1.2 Detalles de contacto de las personas de referencia e instituciones involucradas en la evaluación y la documentación de la Tecnología

Nombre del proyecto que financió la documentación/ evaluación de la Tecnología (si fuera relevante)

Programme d’Appui à l’agriculture Productive (GIZ / PROMAP)

Nombre de la(s) institución(es) que facilitaron la documentación/ evaluación de la Tecnología (si fuera relevante)

Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH (GIZ) - Alemania

Nombre de la(s) institución(es) que facilitaron la documentación/ evaluación de la Tecnología (si fuera relevante)

Misereor - Alemania

1.3 Condiciones referidas al uso de datos documentados mediante WOCAT

¿Cuándo se compilaron los datos (en el campo)?

01/07/2012

El compilador y la/s persona(s) de referencia claves aceptan las condiciones acerca del uso de los datos documentados mediante WOCAT:

Sí

2.1 Breve descripción de la Tecnología

Definición de la Tecnología:

Contour stone bunds are erosion control structures and improve water retention and infiltration into the soil, resulting in an increased harvest.

2.2 Descripción detallada de la Tecnología

Descripción:

Contour stone bunds are erosion control structures built with quarry rock or stones in series of two or three. They are constructed in lines along the natural contour of the land after 10-15 cm of the soil has been removed from the line where they are to be built. They should be built to a height of 20-30 cm from the ground and spaced 20 to 50 m apart depending on the inclination of the terrain.
The best results are achieved when contour stone bunds are used in combination with biological measures (planting of grass, trees and hedges) and the use of organic fertiliser and mulching.

Purpose of the Technology: Contour stone bunds protect the land against sheet erosion caused by runoff. They form a barrier that slows down runoff and spreads it more evenly over the land. By slowing the flow of water over the land, it can seep into the soil and prevents the loss of rainwater. The bunds also act as a filter, trapping fine waterborne particles of soil and manure, resulting in a build-up of sediment and the formation of terraces. The seeds of grasses and shrubs are also trapped by the bunds, favouring the establishment of natural vegetation along the structure. This further stabilises the soil and the bunds and contributes to conserving the biodiversity of plants and small wild animals (monitor lizards, birds, snakes and other reptiles). If good vegetation cover is developed on the stone bunds, they also lower soil temperature and provide protection against wind erosion. Excess water filters through the bunds and infiltrates into the soil. When rainfall is erratic, the stone bunds contribute to conserving more moisture in the soil for longer, which helps to alleviate water stress during dry spells. There is evidence that bunds that have been in place for over 15 years have positive effects on yields.

Establishment / maintenance activities and inputs: A minimum amount of upkeep is required, which essentially involves replacing stones dislodged by animals or water flow. The lifespan of a stone bund is over 20 years.
In order to optimise the positive effects of stone bunds, it is important to ensure that they are constructed closely following the natural contour of the land and in accordance with the established technical standards.
The means of transport required depends on the proximity of a quarry or a supply of stones (cart or lorry).

Natural / human environment: This technique is designed for cropland, but can also be used on forest/rangeland. It is suitable for areas in the Sahel and the Sudan with rainfall ranging between 300 and 900 mm/year and low-to-medium gradient terrain.
When rainfall is high, they protect the land in the event of heavy rain, a phenomenon that tends to increase with climate change.

2.3 Fotografías de la Tecnología

2.5 País/ región/ lugares donde la Tecnología fue aplicada y que se hallan comprendidos por esta evaluación

2.6 Fecha de la implementación

Si no se conoce el año preciso, indique la fecha aproximada:

• 10-50 años atrás

2.7 Introducción de la Tecnología

Especifique cómo se introdujo la Tecnología:

• mediante proyectos/ intervenciones externas

Comentarios (tipo de proyecto, etc.):

Known as traditional method in some areas. Improved and up-scaled as part of numerous projects in many semi-arid countries. German Developmenmt Cooperation has used the technology from the 1980s onwards to combat desertification and improve natural resource management e.g. PDRT (Projet de développement rural de Tahoua - Tahoua Rural Development Project), PASP (Projet de protection intégrée des ressources agro-sylvo-pastorales Tillabéri-Nord - Project for the Integrated Protection of Agricultural, Forest and Rangeland Resources in Tillabéri-Nord) and several other projects of GIZ/KfW and other donors.

