有助于对技术进行记录/评估的项目名称（如相关）Sustainable Land Management Project, Bhutan (SLMP)
有助于对技术进行记录/评估的机构名称（如相关）HELVETAS (Swiss Intercooperation)
有助于对技术进行记录/评估的机构名称（如相关）Aga Khan Foundation (AKF) - 瑞士
有助于对技术进行记录/评估的机构名称（如相关）Sustainable Land Management Institute Organistatio (Sustainable Land Management Institute Organistatio) - 阿富汗
Earthen trenches with soil bunds built along contours in staggered design
The SCTs technology is documented by Sustainable Land Management Project/HELVETAS Swiss Intercooperation which is funded by Swiss Agency for Development and Cooperation (SDC), with close support and cooperation of the Agha Khan Foundation (AKF). The staggered Contour Trenches (SCTs) were constructed at a degraded site in Bamyan center (Bamyan province) by Agha Khan Foundation (AKF) project with financial support of the Canadian International Development Agency (CIDA).
Totally 1470 contour trenches were constructed at the site, which has an area of 24 hectares.
The size of each trench measured 10 m in length, 0.6 m in width and 0.5 m in depth. The trenches had soil bunds on the lower side having a width of 1 m and height of 0.3 m. Contour lines were prepared using an A-frame and lime and the spacing between two contour lines was 8 m considering the slope. All the trenches were dug out manually. Local people were employed for construction works. Along with the SCTs, other measures were applied such as plantation of fodder grass, shrub and non-fruit trees, gully plugs, water harvesting tanks and brushwood plugs. The area is excluded from grazing and shrub cutting.
The land was extensive grazing land before the project implementation and got extremely degraded due to a lack of management by the land users. There was rampant exploitation of natural vegetation for meeting domestic energy needs and for grazing. Droughts, which frequently occur in the region, contributed to the slow degradation of the vegetation.
Purpose of the Technology: The main purpose of the technology is to reduce flash flood risks and improve land productivity (both upstream and downstream) so that more fodder, fuel wood and fruits could be produced and farmers affected by flash floods could grow more crops. The technology, which is part of a watershed technology system, helps in retaining runoff and sediment and improves soil moisture content. It also helps in water infiltration which eventually contributes to improved ground water recharge.
Establishment / maintenance activities and inputs: SCTs were established in a step-wise manner; as follows: (1) Site surveying, (2) Site mapping, (3) Planning, (4) Marking contour lines with the help of an A-frame, and (5) Trench excavation and bund construction.
The establishment cost for staggered contour trenches, was about 15,500 USD or 645 USD/ha. Most of the money was spent on labour. There have been no expenses in maintenance of SCTs since their establishment in 2008.
Natural / human environment: The technology is applied in semi-arid condition as the area receives annual rainfall of about 400 mm to address land degradation. The site formally belonged to the state but the local communities have use rights. AKF is still maintaining the site and using it for training and demonstration purpose. Several exposure visits for SLM specialist, land users, students and teachers have been also organized at the site.
Zai Mahmood village, Bamyan center, Afghanistan
- 0.1-1 平方千米
Total area covered by the SLM Technology is 0.24 km2.
Major land use problems (compiler’s opinion): Flash floods, gully/rill/sheet erosion, loss of natural vegetation and low productivity of the land due to degradation compounded by climatic factors.
Major land use problems (land users’ perception): Declining productivity of land resulting in shortages of fodder and fuel wood and loss of fertile land in the downstream areas due to flash floods.
Grazingland comments: The area is closed for livestock.
Future (final) land use (after implementation of SLM Technology): Forests / woodlands: Fp: Plantations, afforestations
Type of grazing system comments: The area is closed for livestock.
