life span of A. colei and stimulates increased biomass and seed production.
Photo by Tony Rinaudo.


Acacia colei var . colei used as a multi purpose windbreak in Niger Republic , protecting annual crops and providing firewood, mulch and edible seed.
Photo by Tony Rinaudo.

Acacia as human food

A number of species of edible-seeded Australian acacias thrive under adverse conditions; conditions under which many annual plants barely survive. The seeds of these species are tasty, safe to consume and nutritious, being high in protein, carbohydrates and fats. Being perennial and thus having an established root system, mature acacias can take advantage of rains that would be ineffective for annual crops (e.g. out of season or poorly distributed rains). Acacia seeds are easily harvested and processed into flour using simple and existing local technologies. The flour can be incorporated into local dishes and in "non traditional" foods such as spaghetti, bread and biscuits. The seed also has great potential as livestock feed. Alternatively, the hard-coated seeds can easily be stored for many years and act as a famine reserve food.

 


Roasting A. saligna seed prior to grinding into flour for making Kollo (Kollo is normally a roasted barley snack food).
Photographed in Ethiopia by Tony Rinaudo.


Traditional porridge ('Tuwo') made from 25% A. colei flour and 75% millet flour.
Photographed in Niger Republic, 1998, by Oliver Strewe.


Making bread using a mixture of 25% A. saligna flour and 75% corn flour.
Photographed in Ethiopia by Tony Rinaudo.


Expert Ethiopian taste-testers eating bread made with 25% A. saligna flour.
Photo by Tony Rinaudo.

Acacia colei

Acacia colei is one of the introduced Australian species that is commonly used as a human food in sub-Saharan Africa . This species comprises two varieties, var. colei and var. ileocarpa, which are distinguished by their pods, curved in the former and tightly coiled in the latter. Both varieties are used but they have different characteristics that affect their utilisation. There is no distinction in taste between the two varieties, however physical differences in their seed pods have a large bearing on convenience of harvesting.

For var. ileocarpa, seeds are held firmly in their coiled pods, hence ripe pods can be left on the tree longer without seed loss. Pickers can wait for a high proportion of the pods to ripen before harvesting, spending less time on repeat harvests. Additionally, even though the pods hold seed longer, once fully dry, a light beating with a stick will separate seed from pods.

In West Africa, var. colei pods ripen unevenly, and seed begins to drop from pods within a day or so of ripening. Thus, pickers must return daily to harvest newly ripened pods.

Alternatively, pods of both varieties can be picked slightly green and laid on a mat to dry in the sun. Even so, losses from shattering are less likely with var ileocarpa, giving farmers more flexibility.

 


Acacia colei var. colei. Note curved pods and seed is not held tightly by the pod. Seed losses can be reduced by picking slightly green, before pods turn brown.
Photographed in Niger Republic, by Tony Rinaudo.


Acacia colei var. ileocarpa. Note tightly coiled pods with a fairly even ripening of seeds in pods. Even though some pods are still green, seeds remain in ripe pods long enough to delay harvesting until most pods are ripe.
Photographed in Niger Republic, by O. Strewe.

Sahelian Eco-Farm Concept

In some areas, considerable effort has gone into promoting edible seeded Australian acacias for direct human consumption, but adoption has been low. Meanwhile, Professor Dov Pasternak, working at the ICRISAT Sahel Center in Niger Republic has given a new direction and momentum by using acacia trees as the backbone of his Sahel Eco Farm (SEF) concept. The annual biomass produced by Acacia colei and A. tumida is three fold higher than the biomass produces by local trees. Their very high biomass production is the key to greatly lifting yields of millet, the staple crop in the region - through mulch on an annual basis, organic matter incorporation into the soil, including root biomass after coppicing, nitrogen fixation, and wind break effect. Pruned trees provide firewood and coppice regrowth provides an average 2kg of seeds per year with a 25% crude protein content which are used for chicken feed.

 


Block planting of A. colei var colei , Niger Republic . Acacias are used here for restoring soil fertility on exhausted plots, firewood production and seeds for food.
Photo by Tony Rinaudo.


Bean cake made with 25% A. colei flour and 75% cow pea flour (black eye bean).
Photographed in Niger Republic , 1998, by Oliver Strewe.

Acacia saligna

Acacia saligna has been planted extensively on barren hillsides in Ethiopia by government and various non government organizations. World Vision is currently exploring potential human food uses of this versatile species. So it has been mixed at a ratio of 1 part saligna to 3 parts corn flour to make bread, and 1 part saligna to 3 parts teff (Eragrostis sp.) flour to make Injera, a very popular traditional flat bread used in many parts of Ethiopia. A number of cooking demonstrations have been held and the foods were well received, but no data is available yet on possible adoption rates.