3.1 Propósito(s) principal(es) de la Tecnología MST

• reducir, prevenir, restaurar la degradación del suelo

3.2 Tipo(s) actuales de uso de la tierra donde se aplica la Tecnología

Comentarios:

Major land use problems (compiler’s opinion): surface runoff, erosion by water and wind, fertility decline,

Nomadism: Yes

Semi-nomadism / pastoralism: Yes

Cut-and-carry/ zero grazing: Yes

Improved pasture: Yes

Other grazingland: agropastoralism

Selective felling of (semi-) natural forests: Yes

Forest products and services: timber, fuelwood, fruits and nuts, grazing / browsing, other forest products / uses (honey, medical, etc.)

Type of cropping system and major crops comments: farmers are mainly agropastoralists with some communities specialised on pure pastoralism

Constraints of common grazing land

Constraints of forested government-owned land or commons

3.3 Información adicional sobre el uso de tierras

Provisión de agua para la tierra donde se aplica la Tecnología:

• de secano

Comentarios:

Water supply: Also mixed rainfed - irrigated and post-flooding

Número de temporadas de cultivo por año:

• 1

Especifique:

Longest growing period in days: 120; Longest growing period from month to month: August to October

Densidad del ganado (si fuese relevante):

1-10 LU /km2

3.4 Grupo MST al que pertenece la Tecnología

• medida de pendiente transversal

3.5 Difusión de la Tecnología

Especifique la difusión de la Tecnología:

• distribuida parejamente sobre un área

Si la tecnología se halla difundida homogéneamente en un área, indique el área aproximada que cubre:

• > 10,000 km2

Comentarios:

Large-scale areas have been protected in most Sahel countries. German Development Cooperation (BMZ/GIZ/KfW) for example has had several projects in Chad, Burkina Faso, Niger, Mali, Benin, which have applied stone bunds on around 800.000 to 1.000.000 ha since the 90ies.

3.6 Medidas MST que componen la Tecnología

3.7 Principales tipos de degradación del suelo encarados con la Tecnología

Comentarios:

Secondary types of degradation addressed: Et: loss of topsoil

Main causes of degradation: soil management (Unadapted landuse methods, reduced or abandoned fallow periods), crop management (annual, perennial, tree/shrub) (Neglect of fallow periods and crop rotation), droughts (due to heat waves and unreliable rainfall), population pressure (rapidly growing population increasing pressure on land), land tenure (insecure access to land and collectively managed communal land), poverty / wealth (very poor population)

Secondary causes of degradation: deforestation / removal of natural vegetation (incl. forest fires) (deforestation through overgrazing and fire wood collection), over-exploitation of vegetation for domestic use (firewood collection), overgrazing (cattle, sheep and goats), change in temperature (Climate change: heat waves), change of seasonal rainfall (more variable onset of rain), Heavy / extreme rainfall (intensity/amounts) (more variable and intensive rains), wind storms / dust storms (frequent storms), floods (due to intensive rain storms), labour availability (some migration of men to nearby cities), education, access to knowledge and support services (high level of illiteracy)

3.8 Prevención, reducción o restauración de la degradación del suelo

Especifique la meta de la Tecnología con relación a la degradación de la tierra:

• restaurar/ rehabilitar tierra severamente degradada

Comentarios:

Secondary goals: prevention of land degradation, mitigation / reduction of land degradation

4.1 Dibujo técnico de la Tecnología

4.2 Especificaciones técnicas/ explicaciones del dibujo técnico

Contour stone bunds are built with quarry rock or stones in series of two or three. They are constructed in lines along the natural contour of the land after 10-15 cm of the soil has been removed from the line where they are to be built. They should be built to a height of 20-30 cm from the ground and spaced 20 to 50 m apart. The best results are achieved when contour stone bunds are used in combination with biological measures (planting of grass, trees and hedges) and the use of organic fertiliser and mulching.

Technical knowledge required for field staff / advisors: moderate

Technical knowledge required for land users: low

Main technical functions: control of dispersed runoff: retain / trap, control of dispersed runoff: impede / retard, control of concentrated runoff: retain / trap, control of concentrated runoff: impede / retard, stabilisation of soil (eg by tree roots against land slides), increase of infiltration, increase / maintain water stored in soil, water harvesting / increase water supply

Secondary technical functions: reduction of slope angle, improvement of ground cover, increase in nutrient availability (supply, recycling,…), increase of groundwater level / recharge of groundwater, sediment retention / trapping, sediment harvesting, reduction in wind speed, increase of biomass (quantity)

Bund/ bank: graded
Spacing between structures (m): 20-50
Height of bunds/banks/others (m): 0.2-0.3
Length of bunds/banks/others (m): 0.2

Material: Stone

4.3 Información general sobre el cálculo de insumos y costos

Especifique la moneda usada para calcular costos:

• dólares americanos

4.4 Actividades de establecimiento

	Actividad	Tipo de medida	Momento
1.	Levelling and marking out the contour lines	Estructurales
2.	collecting stones and loading them onto carts	Estructurales
3.	transporting the stones by cart	Estructurales
4.	constructing the bunds	Estructurales
5.	applying manure	Estructurales