Number of growing seasons per year: 1
Longest growing period in days: 180; Longest growing period from month to month: April to September
Livestock density: 1-10 LU /km2
- Extensive grazing
Main causes of degradation: deforestation / removal of natural vegetation (incl. forest fires), over-exploitation of vegetation for domestic use, overgrazing
A detailed staggered contour trenches layout and its specifications (Fig. 1), and the cross section of soil bunds (Fig. 2)
Location: Bamyan. Bamyan center/Bamyan province
Technical knowledge required for land users: high
Technical knowledge required for SLM specialist: high
Main technical functions: control of dispersed runoff: retain / trap, increase of infiltration, sediment retention / trapping, sediment harvesting, increase of biomass (quantity), promotion of vegetation species and varieties (quality, eg palatable fodder)
Secondary technical functions: reduction of slope length, improvement of ground cover, increase in organic matter, increase / maintain water stored in soil, improvement of water quality, buffering / filtering water, spatial arrangement and diversification of land use
Retention/infiltration ditch/pit, sediment/sand trap
Spacing between structures (m): 8
Bund/ bank: level
Spacing between structures (m): 8
Height of bunds/banks/others (m): 0.5
Adapted from Bertran
|1.||Digging of the contour trenches and construction of the soil bunds|
|2.||Marking contour lines (A frame and lime)|
|劳动力||Digging of the contour trenches and construction of the soil bunds||persons/day/ha||100.0||6.43||643.0|
|设备||A frame and lime||ha||1.0||1.8||1.8|
Duration of establishment phase: 4 month(s)
|1.||No maintenance activities have been implemented for staggered contour trenches and soil bunds up to now.|
Despite the application of the structural measure of the SCTs AKF is still continuing its financial support for the plantation of the area. Thus irrigation which is a costly activity is still continued by AKF's support. The planted saplings of fruit and non-fruit trees are irrigated for six months/year, i.e. from April to September. Water is carried to the site by tankers. Each month, 75 tankers are used and the cost of one tanker is 12 USD or 600 Afghani. In addition, 16 persons are employed for one time irrigation.
- < 250毫米
- > 4,000毫米
Bamyan receives heavy snow falls and rain falls in winter season
Thermal climate class: temperate
- 0-100 m a.s.l.
- 101-500 m a.s.l.
- 501-1,000 m a.s.l.
- 1,001-1,500 m a.s.l.
- 1,501-2,000 m a.s.l.
- 2,001-2,500 m a.s.l.
- 2,501-3,000 m a.s.l.
- 3,001-4,000 m a.s.l.
- > 4,000 m a.s.l.
- 非常深（> 120厘米）
Soil fertility is very low - low
Soil drainage / infiltration is oor due to sealing
Soil water storage capacity is low
Difference in the involvement of women and men: Mainly men were involved in the activities due to cultural reasons.
Population density: 10-50 persons/km2
Annual population growth: 3% - 4%
100% of the land users are average wealthy.
Off-farm income specification: This is more applicable for poor small landholders or landless families.
- < 0.5 公顷
- 0.5-1 公顷
- 1-2 公顷
- > 10,000公顷
Formally, state owned. The site is now protected from open grazing and shrub cutting with support from the local communities.
Decreased production area
As the site is greener now
Especially of DAIL (Department of Agriculture, Irrigation and Livestock) and the persons who visit the site
livelihood and human well-being
Runoff, dew, snow, etc.
Due to better vegetation cover
SCT must be combined with vegetation and management measures
The benefits stated are the combined impacts of all measures-structural, vegetative and management. SCTs have helped in the establishment of vegetative measures by contributing to increased soil moisture, reduced runoff and soil loss.
Comments on acceptance with external material support: The whole project activities were implemented by external supports
There is no trend towards spontaneous adoption of the Technology
Comments on adoption trend: As the implementation of a watershed project requires high costs and investments which can not be affordable for the individual land users.
|The land users views were not considered.|
Helps in reducing flash flood risks due to less runoff
How can they be sustained / enhanced? Proper institutional mechanisms, involving the government, non-government and community institutions should be developed for sustaining project activities. Department of Agriculture, Irrigation and Livestock DAIL; (Bamyan) should take lead
Conserves soil and enhances soil cover and fertility leading to more on-site production
How can they be sustained / enhanced? Vegetative measures should be strengthened
|Complements re-greening efforts by reducing erosion and conserving moisture|
|The quality of contour trenches and soil bunds are very good and maintenance costs negligible|
|The site is used for demonstration, training and exposure visits|
|Establishment costs are very high||Voluntary community contributions, if they have an active stake in the project, would reduce the costs, otherwise, there has to be external support at least for the establishment phase|
|Loss of land for production||Planting suitable plants inside the trenches and along soil bunds|
|Requires high level of technical knowledge for establishment||Practical training for the target groups|