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Technologies
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Small level bench terraces [Thailand]

Khan ban dai din khanard lek (Thai)

technologies_1404 - Thailand

Completeness: 76%

1. General information

1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Key resource person(s)

SLM specialist:
SLM specialist:

Cheewinkuntong Wichai

Wang Put Tan, Ban Santikiri, Amphur Mae Fa Luang, Chiang Rai 57110

Thailand

Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)
Book project: where the land is greener - Case Studies and Analysis of Soil and Water Conservation Initiatives Worldwide (where the land is greener)
Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
World Association of Soil and Water Conservation (WASWC) - China

1.3 Conditions regarding the use of data documented through WOCAT

When were the data compiled (in the field)?

30/05/2000

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

Yes

2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

Terraces with narrow beds, used for growing tea, coffee, and horticultural crops on hillsides cleared from forests.

2.2 Detailed description of the Technology

Description:

The terraces described in this case study from northern Thailand are found on hilly slopes with deep soils. The climate is humid and tropical, with 1,700-2,000 mm of rainfall annually. The main aim of the terraces is to facilitate cultivation of tea or coffee on sloping land: erosion control is secondary. Coffee and tea, as well as flowers and vegetables, are good alternatives to opium poppies - which it is government policy to eradicate.

Purpose of the Technology: After clearing natural and secondary forests by slash and burn, terraces are aligned by eye - and constructed by hoe. The width of the bed is 1.0-1.5 m depending on slope, though there are no specific technical guidelines. The length of each terrace can be up to 25 m. Down the slope, after every 3-4 terraces, there are lateral drainage channels, approximately 20-30 cm wide and 10 cm deep. Situated at the foot of a riser, each channel has a gradient of 0.5% or less. Excess water - some of which cascades over the terrace risers, with some draining through the soil - is discharged through these channels, generally to natural waterways. The risers are steep, with a slope of above 100%, and without a defined lip.

Establishment / maintenance activities and inputs: Natural grass cover develops on the risers: this is cut back by hand hoe or machete, or completely removed. The grass is often burned. After harvest (of annual crops), the land is left until immediately before the next rainy season. The terraces at this stage are covered by weeds and grasses. Land is then tilled by hoe. The weeds and grasses are removed and heaped in piles outside the cropped area. They are not composted or used for mulching - and here an opportunity is missed. Where soil fertility is a problem, chemical fertilizers are used. Maintenance includes building up/repairing of risers and levelling of terrace beds as required.

Natural / human environment: The technology was pioneered, and continues to be practiced, by refugee immigrants from China looking for new areas to start farming. These immigrants first came in the 1950s, and cultivated simply through slash and burn techniques. During the 1970s they visited relatives in Taiwan and brought back the idea of small terraces. Originally they settled illegally, but eventually they were given official permission to stay. However, official title deeds to their land have not yet been allocated.

2.3 Photos of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

Country:

Thailand

Region/ State/ Province:

ChiangMai

Further specification of location:

Amphur Mae Fa Luang

2.6 Date of implementation

If precise year is not known, indicate approximate date:
  • less than 10 years ago (recently)

2.7 Introduction of the Technology

Specify how the Technology was introduced:
  • through land users' innovation
Comments (type of project, etc.):

Taiwan.

3. Classification of the SLM Technology

3.1 Main purpose(s) of the Technology

  • improve production
  • reduce, prevent, restore land degradation
  • create beneficial economic impact

3.2 Current land use type(s) where the Technology is applied

Cropland

Cropland

  • Annual cropping
  • Perennial (non-woody) cropping
Main crops (cash and food crops):

Major cash crop annual cropping: Tee, coffee
Major cash crop perennial (non-woody) cropping: Vegetables, flowers

Comments:

Major land use problems (compiler’s opinion): - soil erosion on cultivated hillsides
- practical difficulties in tending tea, coffee, vegetables and flowers on sloping land: farming is much easier on levelled land
- Lacking of land ownership (The whole area is reserved forest.)
- Low price of agricultural produce.

