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https://e-catalogs.taat-africa.org/com/technologies/contour-bunding-technique-cbt-contour-bunds-for-water-harvesting
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Contour Bunding Technique (CBT) Contour Bunds for Water Harvesting

CBT: Nurturing Crops, Conserving Soil, and Cultivating Resilience

The “Contour Bunding Technique (CBT)” is a farming method that helps deal with the problems of not having enough water and soil being washed away in dry farming, especially in Africa’s dry areas. This method uses a series of small walls, built in certain patterns along the curves of the fields. These walls make small areas that collect water. They stop water from running off, help catch more rain, store more water, and let water sink deep into the ground. By reducing water running off the surface and stopping soil from being washed away and ditches from forming, CBT greatly improves the soil’s ability to hold water. This is a simple but professional way to explain the concept.

2

This technology is TAAT1 validated.

8•7

Scaling readiness: idea maturity 8/9; level of use 7/9

Cost: $$$ 9 USD

Drawing contour line per ha

40 %

Runoff reduction

20 %

Sediment loss dicrease

IP

Open source / open access

Problem

  • Water Scarcity: In dryland farming, there is often a shortage of water due to irregular and insufficient rainfall. This makes it difficult to grow crops and sustain agriculture.
  • Soil Erosion: In dry areas, the soil is easily washed away by wind and water. This leads to the formation of gullies and the loss of fertile topsoil, which negatively impacts the health and productivity of the soil.

Solution

  • Strategic Wall Placement: The small walls, or bunds, are built along the natural curves of the fields. This design helps to trap runoff water that would otherwise be lost.

  • Creation of Micro-Catchments: These bunds create small water collection areas, or micro-catchments, that help to capture and store more rainwater.

  • Deep Water Infiltration: By trapping the water, the technique allows for deep water infiltration into the soil, enhancing the soil’s water retention capacity.

  • Soil Erosion Prevention: The bunds also help to prevent soil erosion and gully formation by reducing the speed and volume of surface runoff.

Key points to design your business plan

For Farmers 

 

For a farmer who wants to use the Contour Bunding Technique (CBT) in their farm, here are the steps:

  1. Understand the Benefits: Learn about the advantages of CBT, such as improved crop production, soil fertility, and watershed management.

  2. Get Trained: Attend training sessions on how to use land surveying equipment and methods for constructing cost-effective bunds.

  3. Analyze Your Farm: Understand the water movement across your farm landscape to determine the best placement of bund structures.

  4. Gather Resources: Ensure you have access to necessary resources such as animal-drawn or motorized ploughs, low-cost stone resources, and seedlings of fast-growing trees for building and reinforcing bunds.

  5. Implement CBT: Start constructing the bunds along the contour lines of your farm. Remember, the bunds should be arranged in specific patterns to create micro-catchments that can intercept runoff, increase rainfall capture, and promote water storage and deep infiltration.

  6. Monitor and Adjust: After implementation, monitor the effects of CBT on your farm, such as changes in crop yields, soil health, and water management. Use this information for continuous improvement.

More

Positive or neutral impact

Adults 18 and over
Positive high
The poor
Positive high
Under 18
Positive low
Women
Positive high

Positive or neutral impact

Climate adaptability
It adapts really well
Adaptability for farmers
It helps a lot
Biodiversity
It helps them grow and thrive
Carbon footprint
It reduces emissions a lot
Environment
It makes a big difference
Soil quality
It makes the soil healthier and more fertile
Water usage
It uses a lot less water

Countries with a green colour
Tested & adopted
Countries with a bright green colour
Adopted
Countries with a yellow colour
Tested
Egypt Equatorial Guinea Ethiopia Algeria Angola Benin Botswana Burundi Burkina Faso Democratic Republic of the Congo Djibouti Côte d’Ivoire Eritrea Gabon Gambia Ghana Guinea Guinea-Bissau Cameroon Kenya Libya Liberia Madagascar Mali Malawi Morocco Mauritania Mozambique Namibia Niger Nigeria Republic of the Congo Rwanda Zambia Senegal Sierra Leone Zimbabwe Somalia South Sudan Sudan South Africa Eswatini Tanzania Togo Tunisia Chad Uganda Western Sahara Central African Republic Lesotho
Countries where the technology has been tested and adopted
Country Tested Adopted
Burkina Faso Tested Adopted
Chad Tested Adopted
Ethiopia Tested Adopted
Kenya Tested Adopted
Mali Tested Adopted
Niger Tested Adopted
Nigeria Tested Adopted
Senegal Tested Adopted
Sudan Tested Adopted
Tanzania Tested Adopted
Zimbabwe Tested Adopted

This technology can be used in the colored agro-ecological zones. Any zones shown in white are not suitable for this technology.

Agro-ecological zones where this technology can be used
AEZ Subtropic - warm Subtropic - cool Tropic - warm Tropic - cool
Arid
Semiarid
Subhumid
Humid

Source: HarvestChoice/IFPRI 2009

The United Nations Sustainable Development Goals that are applicable to this technology.

Sustainable Development Goal 2: zero hunger
Goal 2: zero hunger
Sustainable Development Goal 13: climate action
Goal 13: climate action

  • The first step involves a collaborative field visit by farmers and a technician to assess slope direction, water movement, local practices, community regulations, and neighbor relationships, preventing unwanted water drainage and fostering cooperation.

  • The second step is to identify contour lines using land surveying tools and mark them temporarily.

  • Bunds are constructed either manually or with an ox-drawn plough, typically requiring three to four plow passes to create a sufficiently tall bund (e.g., 50-80 cm).

  • The standard distance between bunds is 50 meters on slopes less than 1.6%, and it ranges from 20 to 30 meters when the slope is between 1.6% and 5%.

  • Fast-growing tree seedlings are planted at 3-meter intervals on the crest of the bunds to reinforce them and enhance their stability.

  • Soil bunds require regular maintenance and strengthening using a plough or hand hoe to ensure their effectiveness.

Last updated on 22 May 2024