4.5 Costos e insumos necesarios para el establecimiento

	Especifique insumo	Unidad	Cantidad	Costos por unidad	Costos totales por insumo	% de los costos cubiertos por los usuarios de las tierras
Mano de obra	Levelling and construction of bunds	ha	1,0	19,32	19,32
Equipo	Tools	ha	1,0	1,95	1,95
Otros	Transport of stones	ha	1,0	15,07	15,07
Costos totales para establecer la Tecnología					36,34

4.6 Actividades de establecimiento/ recurrentes

	Actividad	Tipo de medida	Momento/ frequencia
1.	Replacing stones dislodged by animals or water flow	Estructurales

4.8 Factores más determinantes que afectan los costos:

Describa los factores más determinantes que afectan los costos:

The exact cost per hectare of constructing stone bunds depends on the distance of the site from the quarry, the size of the quarry, the inclination of the terrain, which determines the spacing between the stone bunds, and the actual amount of stones transported in each lorryload. The prices below are provided as a guide.
Supply of quarry rock/stones: 24 m3 per 400 m of bund
Labour: 30 man-days per ha
• levelling and marking out the contour lines: 1 man-day
• collecting stones and loading them onto carts:
10 man-days
• transporting the stones by cart: 10 man-days
• constructing the bunds: 9 man-days
• applying manure.
Transportation by cart:
• 20 cartloads of stones
• 20 cartloads of manure (if used).
Transportation by lorry:
• 6 lorryloads (skip loader – 4.5 m3 per load).
Other costs: equipment (pickaxes, shovels, wheelbarrows, water-tube level, etc.).

5.1 Clima

5.2 Topografía

Comentarios y especificaciones adicionales sobre topografía :

Landforms: Also footslopes and valley floors

Altitudinal zone: 200 m a.s.l.

5.3 Suelos

Si se halla disponible, adjunte una descripción completa de los suelos o especifique la información disponible, por ej., tipo de suelo, pH/ acidez de suelo, capacidad de intercambio catiónico, nitrógeno, salinidad, etc. :

Soil texture (topsoil): Fine to medium (sandy to clayey loams)

5.4 Disponibilidad y calidad de agua

Comentarios y especificaciones adicionales sobre calidad y cantidad de agua:

Ground water table: > 10 m

Availability of surface water: Surface runoff generated by limited but intense rainfalls

5.5 Biodiversidad

5.6 Las características de los usuarios de la tierra que aplican la Tecnología

Indique otras características relevantes de los usuarios de las tierras:

Population density: 10-50 persons/km2

Annual population growth: 3% - 4%

(mostly poor households below poverty line).

Off-farm income specification: men migrate temporarily or permanently to cities for off-farm income, women and men seasonally carry out paid farm work

Market orientation of production system: Most households crop for subsistence (mainly for small agropastoralists) and surplus is sold on market (medium agropastoralists). Commercial markets: some vegetable growing and pastoralists.

Level of mechanization: Ox and donkey used for animal traction

5.7 Área promedio de la tierra que pertenece a o es arrendada por usuarios de tierra que aplican la Tecnología

5.8 Tenencia de tierra, uso de tierra y derechos de uso de agua

Tenencia de tierra:

• estado
• comunitaria/ aldea

Derechos de uso de tierra:

• comunitarios (organizado)
• individual

Comentarios:

traditional land use rights prevail. On fields individual land use rights, communal rights on pasture and forest land (collection of wood and other products (fruits, medicinal plants))

Land ownership: Also individual not titled

5.9 Acceso a servicios e infraestructura

6.1 Impactos in situ demostrados por la Tecnología

Impactos socioeconómicos

Producción

Disponibilidad y calidad de agua

Ingreso y costos

Impactos socioculturales

Impactos ecológicos

Ciclo de agua/ escurrimiento de sedimento

Suelo

Biodiversidad: vegetación, animales

Reducción de riesgos de desastres y riesgos climáticos

Otros impactos ecológicos

6.2 Impactos fuera del sitio demostrados por la Tecnología

6.3 Exposición y sensibilidad de la Tecnología al cambio climático gradual y a extremos relacionados al clima/ desastres (desde la percepción de los usuarios de tierras)

Cambio climático gradual

Cambio climático gradual

	Estación	tipo de cambios climáticos/ climas extremos	¿Cómo es que la tecnología soporta esto?
temperatura anual		incrementó	bien

Extremos (desastres) relacionados al clima

Desastres climatológicos:

	¿Cómo es que la tecnología soporta esto?
tormenta de lluvia local	no muy bien
tormenta de viento	bien

Desastres climatológicos

	¿Cómo es que la tecnología soporta esto?
sequía	bien

Desastres hidrológicos

	¿Cómo es que la tecnología soporta esto?
inundación general (río)	no muy bien

Otras consecuencias relacionadas al clima

Otras consecuencias relacionadas al clima

	¿Cómo es que la tecnología soporta esto?
periodo reducido de crecimiento	no se sabe

6.4 Análisis costo-beneficio

¿Cómo se comparan los beneficios con los costos de establecimiento (desde la perspectiva de los usuarios de tierra)?

