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Indigenous soil and water conservation methods in Africa. Presented by: Becky Humphrey (MSc Water Resources). Introduction. What is indigenous knowledge? ‘The knowledge used by local people to make a living in a particular environment.’
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Indigenous soil and water conservation methods in Africa. Presented by: Becky Humphrey (MSc Water Resources)
Introduction What is indigenous knowledge? • ‘The knowledge used by local people to make a living in a particular environment.’ • ‘A body of knowledge built up by a group of people through generations of living in close contact with nature.’
Indigenous knowledge is based on: • Adapting to the specific requirements of local people. • Creating and experimenting with methods to suit local environmental conditions. • The incorporation of outside influences, together with inside innovations. • Cultural knowledge • Consideration of social, political, economic and spiritual aspects of the local lifestyle.
Soil and Water Conservation • Need to take holistic approach in dealing with any aspect of environmental conservation. • Soil processes and runoff processes affect each other, therefore it makes sense to use methods which incorporate both factors.
Types of SWC methods • Earth / stone bunds • Bench / step terraces • Improved planting pits • Micro basins • Pitting • Modification of contour ridges • Mulching • Contour stone bunds • mounds
Types of SWC methods (continued) • Strips • Vegetation barriers • Grass strips • Drainage ditches • Basin irrigation • Ridge cultivation • Raised bed cultivation • Hedge barriers
Focus on Africa • Long history of traditional farming methods. • Diverse landscape between & within individual countries. • Inhospitable terrain. • Harsh climatic extremes. • Usually very hot and dry, but problem of flash floods during rainy season also exists.
Case Studies • The Dogon Plateau, Mali • Southern Zimbabwe • Upper East Region, Ghana • Harerge Highlands, Ethiopia
Traditional SWC techniques on the Dogon Plateau, Mali. Area Characteristics • Agricultural economy (cereal cultivation & market gardening) • Subsistence farming with limited cash crops • Main crops are Sorghum & Millet • Main garden crops are onions & tomatoes • Rainfall low & variable
Problems • Droughts lead to poor crop production • Heavy rainfall leads to severe soil erosion and pan formation • Soil has poor structure • Steep hillsides • Area densely populated • Only 10-15% of plateau is arable land
Development of indigenous methods • Hillsides originally populated because Dogon people hid from invaders in caves • Despite the fact that this is no longer an issue and good arable land exists elsewhere, population is concentrated here because of traditional values and cultural reasons • SWC necessary for survival
Traditional SWC techniques • Cones / mound making • Terracing of fields and hillsides • Stone lines • Bunds / low stone walls • Square basins • Planting holes
More unique methods • Stalks left after harvest are cleared away and then laid on the soil surface in bands to reduce soil erosion. • When the organic matter eventually decomposes it provides another benefit through increased soil fertility due to added nutrients
The Future • Labour shortages due to migration are threatening SWC techniques • Land tenure problems • However, increasing role of women & assistance through participatory development is promising.
Indigenous SWC in Southern Zimbabwe • SWC has played important role in development of smallholder agriculture. • Long tradition of indigenous farming methods threatened by mechanisation and political intervention
Historical SWC • Farming based on livestock & shifting cultivation • Livestock = food, clothing, transport & manure (also social status) but not enough draught power. • Main crop was Finger Millet. • Bush clearance led to cultivation of 3-10 yrs, then fallow. • Wetlands also cultivated (ideal during drought) • Hunting & gathering • Traditional values ensured conservation (esp. water & trees) • Low population & limited tools • Use of intercropping, mulching, bunds & ridges.
The Plough • Plough introduced by white settlers in late 19th century • Adopted by local farmers on large scale 1920-1940 • Indigenous farming saw many benefits in increased production • Erosion occurred on large scale (rills & gullies) & land took longer to recover from fallow.