Major land use problems (land users’ perception): 1. Lacking of land ownership. 2. Landusers do not have Thai citizenship; less than 20% have ID cards (not citizenship).
Forest: before SWC measures

3.3 Further information about land use

Water supply for the land on which the Technology is applied:
  • rainfed
Number of growing seasons per year:
  • 2
Specify:

Longest growing period in days: 150 Longest growing period from month to month: Dec - Apr

3.4 SLM group to which the Technology belongs

  • cross-slope measure
  • water diversion and drainage

3.5 Spread of the Technology

Specify the spread of the Technology:
  • evenly spread over an area
If the Technology is evenly spread over an area, indicate approximate area covered:
  • 1-10 km2
Comments:

Total area covered by the SLM Technology is 5 km2.

This practice has been done by tribal people such as E-kaw, Lahu, Lisu, Mien, Khin, Thai Yai, Haw Chinese, H'mong

3.6 SLM measures comprising the Technology

vegetative measures

vegetative measures

  • V2: Grasses and perennial herbaceous plants
structural measures

structural measures

  • S1: Terraces
Comments:

Main measures: structural measures

Secondary measures: vegetative measures

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

soil erosion by water

  • Wt: loss of topsoil/ surface erosion
chemical soil deterioration

chemical soil deterioration

  • Cn: fertility decline and reduced organic matter content (not caused by erosion)
water degradation

water degradation

  • Ha: aridification
Comments:

Main type of degradation addressed: Wt: loss of topsoil / surface erosion, Cn: fertility decline and reduced organic matter content, Ha: aridification

Main causes of degradation: deforestation / removal of natural vegetation (incl. forest fires), Lack of enforcement of legislation or authority

Secondary causes of degradation: other human induced causes (specify) (Agricultural activities), other natural causes (avalanches, volcanic eruptions, mud flows, highly susceptible natural resources, extreme topography, etc.) specify

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:
  • prevent land degradation

4. Technical specifications, implementation activities, inputs, and costs

4.1 Technical drawing of the Technology

Author:

Mats Gurtner

4.2 Technical specifications/ explanations of technical drawing

Layout of small level bench terraces. After every third or fourth terrace a lateral drainage channel is built. Later, protective grass cover is established on the risers (right).

Technical knowledge required for field staff / advisors: moderate

Technical knowledge required for land users: moderate

Main technical functions: control of dispersed runoff: retain / trap, reduction of slope angle, reduction of slope length

Secondary technical functions: control of concentrated runoff: impede / retard, increase of infiltration, increase / maintain water stored in soil

Vegetative measure: grass on risers (optional)
Vegetative material: G : grass

Vegetative measure: Vegetative material: G : grass

Vegetative measure: Vegetative material: G : grass

Vegetative measure: Vegetative material: G : grass

Terrace: bench level
Vertical interval between structures (m): 0.4
Spacing between structures (m): 0.3
Height of bunds/banks/others (m): 0.4
Width of bunds/banks/others (m): 1.5
Length of bunds/banks/others (m): 25

Structural measure: drainage channels
Depth of ditches/pits/dams (m): 0.1
Width of ditches/pits/dams (m): .02 - .3

Construction material (earth): It is the earth dug in situ.

Lateral gradient along the structure: 0%

Vegetation is used for stabilisation of structures.

4.3 General information regarding the calculation of inputs and costs

other/ national currency (specify):

Baht

Indicate exchange rate from USD to local currency (if relevant): 1 USD =:

37.0

Indicate average wage cost of hired labour per day:

2.16

4.4 Establishment activities

Activity Type of measure Timing
1. Layout is simply by eye and best judgment. Structural
2. Work begins on the lower part of the slope, and then progresses uphill. Structural
3. Farmers cut into the hillside with hoes and drag the soil down to formthe risers and level the terrace beds. Structural
4. Risers are then stabilised/compacted by hoe. Structural