¿Cómo se comparan los beneficios con los costos de mantenimiento/ recurrentes (desde la perspectiva de los usuarios de tierra)?

6.5 Adopción de la Tecnología

De todos quienes adoptaron la Tecnología, ¿cuántos lo hicieron espontáneamente, es decir, sin recibir incentivos/ pagos materiales?

• 50-90%

Comentarios:

Comments on acceptance with external material support: While in emergency programs erosion control structures are mostly implemented through cash/food for work this is not the case in natural resource programs. As concerns German Development Cooperation, cash/food for work has been used during the 80ies and 90ies to implement stone bunds. Thereafter most programs switched to a voluntary approach where only Tools and transport were provided but all labour has been provided by the beneficiaries without payment.

80% of land user families have adopted the Technology without any external material support

There is a little trend towards spontaneous adoption of the Technology

Comments on adoption trend: The success of this measure and implementation on a wide scale depend to a large extent on whether grants are available to cover the cost of transporting the stones required to the site, good community organisation and the capacity of the community to mobilise the necessary labour, the contribution required from the farmers.
The farmers’ commitment to implementing the measure largely depends on whether they are allowed to choose the sites to be improved in their area. Forcing them to begin the improvement work upstream, as dictated by the traditional watershed development approach, has often proved counterproductive. Most communities prefer to improve individual plots first in order to achieve immediate effects on crop production and leave the treatment of forest/ rangeland areas as a second step.

6.7 Fuerzas/ ventajas/ oportunidades de la Tecnología

Fuerzas/ ventajas/ oportunidades desde la perspectiva del compilador o de otra persona de referencia clave
There is evidence that bunds that have been in place for over 15 years have positive effects on yields. Grain yields increase by more than 40% for millet up to 15 years after the bunds were established, and there is no evidence to suggest that yields decline with time. This can be explained by improved soil structure, which increases infiltration, even after the bunds are completely silted up.
The lifespan of a stone bund is over 20 years. There is a progressive build-up of sediment behind the bunds, resulting in the formation of terraces. Although the capacity of the bunds to retain water declines as the sediment builds up, soil infiltration capacity increases, thanks to improved soil structure, and the slope becomes gentler thanks to the terracing effect. How can they be sustained / enhanced? Farmers can maintain water retention capacity by raising the height of the existing bunds. In some places, farmers take the stones from the original bunds when a ridge of vegetation has been established and use them to form new bunds between the old ones.
The decrease in surface runoff in the treated area reduces the flow of floodwater and the amount of sediment carried by the water downstream, thereby protecting the fertile land in the valley bottoms from siltation and gully erosion. How can they be sustained / enhanced? In order to optimise the positive effects of stone bunds, it is important to ensure that they are constructed closely following the natural contour of the land and in accordance with the established technical standards.
In dry years, while unimproved land produces nothing, land protected by stone bunds can still produce a harvest. How can they be sustained / enhanced? When stone bunds are used in combination with zai planting pits, sorghum yields can increase by 114-124%. When used in conjunction with the application of the right amount of organic fertiliser, sorghum yields can be doubled.
Higher crop production improves household food security in proportion to the area of a farm improved with bunds. Under the PASP in Niger, an average of 16% of the area of a farm was improved with stone bunds, resulting in an increase of between 8% and 33% in annual output with no other additional measures.

6.8 Debilidades/ desventajas/ riesgos de la Tecnología y formas de sobreponerse a ellos

Debilidades/ desventajas/ riesgos desde la perspectiva del compilador o de otra persona de referencia clave	¿Cómo sobreponerse a ellas?
In wet years, the bunds may cause waterlogging in some parts of the field, which can adversely affect some crops.	If this happens, farmers must open up a gap in the bunds to drain off the water.

7.3 Vínculos a la información relevante disponible en línea

Título/ descripción:

Good Practices in Soil and Water Conservation. A contribution to adaptation and farmers resilience towards climate change in the Sahel. Published by GIZ in 2012.

URL:

http://agriwaterpedia.info/wiki/Main_Page