Information on A. saligna research is presented elsewhere on Worldwidewattle.

Continuing Research Efforts (Acacia torulosa)

Staff of the Niger National Research Centre (INRAN) and SIM International continue to research potential uses and roles of Australian acacias in Sahelian farming systems. In their recent paper, Domestication of Australian Acacias for the Sahelian zone of West Africa, Cunningham and Abasse summarize past and present development and domestication achievements and outline current research activities. They propose future research directions and call for a long-term collaborative approach to ensure these species are domesticated and their long recognized potential becomes a reality. Until this time, much of the research and development effort has focused on A. colei. Even so, constraints of A. colei and the impressive growth and yield characteristics of A. torulosa has resulted in INRAN and SIM focusing their present research activities on the latter.

Under climatic conditions in Maradi, direct sowing of A. colei has given generally poor results. Acacia torulosa on the other hand has larger seed and early indications are that this species is much more suitable for direct sowing. This is a great advantage as it will enable poor farmers to by pass the relatively expensive and labour intensive process of raising trees in nurseries. As with A. colei, termites eat and incorporate the phyllodes of A. torulosa into the soil, thus increasing fertility. In the Sahel region termites perform the same tasks undertaken by earth worms in temperate climates, hence they are important for incorporation of organic matter into the soil, soil aeration and water infiltration. Termites are significant in the low nutrient, low organic matter soils of Niger where few farmers can afford organic or inorganic fertilizers and yields of millet average only 250-300Kg per hectare nationally. The ability of plants to coppice is a big advantage in countries such as Niger where there is high pressure on trees for wood and farmers are very attracted to the rapid returns through sale of firewood. Acacia torulosa responds well or pruning either at ground level or at one meter. An arborescent form of A. torulosa is well suited to producing medium sized poles and this is eagerly sought after for local building tasks (huts, fencing, etc.) and provide good economic incentive to farmers to plant A. torulosa. Acacia torulosa has large pods that are easily harvested. Furthermore, this species has large seeds which give it several advantages over those of A. colei for processing, namely, ease of harvest, ease of removing seeds from the pods and ease of separating the flour (germ) from the seed coat.

It should be noted that Acacia domestication and promotion in Niger is being undertaken simultaneously with a very successful program of promotion of natural regeneration of the indigenous flora.

 


Acacia torulosa. Direct sown seed, Maza Tsaye, Niger Republic.
Photo by Tony Rinaudo, Feb. 2005 .


Acacia torulosa . Basal branching, Maza Tsaye , Niger Republic.
Photo by Tony Rinaudo, Feb. 2005.


Acacia torulosa . Resprouting well following severe ground level pruning.
Photographed at Maza Tsaye, Niger Republic, by Tony Rinaudo, Feb. 2005.


Peter Cunningham inspecting A. torulosa pruned at 1 m above ground level.
Photographed at Maza Tsaye, Niger Republic, by Tony Rinaudo, Feb. 2005.


Peter Cunningham and Ibrahim Yahaya demonstrating the arborescent form of A. torulosa at Dandja, Niger Republic.
Photo by Tony Rinaudo.


Acacia torulosa . Resprouting well following severe ground level pruning.
Photographed at Maza Tsaye, Niger Republic, by Tony Rinaudo, Feb. 2005.


Acacia torulosa pods are large and easily harvested.
Photographed at Maradi, Niger Republic, by Tony Rinaudo.


Acacia torulosa seed in bowl.
Photographed in Niger Republic, by Peter Cunningham.

Some useful links

Harwood et al.

Developing Australian Acacias as a human food for the Sahel. Paper by C.H. Harwood, T. Rinaudo and S. Adewusi originally published in: Unasylva 50(196): 57-64 (1999).

Thomson et al.

Australian acacias -untapped genetic resources for human food production in dry tropical Sub-saharan Africa. Paper by L.A.J. Thomson, C.H. Harwood and T. Rinaudo, originally published in: FAO Forest Genetic Resources Information 24: 69-75 (1996).

Wickens

Role of Acacia species in the rural economy of dry Africa and the Near East (FAO 1995). Information on uses and role of indigenous and introduced Acacia species.

Text by:

Tony Rinaudo (Senior Country Program Coordinator, Africa, Middle East and Eastern Europe team, World Vision Australia, 1 Vision Drive, East Burwood, Victoria 3151, Australia; email: rinaudot@wva.org.au) and

Lex Thomson (SPRIG Project Team Leader, Ensis, The joint forces of CSIRO and SCION (formerly Forest Research), PO Box E4008, Kingston, Canberra, ACT, 2604, Australia; email: Lex.Thomson@ensisjv.com)

Page last updated: Thursday 15 December 2016