4.5 Costs and inputs needed for establishment

Specify input Unit Quantity Costs per Unit Total costs per input % of costs borne by land users
Labour Labour ha 1.0 270.0 270.0 100.0
Equipment Tools ha 1.0 5.0 5.0 100.0
Total costs for establishment of the Technology 275.0
Comments:

Duration of establishment phase: 12 month(s)

4.6 Maintenance/ recurrent activities

Activity Type of measure Timing/ frequency
1. Weeds and grasses are removed and piled outside the cropping area. Vegetative
2. Land is prepared through tillage by hoe. Structural
3. Risers are built up/repaired where necessary. Structural
4. Terrace beds may need levelling. Structural

4.7 Costs and inputs needed for maintenance/ recurrent activities (per year)

Specify input Unit Quantity Costs per Unit Total costs per input % of costs borne by land users
Labour Labour ha 1.0 45.0 45.0 100.0
Equipment Tools ha 1.0 45.0 45.0 100.0
Total costs for maintenance of the Technology 90.0
Comments:

Clearing of forest is not included in the cost calculations. This calculation is based on a typical slope of approximately 20%, with risers of 0.2 m in height and beds 1.0 m wide. Maintenance costs include basic land preparation (for annual crops) or weeding etc for perennial crops.

4.8 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

The slope factor affects most because it will require longer time to construct.

5. Natural and human environment

5.1 Climate

Annual rainfall
  • < 250 mm
  • 251-500 mm
  • 501-750 mm
  • 751-1,000 mm
  • 1,001-1,500 mm
  • 1,501-2,000 mm
  • 2,001-3,000 mm
  • 3,001-4,000 mm
  • > 4,000 mm
Specifications/ comments on rainfall:

Average 1600-1800 mm

Agro-climatic zone
  • humid

Thermal climate class: tropics

5.2 Topography

Slopes on average:
  • flat (0-2%)
  • gentle (3-5%)
  • moderate (6-10%)
  • rolling (11-15%)
  • hilly (16-30%)
  • steep (31-60%)
  • very steep (>60%)
Landforms:
  • plateau/plains
  • ridges
  • mountain slopes
  • hill slopes
  • footslopes
  • valley floors
Altitudinal zone:
  • 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.
Comments and further specifications on topography:

Slopes on average: Also steep (ranked 3)
Soil fertility: Low (ranked 1) and very low (ranked 2)
Soil drainage/infiltration: Medium (ranked 1, good drainage though being cleyey soil) and good (ranked 2)
Soil water storage capacity: Medium and low (both ranked 1)

5.3 Soils

Soil depth on average:
  • very shallow (0-20 cm)
  • shallow (21-50 cm)
  • moderately deep (51-80 cm)
  • deep (81-120 cm)
  • very deep (> 120 cm)
Soil texture (topsoil):
  • medium (loamy, silty)
Topsoil organic matter:
  • low (<1%)

5.6 Characteristics of land users applying the Technology

Market orientation of production system:
  • subsistence (self-supply)
  • commercial/ market
Off-farm income:
  • 10-50% of all income
Relative level of wealth:
  • poor
  • average
Level of mechanization:
  • manual work
  • animal traction
Indicate other relevant characteristics of the land users:

Population density: < 10 persons/km2
6% of the land users are rich and own 35% of the land.
24% of the land users are average wealthy and own 40% of the land.
60% of the land users are poor and own 20% of the land.
10% of the land users are poor and own 5% of the land.
Off-farm income specification: farmers spend much time as farm labourers on other farms or in food processing factories - and some have jobs at construction sites, for example road building
Level of mechanization: Manual work (ranked 1) and animal traction (ranked 2)
Market orientation: Commercial/market (ranked 1, tea, coffee, vegetable and flower production) and subsistence (ranked 2)

5.7 Average area of land owned or leased by land users applying the Technology

  • < 0.5 ha
  • 0.5-1 ha
  • 1-2 ha
  • 2-5 ha
  • 5-15 ha
  • 15-50 ha
  • 50-100 ha
  • 100-500 ha
  • 500-1,000 ha
  • 1,000-10,000 ha
  • > 10,000 ha
Comments:

Average area of land owned or leased by land users applying the Technology: Also 2-5 ha if farmers may farm at 2-4 plots far apart from each other.