Government Intervention • 1930 onwards: erosion became serious problem • Colonial government forced building of contour ridges and lowering of stocking rates • Also prohibited wetland use • Unpopular, esp. as ridges unsuitable for dry climate • Shifting cultivation & bush fallow ended • Use of plough encouraged • Poorly constructed ridges increased gully erosion
The Liberation Struggle • 1976-1980 = liberation struggle • Farmers encouraged to abandon ridges • New government could not enforce SWC • Farmers associated SWC with ridge building & therefore opposed to SWC • Village development committees established • Gradually, need for SWC realised
Problems • Attitude based on historical contempt for local knowledge in favour of Western mechanisation • Previous indigenous SWC methods inappropriate due to increased population density • Confusion over land rights
Solutions for the future • 2 projects: Food Security & Conservation Tillage • Incorporation of traditional SWC methods • Participatory approach has led to encouraging response • Membership of farmer clubs increased • Particular interest in garden crops & SWC
The Yaba-itgo system in Upper East region, Ghana Area characteristics • Savannah grassland belt • Erratic rainfall May-September, but often lull in growing season • Dry & dusty winds during dry season • Sandy soil with little OM • Rain fed crops (millet), subsistence farming • Garden crops during dry season • Small livestock
Problems • Farmers cannot afford livestock & equipment for ploughing • Renting land discourages SWC • Women deterred from SWC, despite being good at it • Isolation during rainy season • Exploitation by middle men • External intervention usually abandoned by farmers
Yaba Itgo: ‘Grandfather’s way of doing’ • Wide range of SWC methods • Usually aim to conserve moisture on steep slopes • Also encourage runoff if area prone to flooding • Methods never used in isolated way • Clear division of labour between gender and age
Erosion Control • Dependant on household labour availability • Stone bunding • Contour tillage • Border grasses • Strip cropping • terracing
Drainage control • Dependant on communal labour availability • Focus on flood risk due to cash crops • Land smoothing / levelling • Graded furrows
Recent Changes • Driving force changed from cultural reasons to production incentives • SWC blended with agronomic practices e.g. mixed cropping, cultivation of groundnuts, mulching • Bush burning greatly reduced, so soil fertility improved • Some incorporation of live fencing & use of livestock for ploughing (opposed still by women)
Indigenous SWC techniques of the Harerge Highlands, Ethiopia Area characteristics • Hilly terrain (low-moderate relief) interspersed with sloping valleys • High population density • Stony soil, rocky outcrops • Erratic rainfall regime (2 seasons) • Erosive tropical storms
Problems • Lower & more unreliable rainfall • Decline in soil fertility • Shortage of fertilizer (organic & inorganic) • Shortage of livestock for ploughing • Prevalence of pests & disease • Migration of farmers to urban areas
Traditional SWC methods • SWC methods have increased due to decline in agricultural productivity • Use wide range of agronomic, biological & mechanical measures • Knowledge has evolved over time in response to local needs • Crop rotation, intercropping, cactus / grass strips • Focus on increased soil fertility, reduced erosion & diversification
Stone bunds 3 benefits: • Remove stones from field, easier to plough • Slows runoff & traps moisture • Stops erosion & traps nutrients Soil bunds also used: • Not as stable but easily moved / rebuilt • Can evolve into terraces if left to mature
Outside intervention Development programs have gone wrong: • Farmers not consulted • Large scale engineering as opposed to gradual build up when needed • Livestock / human passage ignored
Disadvantages of traditional SWC • Most methods require a high level of manpower, but many younger members of families are leaving rural locations in search of more prosperous employment • Often cannot be carried out on a large scale • Need for some inclusion of modern methods
Advantages of indigenous SWC • Local people have managed the land for generations and know what is needed • Low cost • Simple methods that can be learned quickly
Conclusions • Indigenous methods of SWC are long established and work well • However, their success is largely affected by political factors and intervention by developed countries, NGO’s etc. • There is an ever increasing need for cooperation and understanding between researchers, engineers, local farmers etc. • Some cultural traditions & gender issues need to evolve in order for indigenous SWC to survive in Africa.
The importance of indigenous knowledge ‘Incorporating indigenous knowledge into research projects can contribute to local empowerment and development, increasing self-sufficiency and strengthening self-determination.’