5.8 Land ownership, land use rights, and water use rights

Land ownership:
  • state
Land use rights:
  • individual
  • illegal (initially) (see Annex T3)
  • illegal (initially) (see Annex T3)

6. Impacts and concluding statements

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

crop production

decreased
increased
Comments/ specify:

Production is not decreased.

production area

decreased
increased

land management

hindered
simplified
Income and costs

farm income

decreased
increased

economic disparities

increased
decreased

workload

increased
decreased
Comments/ specify:

Ease of cultivation. Can walk and work in the farm easier

Other socio-economic impacts

Input constraints

increased
decreased

Socio-cultural impacts

community institutions

weakened
strengthened

national institutions

weakened
strengthened

conflict mitigation

worsened
improved

Ecological impacts

Water cycle/ runoff

surface runoff

increased
decreased
Quantity before SLM:

20

Quantity after SLM:

15

Soil

soil moisture

decreased
increased
Comments/ specify:

During dry spells due to increased infiltration

soil cover

reduced
improved

soil loss

increased
decreased
Quantity before SLM:

50

Quantity after SLM:

10

Comments/ specify:

Soil erosion is reduced

nutrient cycling/ recharge

decreased
increased
Biodiversity: vegetation, animals

plant diversity

decreased
increased

animal diversity

decreased
increased

habitat diversity

decreased
increased

6.2 Off-site impacts the Technology has shown

reliable and stable stream flows in dry season

reduced
increased

downstream flooding

increased
reduced

downstream siltation

increased
decreased

groundwater/ river pollution

increased
reduced

wind transported sediments

increased
reduced

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?
Short-term returns:

slightly positive

Long-term returns:

positive

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?
Short-term returns:

slightly positive

Long-term returns:

positive

6.5 Adoption of the Technology

If available, quantify (no. of households and/ or area covered):

500

Of all those who have adopted the Technology, how many have did so spontaneously, i.e. without receiving any material incentives/ payments?
  • 50-90%
Comments:

10% of land user families have adopted the Technology with external material support

50 land user families have adopted the Technology with external material support

Comments on acceptance with external material support: estimates

90% of land user families have adopted the Technology without any external material support

450 land user families have adopted the Technology without any external material support

Comments on spontaneous adoption: estimates

There is a little trend towards spontaneous adoption of the Technology

Comments on adoption trend: There is a little growing spontaneous adoption: for example in the Mae Salong area farmers accept these terraces increasingly, but fruit growers tend to prefer intermittent ‘orchard terraces’ - terraces spaced apart, with 5 m or more of undisturbed land in-between. The benches in this case are backward sloping.

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
For facilitating picking of tea leaves
For using as farm path
For increasing soil fertility
Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
A relatively cheap method of terracing which makes cultivation easier and provides erosion control

How can they be sustained / enhanced? Should be further promoted by extension
agencies (in areas where cultivation is officially allowed). Allocation
of official title deeds to land will speed up the adoption automatically.
For improving/maintaining soil fertility
For increasing the yield of tea leaves

How can they be sustained / enhanced? Inspecting the field during/after rain to see how efficient they are in conserving soil and water and repair as needed
For using as farm path
Compared with normal bench terraces, construction does not bring infertile subsoil to the surface.

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

Weaknesses/ disadvantages/ risks in the land user’s view How can they be overcome?
Farmers have to pay for its construction. The government may be able to help in the future.
Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view How can they be overcome?
Does not lend itself to mechanisation: the terrace beds are narrow and only suited to hand hoeing. Teach farmers techniques of composting and/or mulching.
In this situation grasses and weeds are merely piled and burned rather
than being used to improve soil fertility

7. References and links

7.2 References to available publications

Title, author, year, ISBN:

No references

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